NURBS Surface Extra Attributes
The V-Ray Additional Attributes can be added to a NURBS surface shape node. This is done from the Attributes>VRay menu in the Attribute Editor with the NURBS surface selected. You can control the quality of the NURBS subdivision using these attributes.
Generate static geometry - when on, V-Ray will subdivide the NURBS surface into triangles before the actual rendering has begun. This allows the building of a faster BSP tree but takes more memory. When off, NURBS surfaces will be treated as dynamic geometry, similar to Subdivision meshes, and will be converted into triangles on the fly. This saves memory for other purposes, but may be slower.
Max tesselation depth - this parameter controls the maximum number of triangles that V-Ray is allowed to generate for this NURBS surface. Note that this number is proportional to the logarithm of the actual number of triangles, so you don't need very high values. Also if you want to lower the quality of the NURBS surfaces, it is better to do this by increasing the Curvature threshold parameter, rather than lowering this one.
Curvature threshold - decrease this parameter to allow V-Ray to subdivide the NURBS surface more, for a smoother result. Increase it for faster rendering and less RAM usage, but lower quality.
Allows you to give unique object IDs to your objects so that you can create selection masks using the "Multimatte" render element.
Allows the user to create their own attributes.