Here are the results of me experimenting with Cycles Render Passes, the idea is to selectively blur only those passes affected by noise, leaving the color passes unaffected by the blurring:
Notes:
- Render time for this was around 21 minutes on a six-core Phenom II at 2.8Ghz at a resolution of 2880 x 1620 at 200 samples
- This works best for diffuse/glossy materials with an image texture in the color channel
- This likely does not work well in conjunction with bump mapping
- It would be advisable to use seperate render layers for sharply and less sharply reflective materials, as the former ones suffer more from the blurring
- It is more efficient to combine the Direct/Indirect passes before blurring if the same blur is applied (like in this case)
- The caustics do not seem to be seperable through a pass, so they where not filtered and still appear as little dots throughout the image
Edit: I’ve been wasting too much time now trying to add in the .blend file. Seems like there is a 3 file upload limit but you only get the actual error message under some mystic circumstances… so here is an ephemeral pasteall link:
http://www.pasteall.org/blend/11213