Blending displacement materials

[FlynnAD]

I'm trying to use a Vray Blend Material to blend two other Vray Materials, each with their own bitmap displacements. It seems that the Vray Blend Material only takes the displacement from the base material and ignores any coating materials' displacements. Even if I turn off the displacement checkbox of the base material, the Blend material does not use any displacements of the coat materials.

Is this really the case or am I doing something wrong? It seems that the Blend material would blend displacements in the same way that it blends color, specular, etc.

In the forums, these posts are close, but do not give an answer for this issue:

https://forums.chaosgroup.com/forum/...r-displacement

https://forums.chaosgroup.com/forum/...h-dispalcement

Screenshots are attached as well as a sample file if you want to test it out.

Thanks,
Matt

[matanov]

You should blend the textures first and then put the result in the displacement slot of the material (or VRayDisplacementMod).

[FlynnAD]

I understand that's possible (to pre-blend the displacement bitmaps, then only add that one blended bitmap to the first material only, and no displacement to the second material at all), but isn't this just a work-around for how it ought to work?

It gets harder if the two original materials do not have the same amount of displacement. If material A was displaced 12.5 and material B was displaced 3.7, then the user has to manually tweak and find the correct amount of blending within the composite-bitmaps to get the intended result with only a single displacement map. It may be that bitmap A has to be the base at 100%, with bitmap B blended 29.6% or something. And later, if the user wants to just increase the displacement of bitmap A, then the material's displacement number has to increase, and the composite blending amount has to decrease. That seems laborious and prone to error.

Has no one asked for this option before?

Thanks,
Matt

[MANUEL_MOUSIOL]

Are there any plans to make this easier?