In Rhino V6, even if we can’t seem to apply custom mappings to different surfaces to a polysurface or an extrusion without first expoding it–we can apply different materials to their surfaces.
As we make things such as buildings, often there are surfaces which will never be seen. Drawing them is often pointless. Though, renderers may need to know that the object surface is still tangible and solid.
If a NoDraw materials is employed, it could increase realtime raytracing and raytracing by perhaps 10% on buildings. It also solves problems caused by Z-fighting in surfaces that come close to being co-planer, such as a radius, blends into a corner. It would also eliminate concern that by placing a 2mm vinyl floor over the floor that there would be rendering problems.
(It would not eliminate Decals, because likely use a stand-off and are likely put on on in a later pass.)
A NoDraw material could even increase preview performance. There could be a toggle to show or not show the surface marked with NoDraw. In use, the No-Draw material would be applied, lastly, and poof, that surface would become unseen, and not slow down the preview renderer. When it’s seen, the NoDraw material would be a simple 1-pass texture, with limited rendering requirements. It would need multi-pass environment maps, or reflections, or optionally even lighting effects.
Lastly, depending on the raytracer, it might be possible to save memory by eliminating meshed surfaces marked with a NoDraw materials all together.
There might even be an appropriate material type that can do this, but as a user, I have no idea which one would work in a beneficial way across all the renders. For instance, one of Rhino’s raytracers uses BSP’s, so it would have to be a material type that won’t interfere with all it has to do.
The user would select any surfaces that aren’t seen, and apply the NoDraw material. If you are showing house framing, you don’t need to see the bottom of the 2x4’s. Because of Rhino3D’s excellent snaps, you could resize the studs without even needing to toggle the NoDraw back on.
This is not new tech, it is 20 year old gaming tech, but to bring it to a CAD modeler, would be revolutionary. When I was doing level editing, I would have loved to have Rhino’s 3D tools.
[In games the standard no-draw material/shader it was simply called: “Caulk.”]