BIM for Advanced Daylighting - Autodesk Sustainability Workshop

BIM for Advanced Daylighting 

Brian Skripac, Assoc. AIA, LEED AP BD+C – DesignGroup 

MP4568 P Class Description 

A well day lit building can provide significant energy reductions and reduced operating costs for building 

owners of not only new construction projects but existing facilities. With electric lighting accounting for 35 

to 50 percent of the total electrical energy consumption in commercial buildings, design teams can 

leverage the optimal integration of daylighting strategies to offset this impact. This session will define the 

best practices and processes of implementing a BIM workflow with Revit Architecture and Ecotect 

Analysis. Additionally, we will outline the relevant project properties needed to accurately obtain the 

quality and reliable analytical information to effectively validate design decisions that can have the most 

beneficial impact on the building’s performance and lifecycle costs. 

Learning Objectives 

At the end of this class, you will be able to: 

• Define the energy impacts and performance benefits from natural daylighting. 

• Identify a workflow to optimize your existing Revit geometry in Ecotect. 

• Define the key material performance properties that will impact your analysis results. 

• Demonstrate the effective use of Ecotect and the Radiance plug3in to document the natural daylight 

levels in a space. 

About the Speaker 

As the Director of BIM at DesignGroup, Brian Skripac leads the integration of building information 

modeling (BIM) technologies for all projects. Currently, he is actively engaged in the research and 

application of sustainable technologies for use in project designs. In addition to managing BIM, Brian is 

frequently solicited by institutions, as well as professional organizations, to present his expertise. Brian 

has transformed the firm's approach to design and construction; and he seeks to educate clients, 

consultants, and colleagues on the benefits and value BIM brings to industry. Brian holds a bachelor of 

science in architecture from The Ohio State University, is a LEED® accredited professional, and an 

Autodesk® Revit® Architecture certified professional. He currently serves as an Advisory Group member 

for the AIA Technology in Architectural Practice Knowledge Community (TAP KC) at the national level, as 

well as being the chair of the AIA Columbus TAP KC. 

Email: bskripac@designgroup.us.com 

Twitter: @BrianSkripac


Energy impacts and performance benefits from natural daylighting. 

History of Daylighting 

Daylight is the oldest source of illumination and has been leveraged by the earliest civilizations from 

around the world. Whether it was the ancient Greek, Roman, Egyptian or Mayan civilizations the sun has 

played an important role in shaping the architecture of their time. As an essential element of life, these 

civilizations were planned around the direct light from sun, moon and stars and indirect natural light 

generated from these sources. 

Value of Daylighting 

Energy Consumption as defined by the U.S. Department of Energy (2005). 

In addition to lighting accounting for approximately 24% of the total electricity used in a building, there is 

also an impact on the space cooling percentages. Roughly 20% of the electricity required for air3 

conditioning results from heat generated by lamps. This combined impact illustrated that nearly 50% of 

the electricity used in commercial building is directly and indirectly related to its lighting systems. 

The USGBC’s LEED Reference Guide for Green Building Design and Construction (2009 Edition) states 

that “a well designed daylit building is estimated to reduce lighting energy use by 50% to 80%, but must 

2


evaluate and balance the impacts of heat gain/loss and glare control.” As mentioned before the 

relationship to reduced energy costs from the reduction in lighting and the ability to offset additional heat 

generation are key, but there are many other opportunities where daylighting can bring value to a design 

project. 

Along with having a constant standard of light, a well daylit building allows for the occupants to have an 

enhanced level of visual acuity, along with an overall increased psychological and biological well3being. 

Research, such as the Heschong Mahone Group Study, also shows that well daylit buildings reduce 

absenteeism, increase productivity, and can increase grades in schools. Other impacts from the addition 

of windows in a project include the opportunity to leverage natural ventilation and other passive solar 

energy strategies to positively impact the heating and cooling loads for a building. 

Heschong Mahone Group Study 

Heschong Mahone Group, Inc. (HMG) provides professional consulting services in the field of building 

energy efficiency. They specialize in applying their knowledge of building design, construction technology, 

policy development and program design to the problem of making buildings more energy efficient. 

In 2003, the Heschong Mahone Group completed a second round of major human performance studies 

on behalf of the California Energy Commission's Public Interest Energy Research (PIER) program. These 

Daylighting and Productivity studies consider the impact of daylight on human performance, along with 

other aspects of the indoor environment such as ventilation and view. Three of the studies include: 

• Windows and Classrooms: A Study of Student Performance and the Indoor Environment 

• Windows and Offices: A Study of Office Worker Performance and the Indoor Environment 

• Daylight and Retail Sales 

The results of these studies provided a wide range of conclusions validating the increase of productivity 

and human well being that can come from being in an environment that benefits from natural daylight. 

• Increased daylighting and the quality of light significantly improves students test performance and 

allowed their learning to progress 20% faster in math and 26% faster in reading, as compared to 

similar students in classrooms with less daylighting. 

• Of the 200 workers in a call center with good exterior views, it was found that they were able to 

process calls 6312% faster, and performed 10325% better on mental function tests. 

• Retail chain stores with significant daylight, reduced energy use by 50%, increased productivity 

by 10% and increased sales by 40%. 

Quality Daylighting 

Designing a well daylit building to achieve this type of performance and productivity outcomes is not as 

simple as creating a glass box. Daylighting can be defined as the controlled admission of natural light into 

a space, used to eliminate electric lighting which is not the same as just adding windows. 

When speaking of a quality lighting design we’re referring to a layered illumination plan that reduces 

energy cost, and conserves natural resources. It also allows users of space to function comfortably, feel 

safe, and appreciate the aesthetic components of the environment. This also requires one to think about 

daylight harvesting as a key component, which refers to capturing daylight for the purpose of illuminating 

interiors. Additionally, one must distinguish the difference between Sunlight and Daylight. 

3


Sunlight vs. Daylight 

• Sunlight is considered light that enters a space directly from the sun. This type of light is generally 

not good lighting for an interior. Direct sunlight can produce glare and excessive heat, which can 

fade materials. 

• Daylight or skylight is the term that describes the desirable natural light in a space. Daylight 

results in a perceived even distribution of light that avoids the glare and ill effects of the direct 

sun3light. 

Daylighting Design 

At DesignGroup, when designing with daylight and passive design strategies, we use the process 

“Energy as a Formgiver” and always think about the following question: 

What is the Impact of _______ on Building Performance & Energy Consumption? 

• Building Proportion 

• Window to Wall Ratio 

• Building Orientation 

• Shading Devices 

Utilizing these passive strategies with an 

iterative design process to gather analysis 

information from the outset of a design 

project can help shape the form and 

envelope conditions of a building. With this 

information available from the earliest 

stages of design you can have the most 

beneficial impact on a building’s 

performance and lifecycle costs. This also 

allows the design team to take advantage of 

their local climate conditions and having the 

building geometry react specifically to its 

site creating unique outcomes. 

In the United States it is important to balance southern and northern exposures against the east and 

west. 

• South facing glass allows for a high level of daylight but must control glare while maintaining 

natural light levels as well as balancing the wanted and unwanted solar gains of the 

summer/winter months. 

• North facing glass is ideal for letting even natural light in with little glare or solar gains. 

• East and West glass doesn’t work as well for daylighting. They capture a lot of light during the 

morning and afternoon, but also come with excessive glare and unwanted heat in the summer 

months. 

