Hi All,

I have been asked, how I use ZBrush for creating iClone models, so I will try to explain.
First of all can say that there is no big differences between creating models for iClone and for other 3D applications (DAZ studio, 3ds Max, Maya e.t.c.). If You already use ZBrush for these programs You will have no problems with iClone too, so this topic is not ZBrush tutorial, but just set of recommendations how to create iClone compatible models and textures in ZBrush.

1. UV Map.
ZBrush processed model's UV in specific way -- by default inside program model's UV flipped vertically. So first thing I recommended to do after importing models is arrange UV settings -- In UV map section set UV Map Size (I usually use 4K) and press "Flip V" button. After this You will be able create some work textures (masks, displacements... ) in external apply them on model correctly. All created ZBrush and exported maps (Normal, Displacement...) also will have correct UV layout.

2. Subdividing.
ZBrush has 2 important settings for model subdividing - "Smt" (Smooth Mesh) and "Suv" (Smooth UV). To avoid significant changes in UV layout I do not recommend to turn "Suv" ON; typical settings are:
Smt - ON;
Suv - OFF.

3. Crease.
If your model is not "solid" and has open edges (borders), You should "freeze" these borders before first subdividing to avoid deformations - press "Crease" button in Geometry section.

4. Cloth fitting.
When ZBrush subdivide the model, the model's volume slightly decreased, also You can push surface too much and intersect cloth with body. To avoid these problems, in addition to cloth model You working at You should have the body model in the scene for visual control (as reference).
To do this use Subtool > Append feature of ZBrush.

5. Normal map export.
For exporting Normal Bump Map for iClone I use these settings:
Tangent - ON;
Adaptive - ON (longer calculation, but better result);
SmoothUV - ON;
SNormals - ON;
Flip G - ON (REQUIRED for iClone compatibility! ).
Switching SmoothUV to ON slightly changed original UV, but helps to avoid artifacts in the map.

6. Displacement map export.
There is no support for Displacement n the current version of iClone and You are not able to apply this map directly, but this map can be useful for "shading" Diffuse and Specular maps in Photoshop.
Recommended settings for export are:
Adaptive - ON;
SmoothUV - ON;
DPSubPix ~= 2

7. Model export.
When You export finished low-level model from ZBrush, please keep in mind that although result mesh will have the same number and order of vertexes, the orientation of hidden edges can be changed and UV layout will be slightly different. So usually I do not use exported mesh directly, but use it as morphine target for original mesh before sculpting.
If You would like to use exporting model "as is", do not forgot to flip UV vertically before export (if You flipped it after import).

Of course each developer has his own "now how", so it's just description what tricks I'm using myself, but hope they will be useful as "start point" for those who just start to use ZBrush for iClone.
Good luck!

P.S. More Tricks :

8. Multy Sub Materials.
ZBrush can works with single UV space only and if You load model which have multysubmaterials, Zbrush "merged" UV layouts from each material into single UV space. As result You can have intersection between UV layouts from different materials.
The example of such model is G5 head. It has 2 materials applied -- Face (ID 1) and Cavity (inner mouth, ID 2).
So when Zbrush loads G5 head model it put both Face and Cavity UV layouts in the same UV space and You will not able to generate textures in ZBrush normally because layouts will be significantly intersected (although it's not important if You need just deform a mesh).
I can explain 2 methods to solve this problem:
The first one -
After loading into ZBrush You should "separate" model to polygroups (by polygon ID) and export materials for each polygroup separately.
The second one -
To modify model's UV layout before importing into Zbrush. You should "combine" all material's UV in single space without intersection in some 3D application (3ds Max or Blender for example).
You can and scale sub-materials UV groups, but do not rotate them (!) otherwise generated Normal Bump texture will be incorrect.
It's not difficult to make such operation, but You should keep in mind how You will "separate" textures exported from ZBrush to parts for single material and this can be tricky.
For G5 Head it's not big problem at all because textures for Cavity is not important. Just scale and move Cavity UV into some free place in main UV space occupied by Face material. After textures will be exported just ignore Cavity texture part or fill it by background color.

Vit

Thanks for such a detailed guideline. I am sure it's going to be an exciting thread when others pitch in. I may have several questions on the subject as I absorb the whole thing. But I am not able to resist few simple questions to begin with :

1) Do we need just ICLONE and 3DXchange to import an ICLONE compatible model from ZBRUSH or anything lese ?

2) Is it FBX format that we need to use to import the model or some other format ?

3) Will the model be compatible enough to use Clone cloth and ICLONE hair ? Because DAZ models can not use ICLONE clothes and hair.

May be the guidelines for these questions are there on the forum / site somewhere. But I am not aware.

A little guidance will help.

Thanks PrabhatM. I'm glad that my answer to your question is useful.
To your other questions...
First of all I should say that I use plug-in for 3ds Max, which export models directly in iClone format and all my characters are Standard (G5) characters. Currently plug-in for 3ds Max is only possible way to create Standard (G5) characters; 3DXchange does not allows to do this.

What do You mean when say "iClone compatible model"? Basically there are 2 types of models in iClone :
- static models (props) without bones;
- dynamic models (usually characters) with skeleton and rigging information.
To create prop You can use any format supported by 3DXchange. To create character You need format which includes bones and rigging information -- FBX.

You can find more detailed answers to your question in Developer Center.
There are a lot of development documentation and tutorials there.

Vit

Thanks for reply.

For a moment I had forgotten about the ICLONE Plug-in for 3DS MAX.

Do I presume the Pipeline as : ZBRUSH >> 3DSMAX ( ICLONE Plug-in for 3DS MAX ) >> ICLONE ?

Not exactly... My main tool is 3ds Max and I prefer to create raw model in this program and if I make something new my pipeline is longer and consists of 2 main steps:
1. Topology creating -- 3ds Max (raw model) > ZBrush (raw shape)> Topogun (topology) > 3ds Max (UV mapping);
2. Shape tuning and rigging -- 3ds Max (basic model and rigging)> Zbrush (final shape and Normal Map) > 3ds Max (final model and rigging)> export to iClone using plug-in.
On step 2 I also create final materials (Diffuse, Specular and Normal Bump textures) in Photoshop, then test them in iClone and tune if necessary.

Vit

Great. The effort shows in your work.
We will eagerly wait for your new work.

hello tutor,
thanx for your detailed description - i followed i think exactly. but my uv's completley messed up.
when i push the morph uv button it look like zbrush 4r6 upside down the existing uvs from iclone.
i really dont know what i am doing wrong...please help me out before i eat up my keyboard....

and after create texture map....

Hi rutazr4,

Frankly speaking, I do not understand - What was your aim when You pushed this button?
As I told in description, ZBrush processed UV in very specific way, so better do not use any UV operations except UV flipping. And my description expected that You already have final version of UV on your model before importing it into ZBrush.

Vit

Great thread Vit, I've been quietly reading hehe! Thank you!

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Thanx for your reply Vit3D,
the morph uv button is only to display the way zbrush unfold, I never touch the unwrap button in zbrush because for sure I wanna keep the original uv's from iclone. Even when I import to 3dsmax and GoZ it to zbrush the same strange behavior appears. Maybe its an version problem? What version of iclone and zbrush do you use? Is there a way to export explicit uv's from iclone? the silhouette from the texture map looks quiet the same as iclone but why zbrush twisted the head like an old sock.....