optimizing pyro/billow smoke rendering times.

[anupamd]

Guys, Im finding that the billoweysmoke and/or pyro shader is really...really slow. Is there any tips or trick to optimizing the rendering times? Like any settings for lights/mantra?

Currently I have 3 shadowing spotlights with 256x256 dmaps.

Any tips or advice or things to look/test would be appreciated. At this point Im kind of at a standstill.

-A

[lukeiamyourfather]

Try a larger volume step size (parameter on the Mantra driver).

[Eitht]

I believe pyro shader has a "Scattering" checkbox which was switched on by default, turning that off will help a lot!

eitht.

[anim]

definitely look at volume step size as lukeiamyourfather said since that is dependent on your scene size so default value for large scene would be overkill

you can compute the minimum value by dividing size of your volume grid in one dimension with number of voxels in that dimension

then you can increase it to get faster render times at slight quality loss then you decide if it's still acceptable

for billowy smoke you may want to turn off noise since it may produce some stretching artifacts because it uses just single rest attribute

billowy smoke is faster than pyro shader from my experience so if it's good enough for you stick with it

for better quality you may need to increase resolution of your dsmaps but maybe consider turning off shadows on some lights, sometimes one shadow casting light is enough

[smaugthewyrm]

andreu lucio makes some adjustments to the billowy smoke shader and uses vopcvex / geovexvolume to render clouds.

to me they appear to render much faster. you would have to try it and see for your self.

he walks you through the workflow here:

cmivfx fractal clouds & terrains

[bunker]

Mantra is really fast at rendering volumes, but the pyro shader

is really slow indeed. You should have a look into doing your own shaders

Guys, Im finding that the billoweysmoke and/or pyro shader is really...really slow. Is there any tips or trick to optimizing the rendering times? Like any settings for lights/mantra?

Currently I have 3 shadowing spotlights with 256x256 dmaps.

Any tips or advice or things to look/test would be appreciated. At this point Im kind of at a standstill.

-A

Edited July 29, 2011 by bunker

[nahee]

Mantra is really fast at rendering volumes, but the pyro shader

is really slow indeed. You should have a look into doing your own shaders

Hey Julien, do you have an example vop (or otherwise) shader handy by any chance? A sort of a reusable fast volume shader.

And everyone else: any pointers to some fast volumetric mantra workflows/shaders would be great, thanks!

[Erik_JE]

Hey Julien, do you have an example vop (or otherwise) shader handy by any chance? A sort of a reusable fast volume shader.

And everyone else: any pointers to some fast volumetric mantra workflows/shaders would be great, thanks!

I would suggest looking at the basic flame and basic smoke shaders. They are way faster than the pyro shader.

[nahee]

I would suggest looking at the basic flame and basic smoke shaders. They are way faster than the pyro shader.

Indeed they are. I was hoping there was a way to make the Billowy smoke shader a bit faster. Will definitely check out the "Fractal Clouds" cmivfx tut as per smaugthewyrm's suggestion.

Thx

[Macha]

I think the standard mantra volumes render fastest with the raytracer; it is also the one that's easiest to scale up on more cores. See if you can get away with a different setting for shadow volume stepsizes. Your shadowmaps don't need to be very big. Put some blur on it. Re-use them. Increase shadow pixels samples a little (2 or 3)

[Ratman]

You should also look into the volumevoxeldiameter() expression for your volume step size.