Normal map into displacement slot

[FlynnAD]

This might be a ridiculous question, but can you plug a Normal map into the Displacement slot of a vraymtl? I mean, obviously you can, but will it work "properly"?

What I've found is that since normal maps have their "base" level at 128,128,255 RGB, and displacement maps have their "base" at 0/ black and not 128/ mid-gray, then the base level of a normal map displaces your object where you expect no displacement to occur. Basically everything but your lowest grooves in the normal map are displaced outwards.

I kind of figured that since normal maps have more information through their color than regular black-and-white bump or displacement maps, that you would theoretically be able to use them likewise in a displacement slot. But it does not seem so, at least without lowering the normal map by -128,-128,-255 (which would destroy the map anyways).

Is this correct or is there another conversion node that I am not aware of?

Thanks,
Matt

[Deflaminis]

8 bit displacement maps have their base at 0, but 16 and 32 bit at 128. As I understand it.

[FlynnAD]

8 bit displacement maps have their base at 0, but 16 and 32 bit at 128. As I understand it.

Can someone verify this? I tried making a 16-bit normal map, saved as a .tif, but when that normal map was loaded into the VrayHDRI loader, then into a Normalbump node, then connected into the Displacement slot of a Vray material, the "neutral" purple still displaced the surface just like an 8-bit neutral purple normal map did.

Does the normal map need to be saved as an exr in order for neutral purple to be considered zero displacement?

Or are you forced to create a different black and white map for displacement, with normal maps only being properly used as a normal bump map?

Thanks,
Matt

[Ihno]

The normal map dosn't contain height information but angle information. I don't think there is a way to get this to work properly.
XNormal has a tool to convert normal maps to cavity maps (thin AO) and those maps can maybe work as height map in some cases.
I don't think there is a way to convert normal maps to properly working vector displacement maps.

[vlado]

What Ihno said... it won't make sense to plug the map directly for displacement.

Best regards,
Vlado

[FlynnAD]

I thought it made sense in theory, but couldn't get it to actually work. Thanks for confirming.

[oglu]

using only the blue channel does work sometimes... but its far from being a real solution...