V-Ray for Rhino Manual - Rum

Mesh Settings
In order for geometry to be rendered, whether it be with V-Ray or in the veiwport, a mesh needs to be created.
Because Rhino uses NURBS instead of meshes for modeling all of the NURBS geometry must be converted to
meshes in order to even appear in the viewport. The good part about using NURBS is that a different mesh can be
created from the same geometry; one which is very fine or another which is course
Setting a Custom Render Mesh
Access Render Mesh settings by clicking on Rhino Options and
under Document properties clicking on Mesh. By default Rhino
uses the preset Jagged & Faster. While your are working on
your model it is recommended that you use the Jagged & Faster
preset. However, when it becomes time to do render final
images the Jagged & Faster preset may not produce a fine
mesh, which can lead to odd looking renders.
To set a custom mesh click custom and the options below will
become active with whatever were the previous mesh settings.
The most effective way to create a mesh is by defining only a
few of the parameters and letting Rhino figure out the rest.
First change all of values to 0 except Maximum distance, edge to surface which should be set close to the
tolerance value for your scene. Now set one of two different parameters, Maximum angle or Maximum Edge
length. The best setting for Max angle is usually somewhere between 6 and 12. Maximum edge length will
depend on your scene, and usually works well for high detail scenes without many large flat surfaces, such as
jewelry. Beware of setting too fine of a mesh as this may take a long time for Rhino to calculate. Below are two
examples with the mesh on the left and the rendered result on the right.
The images above are from a very course mesh. Notice how the handle and the rim of the cup look jagged and odd.
The images below are from a very fine mesh. Now the cups appear completely smooth.
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V-Ray for Rhino