• Other useful design features can include the use of the following: roof monitors and clerestories, 

multistory spaces, roof overhangs and sunshades, and light shelves 

These ideas all allow for context specific outcomes where building form, shape, fenestration, roof 

overhangs, light shelves and awning can become site specific resulting in unique architecture. 

The following link from the Energy.gov website has a great overview of daylighting called Energy 101: 

Daylighting 3 http://energy.gov/building3design 

4


These strategies can also have positive outcomes in optimizing design decisions for existing buildings. 

Being able to simulate illuminance values in existing building spaces can provide the quantitative 

feedback owners need to make evidence based decisions on whether or not to make capital investments 

on investment re3lamping initiatives for their facilities. 

Case Study: 

DesignGroup’s Office 

The Case Study model that we chose to use 

for this presentation was DesignGroup’s 

existing five story 64,000 square foot office 

building in Columbus, Ohio. 

With a long north/south facade the building 

leverages many different passive design 

strategies allowing for a high level of 

consistent daylight deep into to the space. 

Even with these high levels of daylight, the 

building works to effectively minimize glare 

and balance; the unwanted solar gains of the 

summer months against the wanted solar 

gains of the wintertime in Ohio. 

In the past we had modeled the envelop of our building to use as an internal case study to define a 

working process for creating energy models and understanding how to best manage the development of 

gbXML models. Since this initial effort our firm had gone through an interior finish upgrade project which 

enabled much of our occupied spaces to be modeled. With this information in place we decided to use 

our building as an example model for capturing daylight analysis and proving our workflow for 

documentation of the LEED credit 3 IEQc8.1: Daylight and Views – Daylight. 

As we built out the rest of our building information model and began working on this project we also 

thought we would implement another study in addition to the development of this AU presentation. As we 

worked to document whether or not our building would meet the LEED IEQc8.1 requirements, we also 

wanted to see how the Ecotect Analysis and Radiance simulation results compared to actual light meter 

readings of our space. With this in mind we selected a series of design studios and conference rooms on 

both our 3rd and 4th floors (seen highlighted in green above) to analyze. 

5


To begin to understand these specific areas of our building we ran through a process of first isolating 

those areas of our Revit model then bringing them into Ecotect to define an analysis grid. Able to utilize 

that information back in Revit Architecture we the documented a series of work points that we could then 

reference as regularly occupied spaces for the LEED documentation process. We also built a light meter 

node family in the Revit model to hold both the existing and simulation illuminance value readings which 

was used to generate schedules and other comparative results. 

The analysis grid we used was based the LEED IEQc8.1 documentation requirements which we will 

discuss later in this document. This resulted in capturing 178 light meter reading points that were 

transferred onto the floor with blue painters tape. With this information in place our team took readings at 

each point in the office at 9:00 a.m. and 3:00 p.m., (following the LEED credit criteria). We also took 

readings at 12:00 p.m. to capture the sun at its highest point in the sky. This process started on the 

Summer Solstice and was repeated on the 21 st of each month through September to drive a consistency 

of measurements. 

This effort proved to be an extremely educational process that allowed us to document how our space 

was performing and how it compared to an Ecotect simulation. It also allowed us to establish a process 

for using a BIM workflow to document the LEED IEQc8.1 credit for both new and existing building 

projects. 

6

Optimize Your Existing Revit Geometry in Ecotect. 

BIM Workflow: Revit–> 3ds Max Design –> Ecotect Analysis –> Radiance 


The Process: 

• Take the BIM offline 

• Define your BIM Workflow to Export Model geometry as a gbXML, DXF, or FBX file 

• Develop and/or convert the BIM with the end goals in mind 

o How detailed does the model need to be, what’s your final outcome: 

Design intent or LEED certification? 

o Where are specific materials and how will they be controlled in Ecotect? 

Where are different glazing types and wall/floor finishes? 

o How do you define floor assemblies to create relevant analysis grid definitions? 

• Export / Import the gbXML model into Ecotect Analysis 

o Solar Access Analysis, Solar Rays and Daylight Studies 

• Define Model Set3up in Revit Architecture 

• Export FBX Files from Revit Architecture 

• Use 3ds Max Design to Convert FBX file to a 3DS files 

• Import 3DS Geometry into Ecotect 

• Set Model Origin 

• Address How Glazing Panels are Modeled 

• Load Weather File 

• Set True North Orientation 

• Verify Model Integrity 

• Material Assignments 

o Determine Analysis Methodology 

o Assign Materials in Ecotect 

o Assign Materials in Radiance (definitions and syntax) 

o Apply Materials 

• Define LEED IEQc8.1: Daylight and Views – Daylight Requirements 

• Define Analysis Grid 

• Create Camera Views 

• Export to Radiance for Analysis 

o Radiance Image Viewer 

7

o Radiance Import 

• Analysis Grid Management 

o Changing Analysis Grid from Lux to Footcandles 

o Import and/or Export Analysis Grid Data 

• Outcomes 

o Data Output Options 

o LEED IEQc8.1: Daylight and Views – Daylight Documentation 

o Model Run Comparisons 

BIM Workflow: Export Model Geometry – gbXML, DXF, or FBX? 

Export a gbXML model 


A gbXML can be an extremely useful file format at the early design stages of any project. If you are in the 

early stages of design for a new building you may be able to capture this information from Project Vasari 

or the Revit model you may be working in. Additionally, existing buildings may already have a Revit model 

in place or you may find that using reality capture and laser scanning is a great way to document the 

building geometry. Either way taking the building information model offline and properly converting it into 

a gbXML model is an important step. 

Revit Architecture gbXML Ecotect Analysis 

During AU 2010 there was a class that did a great job documenting the best practices of how to create a 

clean gbXML file. This session was titled “ME23133P: Leveraging BIM for Energy Analysis” and was led 

by Jessica Miller, LEED AP, EIT – HVAC Designer at TRO Jung|Brannen. The session materials and 

recording are available to download on the Autodesk University website. 

While the gbXML model captures the building geometry as surfaces it can be extremely helpful in looking 

at overall daylighting strategies in a building, especially during existing building renovation projects or 

tenant build3outs where you may be going into an open raw space. Being able to easily reuse the gbXML 

file built for energy analysis will be helpful in understanding the amount and extents of where daylight may 

be coming into building. 

The gbXML file is also an efficient way to capture a solar access analysis study to define amount of direct 

and diffused solar radiation falling on the building. This information can be critical to defining where 

building elements should be added to protect from unwanted solar gains or define where ideal locations 

for a photovoltaic array might be on the building or site. 

8

Import a gbXML Model 

File > Import > Model/Analysis Data, and change file 

type to Green Building Studio gbXML files (*.XML). 

OR 

File > Open, and change file type to Green Building 

Studio gbXML files (*.XML). 

Ecotect will assign a Model Element Category to the 

objects in the gbXML file, but if Ecotect cannot 

understand what type of model element something 

should be it will categorize it with . 


To set the correct model category or the specific material assignment to those elements you can choose 

an item under the “Materials/Elements in the File” heading then pick the “Material” pulldown. From here 

you can select the appropriate type from the Material Type list such as “Set as Wall” or “Set as Floor”. 

From this pulldown you will also have the ability to pick the “Select Existing Material” option enabling you 

to choose the specific material you wish to assign to those elements in the file. 

An advantage to importing a gbXML 

file is that Ecotect will also assign 

each room or space from your Revit 

model to its own zone, making it an 

easy and recognizable way to 

navigate the file. Ecotect will also 

group each zone by level. 

