Vector Displacement from mudbox2011

[griml0ck]

Hello,

One of our very talented artists here at Swiss managed to get Vray to render vector displacement maps from mudbox. Here is what you do in 10 easy steps:

1. Extract an Absolute Tangent map from mudbox.
2. Import mesh and assign a shader with a displacement file texture.
3. Between the file and the displacement node you need three nodes:
Multiply
+/- average
blendColors
4. Connect from the file texture (use the "Other..." option):
OutputR -> Input1.X
OutputG -> Input1.Z
OutputB -> Input1.Y
and set multiply input2 values to 0.5 0.5 1
5. Connect multipyl to +/- average input [0].
In the Average node create a new item (under input 3D) and set it’s values to 0.5 0.5 0
6. Connect output from average to blendcolors color1. Set blend to 1.
If you don’t do this step Vray will crash.
7. Connect blendColors to the displacment node
OutputR -> displacement
8. Create a Vray displacement control node for your mesh and set it to Vector Displacement
9. I usually smooth my mesh 2 times before rendering.
10. In renderGlobals under Vray/Misc check the "allow negative shader colors", now render!

/ Johan

[vlado]

Very cool; but you should be able to do the same just with the Color Gain and Color Offset parameters of the File texture, no?

Best regards,
Vlado

[griml0ck]

First your switching the green and the blue channel. Then the operations channel specific. So I think that is hard to do with the file texture I guess you could basicly let Vray do this under the hood, so people wouldn't need to convert the textures in this way. Would be nice with a dropdown menu so you can select which kind of vector map you feeding into Vray.

You can also do these operations in a comp program and then you wount need to do anything special in maya. It's the same procedure in comp:
1. Switch blue and green channel.
2. Multiply red and green channel by 0.5
3. Add 0.5 to red and green channel

This solution is only for the "Absolute Tangent" from mudbox. You also have "Relative Tangent, "World space" and "Local space" vector maps. Should be possible to convert them as well.

Best regards,
Johan

[vlado]

Ah yes, I missed the switch of the red and green channels. Yeah, we'll probably need some way to switch the different vector map types. I'm curious how this works with PTex textures where you don't have a mapping channel to use as a reference frame...

Best regards,
Vlado

[Reaversword]

Yes, I'm agree with griml0ck, this "substeps" shouldn't steal at Vray for Maya users the time needed to research the way. We want do the map and apply it. Maybe Chaosgroup should prepare some presets for displacement vector (perhaps mudbox, xnormal, modo...). In the same way, talking about displacement, would be cool to have a parameter for define the "zero point", if is black (0), or grey (0.5), in place of use the expression displacement offset = displacement amount * -0.5.
From my point of view, besides Chaosgroup works on an incredible rendering engine able to fake the light in a impressive way, the Vray product is aimed for a final user, not like Mental Ray, that is aimed for a company for embed it in its softwares, or renderman, aimed for programmers. So, like user, we want create the maps and getting it work as fast as I can hope, without uncomfortable configurations and settings.

[gardeler]

@Johan
Thank you for sharing this. Very useful!

/ Marre

[vance3d]

preprocessing the mudbox vector displacement map in nuke as described above works for max vector displacement too.

V Miller

[Zach Gray]

Hello,

One of our very talented artists here at Swiss managed to get Vray to render vector displacement maps from mudbox. Here is what you do in 10 easy steps:



/ Johan

This doesn't work with pTex just yet. Still struggling with this one. I haven't been able to figure out the proper channel assignment yet.

[Reaversword]

Some news about Vector Displacements Maps in Vray 2.0?

Appears now in Maya we have in the displacement node the new "vector displacement" field, a 3 channels conexion, in place of the classic of only one.

But still like in the past, I am unable to get working Vector Displacement in Vray.

I have no license of Mudbox, I'm Zbrush user, so like Z is not capable to create it, I still keep using Xnormal to do the work, but seeing the hard configuration of Vray and the heavy loaded options of xnormal for creating "bent normals maps" (Vector displacements), with settings like "number of rays", "bias", "spread angles", Distributions type "uniform, cosine or cosineSq"... Any hint to aproximate this settings to Mudbox's "absolute tangent mode"?

I could stay doing test among a week and only waste it.

Any clue to get it working?. Someone knows any solution beyond "sell Zbrush and buy Mudbox" (that gonna be no)?. Still remains being so complicated settings Vector displacements mappings now, in vray 2.0?

[Reaversword]

*Doubled posting* I'm sorry.

[vlado]

I'm not at all sure that "bent normals maps" is the same as vector displacement. Weren't they used for reflection occlusion? (It looks like it, from the options that you describe - they make more sense for reflection occlusion than for vector displacement.)

Using vector displacement in V-Ray is actually very easy as you can see from this tutorial: http://www.spot3d.com/vray/help/maya...splacement.htm

Best regards,
Vlado

[Reaversword]

Humm.. appears you're on right.

Any alternative to Mudbox?... or Modo?

[vlado]

V-Ray for 3ds Max can sort of generate vector displacement maps, as described here: http://www.spot3d.com/vray/help/200R...cement.htm#ex8

Nothing for Maya at this point though, I'm afraid.

Best regards,
Vlado

[Reaversword]

Buff, any lucky with nothing. The only way to get working Vectorial Displacement Mapping appears to be with Mudbox, like we know, but for me its not an option.

xNormal appears cut the 32 bit range or something like that. While I can see Mudbox smooth degrades, xNormals do it very contrasted...

I can obtain well displacement from Zbrush>Luminance, or Zbrush>Toxik (Maya Composite), but Vector Displacement, only from Mudbox... but not "Ptex" Vector Displacement... neither from Mudbox!.

I'll live in this Nightmare till I topple this width concrete wall or till break my head against it. I know I'm simply loosing precious time, but I need extract all the detail from my Zbrush work and get Vray rendering it!!!.


Vlado, respect this VrayVectorDisplBake of Max... Is in the To-Do queue for the Vray for Maya?, Any test? Any Nightly Build? ..and by the way, you have changed again the nightlies page, right?.

[t.petrov]

..and by the way, you have changed again the nightlies page, right?.

No, it is the same. Write an e-mail to the support if you have problems getting new versions ( vraymaya@chaosgroup.com)

/Teodor