Architectural_Design_with_SketchUp

Chapter 6 Creating Geometry Using Ruby Scripting
.interpolate .inverse .invert!
.new .origin .rotation .scaling
.set! .to_a .translation
.xaxis .yaxis .zaxis
Although this (and the online documentation) might appear a bit confusing, let’s look at
just a subset of the available functionality. This provides enough functionality for what we
want to do. The relevant methods are these:
# Point Transformation—use for placing objects
t1 = Geom::Transformation.new( point )
# Translation Transformation—use for moving
t2 = Geom::Transformation.translation( vector )
# Rotation Transformation—use for rotating
t3 = Geom::Transformation.rotation( center, axis, angle )
# Scaling Transformation—use for scaling
t4 = Geom::Transformation.scaling( center, scale )
t4 = Geom::Transformation.scaling( center, xscale, yscale, zscale )
As you can see, they all use perfectly understandable parameters. If you want to move
something from location A to location B, then the vector between those points (expressed
as “go m units in the x direction, n units in the y direction, and o units in the z direction”) is
enough information to get it there. And if you want to rotate something, SketchUp needs to
know about which point you want it to rotate, about which axis you want it to rotate, and
by how many degrees it should turn. Finally, the scaling translation accepts either a uniform
scale or different scale factors in each coordinate direction.
In order to use these transformations, you need to add them as parameters to appropriate
methods. There are various approaches to this: Use transform_entities on the model’s
Entities collection as a universal approach. You can also directly apply a transformation to
groups or components, especially when you place an instance of a component (the transformation
describes the insertion point in that case).
Let’s look at this in action in a short code snippet. Select an object in your model (if you
select multiple, only the first gets used). Then paste the following code into the Ruby Code
Editor and click Run Code:
# Test transformations on selected object
mod = Sketchup.active_model # Open model
ent = mod.entities # All entities in model
sel = mod.selection # Current selection
# Get the center of the selected object
center = sel[0].bounds.center
259