Once you have assigned all of the 

model element categories or 

assigned the appropriate materials 

you can choose “Open As New...” 

Solar Access Analysis 

The Solar Access Analysis dialog sets up the calculation of solar radiation on model surfaces or over the 

Analysis Grid if it is currently visible. Solar access refers to the availability of incident solar radiation 

(insolation), on surfaces and points within your model. Solar radiation calculations use hourly recorded 

direct and diffuse radiation data from the weather file. 

In the 3D Editor Page you can select the geometry you wish to quantify the amount of available solar 

radiation on. Then go to the Calculate pulldown and choose Solar Access AnalysisS 

Incident Solar Radiation: Calculates the amount of global, direct and diffuse solar radiation falling on 

objects or the analysis grid. 

9


Current Date and Time: Calculate instantaneous values at the current date and time. Once calculated, 

values for each object will automatically update whenever the model date and/or time is changed. 

Objects in Model: Stores objects attributes. You can control these using the “Object Attributes Values” 

item in the Display Menu. Using the following to limit the objects for which the calculation is performed. If 

you did not pre3select anything, Ecotect will run the analysis over the entire model. 

If you pre3selected an item you will want to make sure 

you check the “Only use Selected Object” to run the 

analysis over those particular items. Use Existing 

Shading Tables: Uses shading masks from an inter3 

zonal adjacency calculation and/or those added within 

the Sun3Path Dialog. These will be automatically 

generated for any objects with such a mask already. 

Ecotect will quickly be able to run this analysis and 

because we chose the Current Date and Time option 

you will be able to adjust these variables and see live 

updates across the geometry in your model. 

If you want view this analysis with shadows on, make 

sure you have display shadows selected before you run the analysis or you will have to re3run it to 

animate the time lapse aspects if you choose to turn them on. Also be sure to run the analysis from the 

Visualize page, not 3D Editor page to make those shadows visible. 

10

If you are interested in variations over the 

surface of each facade, you we will first need 

to divide each surface up into a series of 

smaller surfaces. For this you will use the 

Surface Subdivision dialog. 

Note: The image to the right took about 20 

minutes to run. 

Solar Rays: 


In addition to simply projecting shadows, you 

can use objects tagged as solar reflectors to 

generate solar rays onto your model. Rays are traced from the current sun position, starting at the tagged 

object and into the model. Each ray is only drawn if it hits an object in the scene. 

• In the 3D Editor Page you can select an object like a roof or a sunshade. 

• From the Shadow Settings Panel you can go to the Tag Object As Section > Reflector > Tag 

Selected Objects. 

• Next you can select Show Solar Rays. 

Within the Solar Rays section you will also have control over “Spacing” or the 

density of the rays being projected onto the object. You can also define the 

number of “Bounces” or the number of inter3reflections to trace. 

The Solar Rays will be visible in both 3D Editor and the Visualize Pages and will 

automatically update whenever you change the date and time. To remove the 

selected items as reflectors or change what item is acting and a reflector you 

can go to Tag Object As Section > Reflector > Clear Tagged. 

Another way to work with Solar Rays is to draw a line in a plan view, select that object and tag it as a 

Reflector. This will allow the solar rays to be focuses on that element and give you a better understanding 

of how a specific space will be impacted and how light will enter the space throughout the course of a day 

or at any time of the year. 

Summer Solstice Fall Equinox Winter Solstice 

11

Export a DXF of FBX file? 


Over the past few projects our team has explored what the best way to export/import geometry into a 

model is. In the past DXF models were useful, but there always seemed to be problems with the 

geometry once it was in Ecotect. 

A plus to exporting a model out as DXF or FBX will enable you to easily isolate a section of your Revit 

model (using a section box) so you are not burdened with the entire building if you only need to study a 

specific area. 

Downsides to DXF: 

• Little control over exported layer structure 

• Objects grouped by model category and you 

are unable to distinguish different materials 

within those categories. 

• Once geometry is imported Ecotect 

collapses those layers into a single zone 

named for the file that was imported. 

• Significant triangulation of geometry once 

imported (even thought the native DXF 

looks good). 

The examples above coupled with how geometry often times becomes distorted once imported into 

Ecotect were found to be the biggest hurdles in this process. One common example is how curtainwall 

mullions and panels translate when imported into Ecotect Analysis via a DXF file as seen below. 

Exported as DXF Exported as FBX 

With this being said we ran a series of different export/import scenarios to find the best methodology to 

optimize control of elements, manage file size, minimize triangulation, and eliminate the distortion of 

building components. This outcome of this study was to export segments (with material/construction types 

in mind) of the model out of Revit as FBX models that could be imported into 3ds Max Design. Once here 

we could capture that geometry in 3ds Max Design at a high quality we found that exporting these models 

out as 3DS files would allow them to import into Ecotect Analysis without a loss of quality or becoming 

distorted. 

12

Revit Model Set up & Exporting 

Model Set up: Revit Architecture 

In Revit Architecture you will need to think about how the model is going 

to be used and how the geometry will be created to support that 

outcome. As discussed earlier we want to focus on exporting the model 

so it can be used to quantify daylight illuminance levels to support the 

documentation of the LEED IEQc8.1: Daylight and Views – Daylight. 

The way that we’ve chosen to approach this was to create a series of 

3D views that leverage filters to isolate like materials for exporting to 

FBX files as mentioned in the previous sections. This enabled us to 

have more access to the different aspects of the model in Ecotect. 

When we later import the individual model they will be on their own 

zone allowing for more control to select and modify them if needed later. 

The image to the right shows the 32 separate 3D views that were 

created for this project. This made it very easy for us to distinguish 

between the different types of glazing systems as well as wall material 

that were in the existing building. 

For example there are separate files for Glazing_Exterior East & West 

and Glazing_Exterior North & South which have different Visible 

Transmittance value and need to be documented accordingly to ensure 

quality outcomes from the simulations that will be run in Ecotect. 

The image below shows how the Exterior Mullions, Sunshades and 

Spandrel Panels were isolated based on the being the same materials 

in a 3D view called “Mullions_Exterior Curtainwall, Spandrel, & 

Sunshades”. 


13


The 3D model export views above titled “Mullions_Exterior Curtainwall, Spandrel, & Sunshades” were 

able to be created using three filters for the model: 

• 00_Exterior_Solid Panels 

• 00_Exterior_Sunshades 

• 00_Exterior_Mullions_Clear Anodized 

We created all of the filters in the model based on 

understanding either the Family and Type Name 

parameter of the families in the project. Ideally we 

would have looked to use materials to filter objects by, 

but this is not a parameter that is available. Each 3D 

view could be comprised of multiple filters to capture 

all of the like elements that would need to be 

exported. 

For example there were two Generic Model families 

that made up the exterior sunshades on the building 

(one for the horizontal members and one for the 

vertical bracket). To be able to capture those items a 

filter was set3up to capture Generic Models who’s 

Type Name “begins with” 003Exterior3Sushade which allowed multiple families to be picked up. 

This was a process that we were able to replicate throughout the model for exterior as well as interior 

elements. 

14


Another part of your model structure to consider is how you construct/modify your floor conditions to be 

reused in defining analysis grids in Ecotect. In the images below you will notice that instead of having one 

large area of carpet the floors were broken up to allow for rooms to easily be isolated and selected for 

analysis as needed. This may not apply in every case, but it is important to understand the value of this 

workflow. 

