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In general, subdivision = surfaces have many advantages but sometimes you actually need a polygon= mesh.
Suggested reading:
Use creases to make sharp or semi-sharp edges without adding extra e= dge loops.
We selected all the edges of an isocahedron and animated their crease va= lue from 0.0 to 5.0.
All edges can have different crease values and still keep smooth transit= ions accross the final surface.
Corners work like creases for vertices.
In this animation, 3 edges of a triangular= face have a crease value of 5.0.
We increase the triangle's vertices corner values from 0 to 5.0.
Note the very smooth transitions around the tightened areas.
If you are coming from another renderer where you have to set subdivisio= n levels, forget about it: tesselation of surfaces is automati= c in RenderMan (we call it dicing).
The main control is the micropolygon length.
We compare a creased displaced catmull-clark subdivision surface with an= equivalent polygon mesh.
Increasing the micropolygon length is equivalent to making the object's = size smaller in the image.
Micropolygon Length works a bit like an "automatic leve= l of detail" and preserves memory when an object is so small in screen that= it doesn't need an fully detailed representation.
Notice that the subdiv degrades to a much lower number of faces, = preserving memory and speeding up raytracing.
This is what we call Data Amplification, when a compact= geometric representation can be augmented to create more detail on demand.=
Often, it is better to rely on displacement and bump mapping to add deta= ils.
If you have modeled a highly detailed object in ZBrush, you should consi= der:
extracting a displacement map from the high-resolution mesh.
Our displacement nodes have a "model displacement" input to connect the = extracted displacement map.