Cycles: implement smooth shaded self-shadows, eliminate Shadow Terminator Offset

Hi,

I am new to Blender, but have 30 years experience in 3D. Cycles seems like a great renderer, I've seen some amazing examples. But there is one very big problem I immediately see. Cycles does not respect smooth shading for the purposes of self-shadowing. The workaround is to increase the Shadow Terminator Offset, but this is a very poor non-solution because it is not optically accurate. We are forced to make the shadow creep over the surface to cover the problem. This changes the composition of the rendering. We must change the art to workaround a problem in the software.

I'm sure someone is going to make the argument that low polygon geometry is actually geometrically faceted, and therefore the blocky self-shadowing is not a bug, but a feature. But by that logic, all edge smoothing and vertex normals are bogus, normal maps and bump maps are not a valid way of working, and the only proper way to shade anything is to increase the polygon count to sub-pixel levels of detail. Obviously, this is ridiculous.

Moreover, Eevee does not have a problem with smooth-shaded self-shadowing. This is a case where the advanced path tracer lacks a basic feature that is implemented in the interactive renderer. Indeed, Cycles is the only renderer I have ever seen that has this issue, and I've used dozens of renderers.

This is a major limitation, and fixing it needs to be prioritized and dealt with immediately. Covering the problem by increasing the Shadow Terminator Offset is not a solution.

Thank you,

Aaron F. Ross