Create a NormalMap from the Bump on a VRayMtl?

[Morne]

Hi guys

Amazingly enough, I've never made my own normal maps. I need to get some normal maps, derived from existing bump on a VRayMtl. How would I go about doing that? (considering the bumps can be made up of more than just a basic jpg. It can be composite map etc)

The normal maps will be used in realtime engines

[DanSHP]

VrayNormal in bump slot then in the NormalMap slot within VrayNormal, VrayBumpToNormal. You can throw whatever Max composites you have in there and it will work.

I use it all the time.

edit: ah may have misunderstood. You want to retrieve Normal maps from bump maps for use in an external engine?

[Ihno]

What are you trying to do? Do you want just the bump from max as normal map? Or do you want to project the mesh detail of a highpoly mesh including bump on a lowpoly mesh?

You can use the VrayBumpNormals element inside of the render to texture dialogue to render what ever bump you've got, to a normal map. It won't look exactly the same because the colorToBumpMap from vray performs some unbakable magic but it'll be pretty close.

For the second case you'd have to mix the BumpNormals map with the baked (from highpoly) Normal Map (I'd not bake that in max, use zbrush or xNormal).
There is no really proper way to Mix normal maps. The MixNormalMaps osl from Rens is the closest http://www.rensheeren.com/blog/mixnormalmaps-osl/.
You'd have to add a third bake process where you'd put both normal maps (from highpoly and BumpNormals) in the inputs of the osl and bake it for example via the selfillum channel.

[Morne]

I want to convert the bump map to a normal map, for use OUTSIDE max in a game engine as a normal map (the materials in Unity have a slot for normal maps, but not bump maps)

[Ihno]

Yea well then its the first case. Use a plane (1:1) if its not model specific. Then you'll get a square.
BTW: the normal map conversion inside of unity (create from grayscale checkbox) also does a pretty good job. In case you've got a bump map or want to use the diffuse or specular as bump.
On a side note: Unity expects to get the normal maps in sRGB space.

Ps: in case somebody wants to do the highpoly bake + bump thing: Unity offers two normal map inputs. So you don't have to mix outside of unity. But that'll need a little more performance.

[bartel]

If it's just some surface texture/noise, you can bake in 3ds Max, but it uses a different tangent space than Unity, so anything more complex than that should be handled in a baker capable of rendering to Mikkt space.

[Vizioen]

Does 3dsmax still not support Mikkt space?

[Ihno]

The question is if vray does.. vlado