In the 3D export views above, the image on the left used a series of filter that captured the concrete 

floors, columns, slab edges and roof (even though this view is a cutaway). Additional views and filters 

then captured the floors that were carpet and wood separately so they could be controlled in Ecotect. 

Even though there are multiple size concrete columns in this building it was simple to use the Filter Rules 

to Filter By: Family Name that Contains Concrete which captures all the differ conditions throughout the 

model. 

Exporting: Revit Architecture 

To Export the multiple 3D views you can: 

• Go to the Application Menu pulldown 

• Choose Export > FBX 

This allows you to export out each 3D view of like materials to an individual FBX file with like materials. 

15

Model Set up: 3ds Max Design 


At this stage 3ds Max Design will simply act as a conduit to translate the FBX file that was exported from 

Revit Architecture to a 3DS file that will be imported into Ecotect Analysis. 

The first thing you want to verify before you import and export the models is that your project units are 

set3up correctly. From the Customize pulldown select Units Setup: 

• Set Display Units Scale to US Standard: 

o Feet w/Fractional Inches 

o 1/32 

• Set System Units Setup 

o 1 Unit = 1.0 Feet 

To Import the FBX models you can go to the Application 

Menu pulldown choose and choose Import > Import then 

set your Files of Type: to Autodesk (*.FBX). 

Next you can simply hit OK when the FBX Import dialog 

box comes up. 

Now you are ready to Export the model by going back to the Application Menu pulldown choose and 

choose Export > Export then set your Save Type: to 3D Studio (*.3DS). 

Once you hit Save, you will 

receive a dialog box asking if 

you would like to “Preserve 

Max Texture Coordinates.” 

This will impact file size of the 

exported 3DS file but this 

information will not translate 

to the actual Ecotect file so 

you can feel free to uncheck 

the dialog box. 

16

Model Set up: Simplify Geometry as Needed in Revit Architecture 


Understanding the correct level of detail for your model is extremely important. As we compile this 

information to be translated into Ecotect we need to make sure that the models are not over detailed to 

the point of bogging things down. In addition to understanding what needs to be exported out for the 

daylight simulation you should also give consideration to model geometry and the amount 

curved/rounded objects they contain. Not only are file sizes of the individual models impacted but so is 

the overall consolidated model along with a significantly inflated time to import geometry. 

Round Faceted 

It is also important to see how these items can impact furniture and other major fixed equipment items 

that may be in the model. It is understandable that you will not need all of these items to run a daylighting 

but should be aware of these impacts. As we ran this model study we first imported all of the model 

geometry that was natively used in the design model and the model size grew to 507,114 KB. Taking 

these workflows into consideration reduced the final model size down to 35,000 KB. 

Ecotect Analysis Model Imports & Set up 

Import a .3DS file into Ecotect Analysis 

File > Import > 3D CAD GeometryS 

• Files of Type: 3D Studio (*3DS, *ASC, *PRJ) 

• Remove Duplicate Faces 

• Auto Merge Triangles 

• Scale Objects By: Feet 3> Millimeters (304.8) 

• Material – Set Material AsS 

• Import Into Existing 

Be sure to import geometry into the 3D Editor page 

not the Visualize page, which will help save time. 

File Type File Size 

Round 

FBX 13,400 KB 

3DS 6,286 KB 

ECO 86,875 KB 

Import Time +60:00 

Faceted 

FBX 5,977 KB 

3DS 1,144 KB 

ECO 8,474 KB 

Import Time 1:45 

Continue to import all of the individual 3DS files into the project and reassemble the model before moving 

on to the next step of resetting model origin. 

17

Set Origin 


Depending on where your origin is in your Revit model you may find that it needs to be redefined 

accordingly once you import your geometry into Ecotect. For instance if you building’s first floor (base 

level or origin) is set generically to 100’30” or specifically to an above sea level elevation like 742’39” in 

Revit you will have to address this to correctly define the ground plane in Ecotect Analysis. 

To define the ground plane in your project you can use the Set Origin button in the toolbars. 

Once you define a point in the model to serve as the origin, you are ready to “Rest World Origin”. 

• Go to the Modify pulldown 

• Select Transform Origin 

• Reset World Origin 

As seen in the images below, if you have redefined your origin then import additional geometry it will not 

fall into the correct location as before the origin was redefined. You will need to have a consistent point 

defined in the model to be able to move the geometry from one location to the other, but this can be done. 

Origin not re3defined Origin re3defined and geometry imported 

Model Setup: Glazing Panels 

Another important consideration in Ecotect is to understand how the glazing elements modeled in Revit 

Architecture will function and perform in Ecotect Analysis. The geometry that comes across from Revit will 

have a panel of glass represented as solid objects with six faces. This is acceptable for solid or opaque 

objects in Ecotect, but for glazing and transparent/translucent objects which will cause a high level of 

inaccuracy to your analysis outcomes. 

18


We will talk more about materials later Default Export Converted Glass on Right 

in this handout, but it is critical to 

understand the Visible Transmittance (Tvis) 

value that you will use. Manufacturers will 

have Tvis values readily available in their 

product literature. For example, a double 

glazed system with a Tvis of 70% is 

calculated for the entire assembly not 

each panel of glass. Meaning, the image 

on the left you will lose 30% of the light 

passing through the first panel of glass 

and another 30% in the second panel, 

creating an analysis that is showing a 

space that will receive much less natural 

daylight that it actually is. 

It is critical that your glazing systems be redefined to have only one plane of glass as seen in the images 

above to get an accurate simulation result. 

Load Weather File 

From the Zone/Cursor Toolbar in Ecotect select the “Set 

Current Time and/or Location” pulldown. 

If you already have a Weather Data File (*.WEA) you can 

load it here. If not you can select Find Weather DataS > 

U.S. Department of EnergySoption which will take you to 

the EnergyPlus Energy Simulation Software Weather 

Data page 3 

http://apps1.eere.energy.gov/buildings/energyplus/cfm/we 

ather_data.cfm. 

• Download the EPW (EnergyPlus Weather file). 

This file is based on the Typical Meteorological 

Year 3 (TMY3) derived from a 199132005 period of record. 

From the Zone/Cursor Toolbar in Ecotect select Convert Weather DataS(this will launch Ecotect: 

Weather Manager program). 

• File > Open and Select the .EPW file that you just downloaded. Select > Import File 

• Go to File > Save to save the file out as a Weather Data File (*.WEA) 

• Close Ecotect: Weather Manager 

From the “Set Current Time and/or Location” pulldown choose “Load Weather FileS”. Select the newly 

created weather file. Ecotect will ask you to “Update Global Position to Match Climate File?” – Say Yes 

Other climatological database include the Autodesk’s Climate Server which you can access through 

Green Building Studio and the Meteonorm software – www.meteonorm.com 

19

True North Orientation 

Even though you have globally located your project you will need to make sure that 

Ecotect understands the building Orientation on the site as it relates to True North. 

If you have set True North in Revit this information will carry over into Ecotect. If 

you haven’t, you can go to the Project Page to do so. 

North Offset / Orientation: Use this control to set the orientation of the North Point 

relative to the Y3axis of the model grid. This is always in degrees and is taken in a 

clockwise direction relative to the positive Y axis. 

Altitude: Use this to specify the height of the site above sea level. This is not 

currently used internally within any of Ecotect's calculations, but is exported to 

some external tools and may be used in the future. 

