unlimited resolution subdivsion surfaces at render time

[JeremyHowdin]

Hello -

I was wondering if it was possible to include unlimited resolution subdivison surfaces at render time - like renderman. So no matter how close the camera is to geometry a compound curve interpolation is automatically calculated to get a smooth result. Particularly good for organic objects with a camera move that goes close to far. The render automatic calculates how much curve interpolation is needed depending on how close the object is to camera. i.e. if the object is far from camera it needs less calculation than if it's near camera. A very powerful enhancement I think -

[cpnichols]

Renderman's method of doing infinite resolution is not quite correct. What they do is Micro-Polygons. This is controled via the shading rate. A shading rate of 1 means one polygon per pixel. A shading rate of .5 (typical) mean one polygon per half pixel. They use shading rates combined with the pixel samples controls everything from texture sharpness to AA.

Vray doe not work that way. It shoots rays. So, for example, when it does displacement, you are not looking at polygons (to the best of my knowledge). You are looking at a form of primitive.

[vlado]

Re: unlimited resolution subdivsion surfaces at render time

Hello -

I was wondering if it was possible to include unlimited resolution subdivison surfaces at render time - like renderman. So no matter how close the camera is to geometry a compound curve interpolation is automatically calculated to get a smooth result. Particularly good for organic objects with a camera move that goes close to far. The render automatic calculates how much curve interpolation is needed depending on how close the object is to camera. i.e. if the object is far from camera it needs less calculation than if it's near camera. A very powerful enhancement I think -

Yep, it is possible, although the implementation is very tricky. The new displacement system in the next builds of VRay does a similar thing by subdividing triangles based on their distance from the camera. It is possible to implement subdivision surfaces as well, although implementing this in a ray tracer is far more difficult than in a REYES-style renderer like PRMan.

Best regards,
Vlado

[JeremyHowdin]

Thank you for your reply Vlado -

Now I know its possible where do you think it sits in the priority list? If it reduces render times - i.e. particularly if it was to work in conjunction with displacement - on a character that was running towards camera or a camera moving far to close on some tubing. Do we think this is a valuable enhancement?