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Please forgive me if I'm wrong about this (because I probably am!), but when creating a matte-shadow pass with a light that has a texture (for example a vraySoftBox), the texture should only affect the colour of the light, and not the shadow (matteShadow) passes?
I have a light with a vray softbox that I'm trying to render a seperate shadow pass of the character shadows on the environment bg geo. Because I have a vraySoftBox texture, even when I have no shadowcasting objects in the scene, my matte-shadow element shows that shadows are being cast. I worked out that the shadows were being cast by the light itself (the texture). Surely the texture should simply affect the brightness/colour of the rays cast, and leave the shadowing untouched? The way it is, and I am probably wrong on this, it means that the shadow strength is being halved when comped due to the duplication of the texture in both the lighting (vrayShadow pass) and the alpha (vray matte pass).
If this is the correct behaviour, then I'm obviously not comping these passes correctly, so can you confirm the correct way I would isolate and comp a pass that I want to use to place the character shadows over a previously rendered BG plate.
From top to bottom layers :
Pass 1: Character, no BG, alpha is simply the character with the BG geo as matte, alpha -1, no affect shadows.
Pass 2: Shadow pass with only the shadow of the character on the BG geo. I assume to use the vrayShadow pass (for RGB) and matteshadow (for alpha). I would take this premulted pass in nuke and merge 'minus' to introduce shadows.
Pass 3: BG plate only. Character non-visible, and non shadow casting.
Thanks for any assistance.
p.
I have a light with a vray softbox that I'm trying to render a seperate shadow pass of the character shadows on the environment bg geo. Because I have a vraySoftBox texture, even when I have no shadowcasting objects in the scene, my matte-shadow element shows that shadows are being cast. I worked out that the shadows were being cast by the light itself (the texture). Surely the texture should simply affect the brightness/colour of the rays cast, and leave the shadowing untouched? The way it is, and I am probably wrong on this, it means that the shadow strength is being halved when comped due to the duplication of the texture in both the lighting (vrayShadow pass) and the alpha (vray matte pass).
If this is the correct behaviour, then I'm obviously not comping these passes correctly, so can you confirm the correct way I would isolate and comp a pass that I want to use to place the character shadows over a previously rendered BG plate.
From top to bottom layers :
Pass 1: Character, no BG, alpha is simply the character with the BG geo as matte, alpha -1, no affect shadows.
Pass 2: Shadow pass with only the shadow of the character on the BG geo. I assume to use the vrayShadow pass (for RGB) and matteshadow (for alpha). I would take this premulted pass in nuke and merge 'minus' to introduce shadows.
Pass 3: BG plate only. Character non-visible, and non shadow casting.
Thanks for any assistance.
p.
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