Local Terrain: This selector determines the surrounding terrain of the site and is 

used in thermal and natural ventilation calculations. This affects ventilation and 

infiltration rates in Ecotect's thermal calculations and is exported to some external 

tools. 

Verify Model Integrity 

Go to the Visualize Page to view your model as a solid. This will provide a great 

perspective of the integrity of the model you have imported. 

Shadow Settings Panel 

Turn on Display Shadows (Daily Sun Path and Annual Sun Path will also be 

available options from this section of the panel). 

• You can press and drag on the sun to change the time of day or year 

Or 

• In the “Set Current Time and/or Location” toolbar you can pick in the 

“Time of Day”, “Day of Month”, and “Month of Year” and scroll through 

with your middle mouse button to change the settings. 


20

Analysis Methods & Material Assignments 

Ecotect Lighting Analysis or Export Model Data to Radiance? 


Following the definition of your model geometry and the weather/location data you input in Ecotect 

Analysis the material assignments and analysis methods you choose will be the single biggest item you 

need to address in your process. There are two different workflows that you can define for how to capture 

a natural daylight levels in your model. One is to utilize the Lighting Analysis tools in Ecotect or you can 

decide to leverage Export Model Data to Radiance option to run the simulation. 

If you choose to run the Ecotect Lighting Analysis it is important to understand how the simulation is being 

run. The daylight illuminance levels in this analysis are not date or time dependant 3 they represent worst3 

case design conditions based on an 'average' cloudy or uniform sky distribution in mid3winter. 

Additionally, there can be a significant time difference in how much longer it takes a lighting analysis to 

run in Ecotect as compared to Radiance. 

If we’re looking to design around a specific date/time condition or quantity data for the LEED IEQc8.1 

documentation requirements this will not provide the needed feedback. For this you will want to leverage 

the “Export Model DataS” to Radiance function of Ecotect. This will allow you to take advantage of 

Radiance as a free radiosity3based physically accurate lighting simulation tool to address quantitative and 

qualitative daylighting issues. 

While there is a value to running your simulation using the CIE Overcast Sky Condition in Ecotect, you 

should be aware that you can also run your Radiance simulation with this Sky Condition along with a 

series of others. Additionally, the Radiance simulation will allow you to have more consistent results since 

each analysis will be utilizing the same material properties. 

Once the needed analysis methodology is established, materials should be considered next. 

Material Assignments 

Analysis Outcomes 

When the individual 3DS files were imported into Ecotect, general material categories were set by 

element type (Set as Wall, Set as FloorS). Next we need to focus on the specific properties of each 

material that will control how daylight is being dealt with during the analysis. 

Depending on what stage your design is in you may or may not know the exact properties of the 

construction materials in your project. If this is the case and you are trying to run some early general 

illuminance studies, the industry provides some basic rules of thumb to guide this early design process 

simulations. 

Rules of thumb for material reflectance: 

• 80% – Ceilings 

• 60% – Walls 

• 20% – Floors 

When looking to provide documentation in support of LEED credit (LEED IEQc8.1: Daylight and Views – 

Daylight) you can look at the LEED Reference Guide for insight. In the calculation section of the text for 

“Option 1. Simulation" in LEED IEQc8.1 the reference manual states that “the model should include 

glazing properties, as well as representative surface reflectance settings for interior finishes.” 

21

Material Assignments: Ecotect 


Whether you’re running this general or more detailed illuminance analysis it is critical to understand how 

materials are defined, function in the analysis engine, and and more importantly how Ecotect translates 

them to Radiance. The first step is to set3up the different materials that you will need in Ecotect. For each 

unique wall, floor, ceiling or glazing material a new element should be added to the Ecotect material 

library. Once added to the library you can define the appropriate material properties need for the analysis. 

This is where we need to understand a little more about the properties needed for daylighting analysis. 

When dealing with lighting analysis in Ecotect the materials dialog box will highlight that you should be 

concerned with four variables: Solar Heat Gain Coefficient, Visible Transmittance, Color (Reflect.), and 

Specularity. One of the main things to look into here, depending on the types of materials you are using, 

is to understand the relationship between these elements. One such item is how Color and Reflectance 

work together. 

The Ecotect Help files do a good job of explaining these materials: 

“Many Ecotect users have been confused over the lack of a reflectance setting for materials. Reflectance 

is solely a function of color (specularity simply determines the directionality of the reflected light, the color 

determines how much is reflected). Thus Ecotect internally derives reflectance from the assigned surface 

color. However, in order to allow users to specify a reflectance, a button has been provided that will 

modify the surface color based on the entered reflectance value.” 

Going back to our rules of thumbs and knowing that you have a ceiling with a Surface Reflectivity 80% 

you can plug that value in the following equation to understand where the RGB component values are 

coming from. 

RGB Value / 255 = Surface Reflectivity or 204 / 255 = 0.800 

This being said, one may ask the questions: What is the function of color in the model? The answer is 

that color doesn’t really matter much and shades of gray will provide the same accurate outcomes since 

the analysis software is concerned with the surface reflectivity driven from those RGB values. If that same 

RGB value is represented by a shade of gray you will receive the same outcome a seen in the following 

images. 

22


For instance, if there is a wall with a paint color RGB value of R386 | G372 | B3126 (which can be captured 

from most paint manufacturer websites) it will have a Surface Reflectivity of .322. If you already know the 

Surface Reflectivity value of a material you can type that in and will generate a gray color. For example if 

you know the Surface Reflectivity is .322 you will get an RGB value of R382 | G382 | B382 by using the 

equation below. 

RGB Value / 255 = Surface Reflectivity or 82 / 255 = 0.322 

Because the surface reflectivity is the same the outcomes will follow. The images below show the 

Radiance outcomes for two separate simulations with different color walls but the same Surface 

Reflectivity. 

Gray: R 82 | G 82 | B 82 Purple: R 86 | G 72 | B 126 

23

Material Assignments: Radiance Set up 

The previous images show the outputs from the 

Radiance simulation in both Ecotect and Radiance. 

When the Radiance simulation occurs it is necessary 

to understand how the Ecotect material properties are 

translated into RAD files for Radiance to use and 

where those files are created. 

By default a RAD file will be exported into the folder 

location as defined by the “Select Output File and 

Check InstallationS” dialog in your export to 

Radiance dialog. 

A best practice method is to define a location on your 

local machine as to avoid long file path names or 

names with spaces which may result in an error 

message from Radiance. This information can always 

(and probably will be moved) at a later date but this is 

an ideal starting location. 

You can also access this information by choosing the 

“Open Radiance Control Panel” in the Export to 

radiance dialog box. When you choose this option you 

will see that on the final screen of this series of dialog 

boxes that your Output Options will be set to “Run in 

RadianceCP.” When you hit OK the Radiance Control 

Panel dialog will launch allowing you to see and edit 

the Radiance analysis properties including the 

materials as seen in the image below. 


24

Material Assignments: Radiance Material Definitions 

While Ecotect will translate out materials to a RAD file 

it is not always a one to one translation which can 

cause inaccuracies in your results. A best practice for 

this process is to create individual RAD files for each 

material that was created in Ecotect (which can simply 

be done in Notepad by following the syntax outlined in 

the coming pages). Be certain the name of the RAD 

file name and the Ecotect Material name should be 

the same. 

The RAD files should not be located in the default 

location as mentioned earlier, but should be relocated 

to the same folder location as the Ecotect model that 

is being analyzed. This will allow the “Include Material 

Definitions” and the “Check for Material.rad files” to 

function correctly in the export to Radiance dialog box. 

Material Assignments: Radiance Material 

Syntax 

At a general level opaque objects like walls, floors roof 

and ceiling will translate out as what Radiance calls 

Plastics and Metals. Glazing elements will translate 

out to either Glass or Trans materials. The processes 

mentioned above will still hold true in Radiance, there 

is just some additional and more accurate information 

to be defined. 


Radiance materials have a standard syntax (that is described in the file ray.pdf in the Radiance 

documentation). The syntax is always: 

modifier type identifier 

n S1 S2 S3..Sn 

0 

m R1R2 R3 .. Rm 

For example a purple paint, would be: 

void plastic WALLS_PURPLE_PAINT 

0 

0 

5 .35 .35 .35 0.00 0.05 

void: is the definition of a new material 

plastic: is the material type 

colourwhite: is the name we have chosen to refer to this material 

5: is the number of following settings 

.35 .35 .35: is the red, blue and green reflectance 

0.00 and 0.05 is the specularity and roughness 

25


Plastic is a material with uncolored highlights. It is given by its RGB reflectance, its fraction of specularity, 

and its roughness value. Roughness is specified as the rms slope of surface facets. A value of 0 

corresponds to a perfectly smooth surface, and a value of 1 would be a very rough surface. Specularity 

fractions greater than 0.1 and roughness values greater than 0.2 are not very realistic. (A pattern 

modifying plastic will affect the material color). 

mod plastic id 

0 

0 

5 red green blue spec rough 

Metal is similar to plastic, but specular highlights are modified by the material color. Specularity of metals 

is usually .9 or greater. As for plastic, roughness values above .2 are uncommon. 

Glass is similar to dielectric, but it is optimized for thin glass surfaces (n = 1.52). One transmitted ray and 

one reflected ray is produced. By using a single surface is in place of two, internal reflections are avoided. 

The surface orientation is irrelevant, as it is for plastic, metal, and trans. The only specification required is 

the transmissivity at normal incidence. (Transmissivity is the amount of light not absorbed in one traversal 

of the material. Transmittance 33 the value usually measured 33 is the total light transmitted through the 

pane including multiple reflections). To compute transmissivity (tn) from transmittance (Tn) use: 

tn = (sqrt (.8402528435 + .0072522239 * Tn * Tn) 3 .9166530661) / .0036261119 / Tn 

Standard 88% transmittance glass has a transmissivity of 0.96. (A pattern modifying glass will affect the 

transmissivity.) If a fourth real argument is given, it is interpreted as the index of refraction to use instead 

of 1.52. 

mod glass id 

0 

0 

3 rtn gtn btn 

For example a glazing system with a 70% transmittance glass would incorrectly translate out of Ecotect 

(example on left) and should more accurate be dealt with as a RAD material file (example on right). 

void glass GLAZING_NORTH_SOUTH void glass GLAZING_NORTH_SOUTH 

0 0 

0 0 

3 0.697 0.763 0.763 3 0.763 0.763 0.763 

Trans is a translucent material, similar to plastic. The transmissivity is the fraction of penetrating light that 

travels all the way through the material. The transmitted specular component is the fraction of transmitted 

light that is not diffusely scattered. Transmitted and diffusely reflected light is modified by the material 

color. Translucent objects are infinitely thin. 

mod trans id 

0 

0 

7 red green blue spec rough trans tspec 

26

Material Assignments: Apply Materials 

To apply the specific material that has been created you should be in the 3D Editor Page. 

• Go to the Zone Management Panel 

• Right click on a zone one in the model (i.e. Floor_Carpet.3DS) 

• Right Click and choose “Select Objects On” 

• Next go to the Material Assignments Panel 

• Select the appropriate material from the (i.e. FLOORS_CARPET_DARK_GREY) 

• Select Apply Changes 

LEED IEQc8.1: Daylight and Vie Views – Daylight 

With all major model components defined it is important to look back at the LEED Reference Guide to 

define the remaining criteria for calculating daylight illuminance values. 

Option 1. Simulation 

• Create a daylight simulation model for the bui building, lding, or each applicable area. The model should 

include glazing properties, as well as representative surface ref reflectance lectance settings for interior 

finishes. 

• For each applicable area, include a horizontal calculation grid at 30 inches above the floor, or 

measured sured at the appropriate desk or work height level for the intended use of the space. This 

represents the typical work plane height. It is recommended that the calculation grid be set up 

with a regular size interval so that the grid has at least 9 measuri measuring g points in a room but with a 

maximum interval of 53feet feet to provide a detailed illumination diagram for each room. 

• Calculate the daylight illumination for each applicable space using the following daylight criterion: 

clear3sky sky conditions at both 9:00 a.m. and 3:00 0 p.m. on September 21 for the project’s 

geographic location. 

• Identify the area of the room that has daylight illumination between 10 footcandles and 500 

footcandles at both times (9:00 am and 3:00 pm). Spaces that do not meet the dayl daylight dayl 

illumination ion levels at both times do not qualify. 

• If the space uses automated view preserving shades, the maximum footcandle requirement does 

not apply. 

• Sum the square footage of all daylighted rooms or areas and divide by the total square footage of 

all applicable spaces. 

Define the Analysis Grid 

This process will allow us to leverage the way we set set3up the Revit model 

to be exported and brought into Ecotect Analysis. 

From the 3D Editor page you should select one of these predefined floor 

areas then select Auto3Fit Fit Grid to Objects.. 


27

Select Auto3Fit Grid to ObjectS 

• Type to Fit 

o Within 

• Fit Grid To 

o Selected Objects 

o In Which Axis – XY Axis 

o Axial Offset – 30” AFF (per LEED 8.1) 

• Boundary Inset 

o Leave unchecked 

• Specific Cell Size 

o 1’30” x 1’30” Grid (or needed grid size, while 

not exceeding the maximum interval defined 

by LEED) 

• Select OK to apply the analysis grid 

Create Camera View 

Go to a plan view. 

• Select the Camera tool or go to the Draw 

pulldown and Pick Camera 

• Choose “Interactively.” 

• Set your elevation prior to placing the camera. 

• Choose where you are standing with the 

camera, then select where you are looking. 

These camera views can be extremely useful in 

capturing other types of images when running the 

analysis in Radiance. 

Export to Radiance: Run Analysis 


Go to the Export Manager Panel > Select the RADIANCE/DAYSIM Button and choose Export Model 

DataS 

This will launch the Autodesk Ecotect – Calculation WizardSfor Radiance Analysis which will allow you to 

go through a multi step set3up the will define calculation type, general settings, sky conditions and where 

the light values should be calculated over. 

28

Radiance/Daysim Images: 

Illuminance image (Lux): Illuminance images are 

completely different as they represent the amount of 

light actually FALLING ON each surface. This means 

that the colour and reflectivity of the surface only 

affects the illuminance of objects around it, not its own 

relative brightness in the scene. As a designer, such 

images are invaluable as results are given in Lux and 

relate directly to minimum illuminance values given for 

specific tasks in lighting design guidelines and 

building codes. By default this information will be 

returned to Ecotect in a measurement of Lux. We will 

look to translate this information into footcandles for 

our use and will later show how to make this 

conversion (One footcandle ≈ 10.764 lux). 

Presentation of Results: 

Final Render: Generates fully rendered high quality 

images (If you intent to bring the Radiance data back 

into Ecotect you need to use the option). 

Open Radiance Control Panels: Displays the exported 

scene files in an external editor that allows you to 

view or change the raw code. 

