Looking for some quick/obscure pointers on how to speed up rendering in Iray

simpsonDDS2

Rendering individual models is reasonably quick and looks incredible, but rendering an entire scene increases the time taken by alot.

I'm just looking for a big list of things that will help speed up rendering in Iray while maintaining decent visuals.

The pointers I have so far are -

1. Render scene instead of Dome and scene (can't do that because it leads to a pixel glitch)

2. Something about changing everything in the scene to the Iray shader? No idea how to do that though.

3. I've turned on both CPU and GPU rendering alongside that speed up rendering option, no idea if any of these make a difference though.

That's about it. Thanks to anyone who answers in advance though.

Richard Haseltine

1. The pixel glitch sounds like the issue with Chromatic SSS in the version of Iray in the current release build - DS 4.11.x.x (the current public beta) has a fixed version of Iray. However, I would not expect scene lights to be faster than the dome (for a non-interior shot at least) in any event.

2. This may save upload time (from DS to Iray) but won't affect render speed as DS does it anyway if you don't.

3. Are you sure the GPU is being used - I suspect that the scenes are exceeding its memory cpacity, which would throw you back to CPU and so slow the process down.

One option is to try reducing texture sizes, or even to simplify the materials on more distant items. There's a free script for texture reduction, or there are a couple of store products that can help:

https://www.daz3d.com/scene-optimizer
https://www.daz3d.com/resource-saver-shaders-collection-for-iray

simpsonDDS2

Richard Haseltine said:

1. The pixel glitch sounds like the issue with Chromatic SSS in the version of Iray in the current release build - DS 4.11.x.x (the current public beta) has a fixed version of Iray. However, I would not expect scene lights to be faster than the dome (for a non-interior shot at least) in any event.

2. This may save upload time (from DS to Iray) but won't affect render speed as DS does it anyway if you don't.

3. Are you sure the GPU is being used - I suspect that the scenes are exceeding its memory cpacity, which would throw you back to CPU and so slow the process down.

One option is to try reducing texture sizes, or even to simplify the materials on more distant items. There's a free script for texture reduction, or there are a couple of store products that can help:

https://www.daz3d.com/scene-optimizer
https://www.daz3d.com/resource-saver-shaders-collection-for-iray

Do you have a link to the free script, and how to actually implement it? Thanks!

FSMCDesigns

simpsonDDS2 said:

Richard Haseltine said:

1. The pixel glitch sounds like the issue with Chromatic SSS in the version of Iray in the current release build - DS 4.11.x.x (the current public beta) has a fixed version of Iray. However, I would not expect scene lights to be faster than the dome (for a non-interior shot at least) in any event.

2. This may save upload time (from DS to Iray) but won't affect render speed as DS does it anyway if you don't.

3. Are you sure the GPU is being used - I suspect that the scenes are exceeding its memory cpacity, which would throw you back to CPU and so slow the process down.

One option is to try reducing texture sizes, or even to simplify the materials on more distant items. There's a free script for texture reduction, or there are a couple of store products that can help:

https://www.daz3d.com/scene-optimizer
https://www.daz3d.com/resource-saver-shaders-collection-for-iray

Do you have a link to the free script, and how to actually implement it? Thanks!

see this thread https://www.daz3d.com/forums/discussion/137161/reduce-texture-sizes-easily-with-this-script/p1

 

Paradigm

Render it at a higher scale for a shorter period and scale it down. For example render at 4k for 5 minutes and scale down to 1080p instead of rendering at 1080p for 10 minutes. I made the times up, but the point is you can render for a shorter period of time at a higher scale and get similar results. There's obviously deminishing returns.

Also, in 4.11 there's a post denoiser that converges scenes VERY quickly if you're OK with some blurriness. I've seen about a 9x reduction in render times using it since my usecase isn't super crisp renders and I can handle a level of softness in the final product.