Most Efficient Way to Make a Decal in a VRayBlend Using VRayHDRI

[Joelaff]

Say I want to put a decal on using a VRayBlendMtl (because this makes it easier and clearer that the decal has a different material form the base... I often do this with different maps for each channel in a single VRayMtl, but that is more complex, and harder to "Read").

I can set the VRayHDRI to use the alpha channel as the mono output. This works for things like Opacity. However, it seems that the Blend input to VRayBlendMtl takes the color info for the blend. So I use a Color Correct (the third party one) to copy the alpha to the RGB channels.

Is this the easiest, most efficient way of doing this? I would rather not copy the VRayHDRI node for speed/memory, and adjustability issues. (Will VRay load the bitmap just once even if the different VRayHDRI nodes have different settings? I am guessing yes, but I don't know.)

[bmcaff]

I can't say if there is a better way but this is exactly how I have been doing it, including the 3rd party CC although the native CC works as well. It would be nice in the Max slate editor if you could pull out the different RGBA components instead of just the final output, like you can in Maya.