Luminance Distribution: 

The distribution of light over the sky dome can change 

quite dramatically even within the space of a few 

minutes, mainly due to the formation of clouds. Thus, 

rather than try to accurately simulate any specific sky 

condition, representative sky models are used. 

Each type of sky is intended to be typical of a 

particular design condition. For example, on a typical 

summer day, the sky is likely to be clear and bright so 

a Sunny Sky should be used. On a winter day, the 

sky is more likely to be overcast, so a cloudy sky 

should be used. Per our LEED IEQc8.1 expectations 

we will choose to use the CIE Clear Sky Model 

(Sunny Sky Summer). 

Date and Time: 

Radiance uses the latitude, longitude and time zone 

of the site as well as the current date and time to 

calculate basic properties of its sky. Obviously for a 

sunny day this determines the position of the sun. 

However even for a cloudy day the date and time will 

affect the overall sky brightness. 

The 'Current Date and Time' option refers to the 

date/time currently displayed in the toolbar at the top 

of the main application window. 


29


Ambient Light Levels: 

What Type of Views to Generate: To accommodate ambient light levels, Radiance assumes some level of 

background illuminance in most scenes. It calculates this level automatically adding much more if it knows 

that the scene is outside under sky conditions. 

View to Generate: 

If you have set up one or more cameras within your model, you can use them to control views generated 

in Radiance Image Viewer. Within each camera's material properties, you can select different types of 

lenses to set up a range of different projections such as orthographic, cylindrical, fish3eye or perspective. 

Additionally, you can use the fore and aft clipping plane settings to create sectional views that allow you 

to look into a room or building without affecting the light. This can be advantageous when looking at post 

processes to the image, like overlaying contours or false color data (we’ll look at this more in the next 

section). 

Calculation Accuracy: 

As usual, the more accurate you want the analysis, the longer it will take. If you use the low setting, you 

may end up with very splotchy images and questionable results. Very high settings may mean waiting 

around for a week. There are no magic values, you will simply have to experiment. The variables you 

have control over are: Model Detail, Lighting Variability, and Image Quality. We typically leave the setting 

on Medium unless we are trying to capture an Image Quality from Radiance, then we will change form 

Medium to High. Be aware this will impact your Indirect Reflections setting. 

Saving To Radiance: 

As mentioned earlier these settings are extremely important when looking to understand where your RAD 

files are being saved to. A best practice for this is to define a location on your local machine as to avoid 

30


long file path names or names with spaces which may result in an error message from Radiance. This 

information can always (and probably will be moved) at a later date but this is an ideal starting location. 

Radiance Analysis Summary: 

Output Options: Be sure this option is set to Final 

Render and Generate Point Data is checked. You will 

also want to verify that Current 2D analysis grid is 

selected as well. 

As discussed earlier the only variation from this will be if 

you are looking to control your RAD file when using the 

Open Radiance Control Panels. If this is the case you 

will see “run in Radiance CP” in the output options. 

Scaling Factor: The model in Ecotect is always stored in 

millimeters, irrespective of the units used to generate it. 

Even though light is reasonably scalable, for accurate lighting calculations RADIANCE scene files should 

be generated with meters as their base units. Hence the default scaling factor of 0.001. However, the 

button to the right allows you to choose from a range of export units including feet, inches as well as 

millimeters. 

View Image when Done: This option is also only available when you run a Final Render. On completion 

Ecotect launches the RADIANCE Image Viewer to display the rendered views. You can then carry out a 

range of post processes to the image to overlay contours or false color data. 

Include Material Definitions: When checked, material definitions based on Ecotect material properties are 

included in RAD files. Only materials used by objects in the corresponding file are included. Here you will 

also want to make sure the highlight the “Check for Material.rad files” box. As discussed earlier this 

searches for a file with the same name as any material used in the Ecotect model and, if found, includes 

its contents in the output file instead of the simple Ecotect material definition. This applies to light 

definitions and surface materials. Ecotect first searches the same directory as the Ecotect model and then 

the Export Material Directory. Thus, if you wanted to include a RADIANCE definition of a 

GLAZING_NORTH_SOUTH material, simply place the RADIANCE material specification in a file called 

GLAZING_NORTH_SOUTH.rad and place it in either of these directories. 

Electric Lights: 

Turn Lights Off: Lights objects are not exported. This is used mainly for natural light studies. 

Indirect Reflections: This setting determines the number of surface reflections that are traced from each 

sampling point ray. Increasing this value increases the accuracy of the scene but also significantly 

increases calculation times. Values beyond 5 generally show diminishing returns, depending of course on 

the exact nature of the geometry (we typically set this to 2 or 3). 

Select OK to run Radiance Analysis. 

This will initiate a DOS prompt while RADINACE runs 

the analysis. RADIANCE will inform you of a warning 

that will read “Warning: This could take quite a while...” 

RADIANCE does not have a percent complete screen 

like Ecotect so you will have to be patient until the final 

rendered images appears in the Radiance Image 

Viewer (per our previous settings). 

31

Export to Radiance: Radiance Image Viewer 


Since we selected a specific camera view in the Calculation Wizard, when the Radiance Image Viewer 

first launches you will see a rendered image like the one below that has no additional data visible, but 

Radiance will allow you to view the results in a few different ways from this screen. One option is to left 

click on the rendered image to place a point reading for the view which will create a crosshair placed in 

the view with its illuminance value next to it. 

The Radiance Image Viewer also has a series of other ways to overlay information on the rendered 

images that have been created allowing for an overall 3D analysis view which Ecotect does not provide. 

You can choose to view the images with Contour Lines, Contour Bands, False Colour, Human Sensitivity 

and other overlay options by using the Information Overlay pulldown. Once a desired images type has 

been selected you can select the Apply Information Overlay button (the green triangle next to the units 

option) to view the results. 

You can choose to save these images out if you wish or you can always refer back to them in the folder 

that was defined when the “Select Output File and Check InstallationS” path that was defined in the 

Saving to Radiance tab of the Calculation Wizard. To do this from the Image Viewer you can go to the 

File pulldown and select Open ImagesS which will allow you to select one of the .Radiance Image Files 

(*.PIC) that have been saved in the Radiance output folder. From the File pulldown you can select Save 

Displayed Image AsS which will give you the chance to save the value as a JPEG, TIF, BMP or other 

image format. 

32

Export to Radiance: Radiance Import 

To capture this analysis information in the Radiance Image Viewer, we can 

always choose to import that data back into Ecotect. Because we chose 

“Generate Point Data” and “Current 2D analysis grid” in our output options, 

the Radiance Import dialog box will also appear on your screen. This Import 

Dialog will ask you to replace an existing data row of information in Ecotect. 

From here you can select a calculation that you are currently not using. 

Once you select Import the information will be brought in and you can use 

the settings in the analysis Grid Panel to modify the way your view reads. 

Analysis Grid Management 

Analysis Grid Panel 

Now that you have captured your illuminance analysis information from Radiance 

back into Ecotect you will need to be able to manipulate, view and analyze this 

information. The Analysis Grid Panel is where you will be able to do this. 

Changing Analysis Grid from Lux to Footcandles 

Although Ecotect does not do the conversion automatically, you can manage the 

analysis grid to show the illumunance values in foot3candles rather than lux: 

1. Click on Grid Management button, then select the Edit Grid Data tab. 

2. Type “V * 0.0929023” as the equation to apply to the grid data; this will 

convert your current Lux values (“V”) to foot3candles. Press Apply. 

