PI-VR - VRED Professional 4.2 - PI-VR GmbH

VRED Documentation
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Ambient Occlusion
In VRED the Ambient Occlusion Calculation is a
preprocess and takes place during the data
preparation. The calculated Ambient Occlusion results
will be baked on the geometries vertices. The
smoothness of the Ambient Occlusion depends on the
level of detail of a geometry. Therefore VRED offers
several ways to increase the quality on low level
geometries, like subdividing triangles and predefined
quality presets.
Ambient Occlusion is a sophisticated calculation
method which simulates soft global illumination by
faking darkness perceived in corners and at mesh
intersections, creases, and cracks, where light is
diffused (usually) by accumulated dirt and dust. This
has the effect of darkening cracks, corners and points
of contact.
Ambient Occlusion is a specific not-physically-accurate
rendering trick. It basically samples a hemisphere
around each point on the face, sees what proportion of
that hemisphere is occluded by other geometry, and
shades the pixel accordingly. Its got nothing to do
with light at all, its purely a rendering trick that
tends to look nice because generally in real life surfaces that are close together (like small cracks) will be
darker than surfaces that dont have anything in front of them, because of shadows, dirt, etc. The Ambient
Occlusion process though is approximating this result, its not simulating light bouncing around or going
through things. Thats why Ambient Occlusion still works when no lights are in the scene.
Important: Only selected Objects will be calculated. All other visible Objects in the scene are taken into
account.
Presets: Loads and saves Ambient Occlusion presets. Additional presets can be added or removed
Global Illumination --> Shadow Quality: Defines the direct shadow quality of the Ambient Occlusion.
5 Presets are Available:
- Preview Quality
- Low Quality
- Medium Quality
- High Quality
- Highest Quality
Min Distance: Sets the minimum distance where objects will be taken into account for the Ambient
Occlusion calculation. This value defines total black areas where full occlusion takes place.
Max Distance: Sets the maximum distance where objects will be taken into account or the Ambient
Occlusion calculation. This value defines total white areas where no occlusion takes place.
This value can also be seen as the maximum expansion of the virtual hemisphere.
All numeric values represent mm as units.