Arnold for 3ds Max Forum
Rendering with Arnold in 3ds Max using the MaxtoA plug-in.
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Is it faster to render matte holdouts?

Message 1 of 8
438 Views, 7 Replies

Is it faster to render matte holdouts?


If I need to rerender just an element of an animation (the hair), what's the best/fastest strategy? 

If I create a render layer where everything but the hair is an holdout matte, will it render faster or the holdouts will have no difference on the render time?

If so what's the best strategy?


Labels (2)
Message 2 of 8
in reply to: giandosopaolo

The standard_hair shader supports ID AOVs.

Lee Griggs
Arnold rendering specialist
Message 3 of 8
in reply to: lee_griggs

Hi Lee, thanks for helping. 🙂

Yes, I am adware of that. My question than would be, if that is the fastest way to re-render a single element of a render sequence, in terms of render time. 


Message 4 of 8

If all you are needing to change is the shading on the hair, then rendering it as its own layer and comping the separate layers together will be faster. However once you start changing animation/geometry then you won't really get much in the way of savings since you'll have to re-render the background with the holdout matte changes.


Message 5 of 8

@lee_griggs @Yes I just need to change the shader and rerender them with higher samples

My doubt is, if I rerender it as its own layer with everything else set to a blackmatte, won't arnold still have to calculate the environment and other objects internally for determining their reflections and GI contribution on the hair? Won't then the render take the same time as before?

Message 6 of 8

You are correct that the shading/lighting on the hair will have to trace secondary rays into the rest of the scene to determine illumination. What you are saving is the primary rays that hit the background and the secondary rays that those hits generate.

Message 7 of 8


Given that, will there be an increase in render speed or not? 

Message 8 of 8

In theory yes you should see an increase in speed, but it's difficult to quantify exactly what speedup you might get.

Can't find what you're looking for? Ask the community or share your knowledge.

Post to forums  

Technology Administrators

Autodesk Design & Make Report