3. Click the tab Manage Grid Data and make sure the Daylighting Level is 

selected, then edit the lux under the units column, to Foot3candles, then 

press “OK”. 

4. Now your grid may go back to all blue. Go ahead and reset the scale 

under Fit displayed values. 

5. Click OK or Close to exit. 

Your grid may not have the correct scale following the conversion from lux to foot3 

candles, but you can go to the Data & Scale section to adjust the Minimum, 

Maximum, and Contour variables. In our example we have set the Minimum to 10 

fc and the Maximum to 500 fc per LEED IEQc8.1: Daylight and Views – Daylight 


33


Another option of capturing information from Radiance is to save the analysis grid information for future 

use which can save a significant amount of time if you don’t have to re3run the simulations. To do this 

Ecotect gives the opportunity to both Export and Import the analysis grid information. 

Import and/or Export Analysis Grid Data: 

• Select Grid Management from the Analysis Grid Panel 

• Go to the Manage Grid Data tab 

• Select Export DataSwhich will save out a .txt file of the results 

• You can always go back and choose Import DataS 

• Select a previously exported .txt file to display on the analysis grid 

• Press Close not OK (sometimes it will clear the analysis grid) 

Note: It is also important to reset analysis grid after each simulation. 

Lastly, you will have the opportunity 

from this Grid Management dialog 

box to analyze the data in a report 

form. The data will be available in 

either a HTML format or an Excel 

spreadsheet. To do this you can 

select the Analyze Data button or go 

to the Reports Page which will give 

you more options to control the 

format and structure of the data you 

are capturing. 

Go to the Analysis Grid Panel 

Use the controls in this panel to set the display options of the grid. If the grid is displayed, changing any of 

these options will automatically generate redraw. 

Show Gridlines: Displays lines between each grid cell. 

Shade Grid Squares: Displays each grid cell as a color3filled block. The color corresponds to the scale 

shown in the top3right of the 3D Editor canvas. 

Show Contour Lines: Displays values as a series of contours over the grid. The range and increment of 

contours is given in the Grid Position group below. If Shade Grid Squares option is checked, the contours 

are shown as colored bands instead of lines. 

Clip to Minimum: When checked, points with values below the minimum value given in the Grid Position 

group below are not shown. 

Show Grid Axis: Displays a 3D axis around the grid with units. If neither the Show Gridlines or Shade Grid 

Squares options are selected, the axis shows the actual cell indexes in each direction. 

34


Show Node Values: Displays the numeric value currently stored at each grid node. 

• Peaks & Troughs: Displays the value at a grid node when all surrounding points are either higher 

or lower. On a relatively smooth grid this usually gives a clearer view than showing all node 

values. 

• Selected Only: Displays values only at grid points that are currently selected. See the Grid Nodes 

group for details on actually selecting individual nodes. This setting allows you to specifically 

choose the exact nodes at which point values will be displayed. 

Show Average Value: When checked, the average grid value is displayed in the bottom3left corner of the 

3D Editor canvas. This is simply the sum of all visible node values divided by the number of nodes 

summed. 

Show Values in 3D: Displays each point value with an offset based on its value and the current scale. 

This produces an undulating grid surface as opposed to a flat plane. 

Data Output Options: 

Export Images 

Along with being able to capture the report data you may also want to capture the graphics of the 

illuminance levels in the space for the documentation of LEED IEQc8.1: Daylight and Views – Daylight. 

To best capture this type of graphic, to submit to LEED Online, should be done in the Visualise Page. 

• Once you’ve set your model thresholds you can navigate to a plan view. 

• Go to the File pulldown > Export > Image/ScreenshotS 

• You can also use the Copy View to Clipboard Icon in the lower 

right corner of your screen. 

Either way this method will allow you to capture the appropriate images and set the resolution you need 

to export the image out as. These options will also be available to you in the 3D Editor Page but you will 

not be able to set a final image resolution resulting in a lower quality image. Another give and take with 

this process is that images exported from the 3D Editor Page will include point data, while images 

exported from the Visualise Page will not. 

Full Image Clip to Minimum (10 fc) 

35

LEED Credit Documentation 


While these images from Ecotect are showing the relevant information needed for LEED documentation 

they are not able to quantify the square footage totals and the percent of regularly occupied spaces that 

meet the minimum/maximum footcandle requirements as stated earlier in our document. To do this we 

will import this information back into Revit to quantify using area plans. Able to import a raster image you 

can easily use the area plans to trace over the areas that meet the minimum 10 fc threshold but do not 

exceed the 500 fc threshold. With area plans defining this information, schedules can summarize the total 

square footage numbers for the defining whether or not the regularly occupied space will meet the LEED 

IEQc8.1 requirements. 

Regularly Occupied Spaces Spaces Meeting LEED IEQc8.1 Thresholds 

Results: Baseline vs. Other Outcomes 

Baseline 

Throughout the course of this handout we highlighted a 

series of best practices/workflows in both Revit 

Architecture and Ecotect Analysis to optimize the 

accuracy of your simulations. Many of these examples 

were benchmarked against an accurate simulation run 

with the following criteria defined: 

• Summer Solstice @ 12:00 

• Sky Definition: Sunny with Sun 

• Glass set to single pane 

• Furniture On 

• RAD files used for all materials 

A series of iterative comparisons against these baseline 

conditions can be found in the course presentation. 

36


It is also important to keep in mind that while daylighting is complex there are a couple key items you 

should keep in mind when referring back to this handout and others from the Existing Building Power 

Track at Autodesk University 2011: 

• Daylighting is complex 

o Understand your BIM workflow to optimize the interoperability of the geometry you create 

o You need to leverage both Ecotect Analysis and Radiance to optimize outcomes 

o Understanding materials is key – Visible Transmittance and Surface Reflectivity 

• Daylighting strategies should be part of a larger integrated design process 

References: 

Book & Reports 

Heschong Mahone Group http://www.h3m3g.com/projects/daylighting/projects3PIER.htm 

Heschong Mahone Group 3 Daylighting & Productivity Executive Summaries http://www.h3m3 

g.com/projects/daylighting/summaries%20on%20daylighting.htm 

Designing a Quality Lighting Environment by Susan M. Winchip 

natural frequency RADIANCE & Daylight Factors http://naturalfrequency.com/articles/radiancedf 

For more information on Radiance materials 

Radiance Basic Tutorial http://web.mac.com/geotrupes/iWeb/Site/Tutorials_files/Basic%20tutorial%203 

%20Radiance31.pdf 

University of California Radiance Tutorial http://hobbes.lbl.gov/radiance/refer/refman.pdf 

Radiance Material Notes http://www.artifice.com/radiance/rad_materials.html 

Autodesk University 2010 sessions: 

ME23133P: Leveraging BIM for Energy Analysis 

Jessica Miller, TRO Jung|Brannen 

Autodesk University 2011 sessions: 

MP634003P: Rapid Energy Modeling to Evaluate Building Improvement Investments 

Oliver Riley, URS Scott Wilson 

MP61003P: Real3World Examples of Energy Retrofit Projects 

Lura Griffiths, Glumac 

MP60813P: Rapid Energy Modeling and Sustainable Design with Reality Capture 

Jessica Miller, TRO Jung|Brannen 

37


38

BIM for Advanced Daylighting - Autodesk Sustainability Workshop

Create successful ePaper yourself

Delete template?

Save as template?