PDA

View Full Version : Volumetric AA issue (LW 10.1)



Chrusion
08-15-2011, 09:00 PM
When Volumetric AA (for 120K HV volume particles) is enabled, render times go stratospheric with 4-pass, dithered MB at AA=1, and threshold=0.3 at a frame rez of 1280 x 720.

That is, without Vol AA, a frame with around 40 - 50K particles visible takes 13 minutes on a quad core i7 (3.2 GHz). On a dual Opteron 252 (2.6 GHz) it takes at most 45 minutes without and over 8 or 9 HOURS with!

I can live without AA'd dusty particles, but apparently with Vol. AA off, the particles don't motion blur either (perspective camera). Not even stepped or banded MB. Why?

I'd rather have "stepped" or "banded" motion blurred particles that aren't AA'd rendering at 15 min/frame than smoothly blurred particles that take 10 times longer to render. 8 hrs a frame is ridiculous for the meager amount of particles in view that are being ignored by radiosity rays.

Any workarounds/ideas?
.

Sensei
08-15-2011, 09:22 PM
Double resolution, don't use AA, then resize to original size in Photoshop.

Chrusion
08-15-2011, 09:34 PM
Like I said, I can live with the crispier, un-AA'd HVs. Rendering at double rez will take 4x longer and doesn't answer the question of why HV particle motions aren't blurred when MB is on (4 passes dithered) and Vol AA is off.

One would expect there to be 8 banded steps of the HV motion that would integrate into a smoother result than what's currently happening of NO sub-frame HV movement and thus a crisp "single" HV at each particle location.
.