pyro

[viezel]

hi, im doing a smoke render atm. I use the regular pyrofx shader and a spotlight with depth map shadows.

It takes 9 hours of rendering time to complete 180 frames of smoke (not even included the sim time). Its almost standard settings of the pyro shader, and I only have smoke visible, not fire or scattering.

Its really a basic setup, as you can see in the attached image.

How can I optimise the rendering, to make much less time?

thanks!

[Hazoc]

How can I optimise the rendering, to make much less time?

See your render settings under the Sampling tab. Volume step size parameter is never automaticly optimal. I think the default 0.1 is overly dense for your scene since you don't have any crispy noise details to catch. Try bigger values (between 0.1-1) and see when you reach good balance between speed and level of detail. Also 3x3 pixel samples may some times be to much.

[viezel]

Try bigger values (between 0.1-1) and see when you reach good balance between speed and level of detail. Also 3x3 pixel samples may some times be to much.

Uhh, great stuff Hazoc. Cheers! Its already much better! Any other great volume related rendering settings I could consider?

[Hazoc]

Uhh, great stuff Hazoc. Cheers! Its already much better! Any other great volume related rendering settings I could consider?

Under the Render tab theres "Opacity Limit". It terminates the ray marching process when given amount of opacity/thickness is reached. Lower values produce artifacts but again it depends on your scene what values are suitable. If you have fast camera movement etc. there's a good chance no one will notice. Or if you find that it's easy to fix these spots in comp.

Make sure your shadowmap isn't unnecessarily big and high quality.

Finally, pyro shader noises have their Octaves parameters. Make sure you don't spend time computing octaves that really have no visual contribution.

[viezel]

Under the Render tab theres "Opacity Limit". It terminates the ray marching process when given amount of opacity/thickness is reached. Lower values produce artifacts but again it depends on your scene what values are suitable. If you have fast camera movement etc. there's a good chance no one will notice. Or if you find that it's easy to fix these spots in comp.

Make sure your shadowmap isn't unnecessarily big and high quality.

Finally, pyro shader noises have their Octaves parameters. Make sure you don't spend time computing octaves that really have no visual contribution.

Cheers!! that works great.

[essencevfx]

I got another one thats a big time/ram saver... never raise your pixel samples on your volume renders above 3x3 ..this only applies to h11..h10 you'll sill need more samples = detail .

as well, change your volume filter on the geometry you're rendering from to something like Blackman , and lower the filter size to .7-.9 .. if you go to low on the filter size though, your renders will show voxel patterns ...but it can sharpen things up without the use of lower volume step ...there is always gridless advection, ( or rendertime displacement ) , but thats quite a bit more involved

ahh yes, and rendering out your deepshads as a separate pass then reading them off of disk will help if RAM becomes an isssue ( as it usually does at lower vol steps ..)

peace

jer

Edited April 7, 2011 by essencevfx