Nice Displace Feature that unfortunately breaks the Material

[gordon_heinrichsruscher]

Hi all,

so when you create a Material in (for example) Substance Designer and you have a heightmap + normalmap. You can´t recreate that Material using the VrayDisplaceMod.
Think about it. It even says it on the offical Documentation: "Note that V-Ray also automatically generates a normals map based on the displacement map to compensate for details not captured by the actual displaced surface."

So if you plug in your normalmap you essentially double your normalinformation. There is no way of keeping explicit normals (like in the turbosmooth modifier), then displacing it using the height map and then using the normalmap in the material.
What you simply get is too much distorted normals. Also.. you can´t always just leave the normalmap out of the shader, there might be extra stuff not included in the heightmap.

[gordon_heinrichsruscher]

some examples:

[^Lele^]

Hi all,

so when you create a Material in (for example) Substance Designer and you have a heightmap + normalmap. You can´t recreate that Material using the VrayDisplaceMod.
Think about it. It even says it on the offical Documentation: "Note that V-Ray also automatically generates a normals map based on the displacement map to compensate for details not captured by the actual displaced surface."

The part where it creates a normal map is for when the map detail is smaller than the edge length (think an ocean surface displaced to the horizon.).
That isn't the case in your example.

So if you plug in your normalmap you essentially double your normalinformation.

Not at all.

There is no way of keeping explicit normals (like in the turbosmooth modifier), then displacing it using the height map and then using the normalmap in the material.

Of course there is. The displacement modifier has a subdivision mode, optionally with CK mode.
That will behave exactly like turbosmooth plus displacement, for order of operations (and results, if the max mesh has matching details).
You won't need it, in your case, however, as the 3d displacement works just fine.

What you simply get is too much distorted normals.

The samples you posted show nothing of the sort.
Rather, it looks like the displacement map has a gamma applied (notice the curvature is stretched towards the whites at the top.)
Use a vrayBitmap loader, and set the gamma to none.

I may be wrong on a few counts, however, as it's impossible to say without seeing the scene as you set it up.
the attached image has the setup i mentioned, and the displacement height is set to 2cm (some arbitrary value i chose to get semi-spherical looking bumps.)

[gordon_heinrichsruscher]

Thanks for your answer.
But there are some misunderstandings I guess.. I will upload my max 2022 file with the setup.

Look at the Hightlights position as they move around when switching to VrayDisplaceMod.

[^Lele^]

Yeap.
It looks to me like the maps expect an sRGB transform, but they aren't given one (i.e. set to none/raw).
The highlights ought to go back where they were, then.
Also, ofc, you may just save the maps so that they accept a raw/linear transform, but that's best done from the source app.

[gordon_heinrichsruscher]

ok I will explain it differently.
create a general gradient ramp in the mapeditor and plug it into the displacement channel in your vraymtl
this will now render perfectly

now take this exakt map and run it through a vraycolor to bump and also plug it into the bumpchannel in your material
now your normals will shift as its doubled through the displace + the bump channel

----

this is like using a substance sbsar file. where it connects everything automatically
how do you use a heightmap and a normal map if both have the same information in the texture

[^Lele^]

how do you use a heightmap and a normal map if both have the same information in the texture

If the info in the textures is doubled up, the render Engine has to do the work as instructed: twice.
The info ought to be split properly at the source, i doubt anything else can be achieved after the fact (without splitting the data via compositing, in max or elsewhere).