Rendering in SketchUp

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Part 5: The Iterative Rendering Process
Fig. 19.12: 
Each vertical line represents a tree that will be instanced and replaced with a 3D detailed tree com-
ponent when rendered (SketchUp model).
Fig. 19.13: 
The vertical lines are replaced and rendered with a 3D tree. Twilight instances the tree, allowing 
very large models to be rendered (Twilight Render).

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Chapter 19: A Rendering Overview
Proxy rendering
Proxy rendering allows you to place a component into the model as a placeholder. The placeholder 
is then linked to another component not in the model. The linked component is rendered, not 
the component in the model.
The feature is ideal when you’re working with 3D vegetation. You can place 2D Face Me veg-
etation components in the model and then link the 2D components to 3D versions. When ren-
dered, the 3D vegetation will be displayed, replacing the 2D vegetation. This helps maintain 
SketchUp and computer performance (Fig. 19.14, Fig. 19.15).
Instancing and Proxy rendering
Instancing and proxy rendering are very different. When you’re proxy rendering, each 
vegetation component must still be processed. For example, if there are ten trees in the 
model, the 3D versions of those ten trees must still be processed by the IRP. This means that 
face-count limitations and the amount of RAM will affect the length of time the IRP takes 
to render. With many proxy models of vegetation, the IRP can run out of RAM before the 
rendering is finished.
In contrast, instancing can have just as many trees; however, the IRP will process only one of 
the 3D trees. Any identical components will be instanced and not processed by the IRP. Thus, 
the instanced tree does not max out the RAM limitations or affect rendering times.