Using 3D layer masks.

Guys,im curious about the rendering a layer using other layer as a mask.
I have a object in layer 1 of 3d viewport and other object in 2nd layer.Now,in render layers i on layer 2 as mask of layer 1.
so now to render with mask blender renders layer 2 also but i just want to use the alpha of layer 2 and dont waste time in rendering mesh in that layer…is there anyway? :frowning:

Hi,
I want to use layer 2 as mask of layer 1.so in Render layers i made layer 2 on in masking of layer 1.
Now,problem is that blender is rendering layer 2 also instead of using it for just masking…I want to save time by not rendering the mesh in layer 2…is it possible? :frowning:

You have to render layer 2 to determine how it masks things. Now, if you don’t have any transparency on layer 2, you can set the layer material override to some simple dummy material, that should speed up that layer a bit. If you’re using Cycles, you can also use per-layer samples to cut things down, something like 10-20 samples is probably enough for a mask-only layer unless it contains a lot of fine details. All of these settings can be found in the layers tab.

Easy: See that little box that says “Solid”? Uncheck that box on your mask layer. The geometry won’t render but it will still be used as a mask in the other layer. It doesn’t use the alpha of the mask layer, it uses the z-buffer of the geometry to create the mask.

Edit: For some reason the image isn’t showing up properly unless you right click and select “View Image”.

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Ok…from ur reply i come to know you cant avoid rendering the mask layer at all…but we can cut the time by working on what it renders.
but can you please help me by showing me how to use or create material override,just a guide and will then research that…this will help me a lot.
Thanks a lot :slight_smile: