Hi there 
Actually ,when import an obj poly mesh ,I just ctrl+shift and click on to the desired object to hide the other parts… or unhide …
Very useful
OOOPS! The 2nd solution suggested by Stonecutter doesn’t work with my 3DS MAX. 
Any Max user who know a way out? Thank you!
I tried the following ways in 3DSMAX, but none of them seemed to work after exporting and importing as obj format:
- assigning different Material IDs
- assigning different Smooth Group IDs
- naming a bunch of selected polygons
- detaching selected polygons as elements
(The last one was peculiar. When body parts are separate, the imported object could be divided into correct groups with the “Auto Groups” function. But the problem was that there’re seams causing problems on subdivision. When MRG was checked in the import panel, however, “Auto Groups” would fail to work again. 
Headache. Anyway out?
Hi,
I don’t know of any solution to this, I’m not sure if it’s the obj format itself or the implementation, but it doesn’t support material IDs or named selection sets.
If you export and import straight back into Max, you will see that they got lost.
Since other implementations seem to take the named polys as groups it would seem to be the exporter itself.
Cheers
You can assign your own grouping in ZBrush by hiding everything else and then pressing Tool>Polygroups>Group Visible.
This process is detailed in the ZBrush Quick Start by Martin Krol, found in the Practical Guide.
As you know, sometimes it’s more convenient to assign groups in 3D package, 3dsmax for instance, if possible. I’m sorry to know that there might be no way out.
Still, thank you all the same for your suggestions.
I’ve been working on and off on the same problem. Unfortunately there simply doesn’t seem to be a solution. Either the Max2Obj isn’t saving the file right, or Zbrush isn’t reading the OBJ file right. I completely agree that there are times when you simply don’t want to assign your groups in Zbrush, like when a mesh is too complex.
Hi Zeddicus,
ZBrush will export and import whatever groups are currently assigned to the model. When you export to or import and OBJ from another application, make sure that you have used the proper settings so that group assignments are not discarded. Unfortunately, I cannot help you with what those settings might be for your other software; I can only say that ZBrush is not discarding the groups.
<BLOCKQUOTE>quote:</font><HR>I’m not sure if it’s the obj format itself or the implementation, but it doesn’t support material IDs or named selection sets.<HR></BLOCKQUOTE>
For what it’s worth, I’m using 3DS Max 6 with the Habware plug-ins. The material ID’s are still saved in the OBJ file. I know because I just tested it out right now to confirm (exported, closed Max, opened Max, imported). The names of the ID’s vanish though. But if you highlight a poly and use the material editor to “pick from object” it will pull the material off of what ever ID is selected and put it into the material editor with it’s original material name and settings. So there you go, it shows that the material ID’s and the name of each material plus it’s settings (one blue and one pink Standard Max materials in this case) are being saved with the OBJ file, just not the material ID names. Hope that all made sense.
Hi,
I was being a little impatient with it - I’d assigned multiple IDs in the mesh, but not a multi-sub material in Max. If you do that it loses all the IDs at face level.
Face selection sets definitely don’t seem to work though, compared to Maya’s obj export.
No word from Habware about this, so I’m going to get a coder at work to have a look at the SDK (Someone said the source for the exporter ships with Max) to see if its fairly easy to implement.
Cheers
Well, I installed the SDK and can’t find it - it’s possible that the source to the Habware importer only ships with Max 6 (I’m still on R5), and I’m waiting to see how the restructuring has affected discreet with the next version…
Zeddicus do you have the SDK installed? Might be worth having a look…
Cheers
Hi 
If an external application does not export/import poly-groups, you may want to try the following procedure…
- In the external application, apply UV mapping to the mesh and assign different UV tile to each group. example: In a character mesh, the Head will be assigned the uv range of 0,0 to 1,1, upper body 1,0 to 2,1 and so on.
- Export the mesh from the external program (OBJ format) and import into ZBrush.
- Press the Tool
Polygroups Uv Groups. This function will automatically assign grouping based on the UV-tiles assignment.
Polygroups Hope this help,
-Pixolator
Hi Pixolator,
yep, I’m doing that at the moment with the multi-displacement plugin, which works well with Vray in Max.
It’s a shame that Max’s obj exporter doesn’t support the selection groups as it’s more convenient to do that than break up the UVs into groups, but that’s not Zbrush’s fault but a limitation of the HabWare exporter.
Cheers
<BLOCKQUOTE>quote:</font><HR>it’s more convenient to do that than break up the UVs into groups<HR></BLOCKQUOTE>
In Max 6 the Unwrap UVW modifier allows you to choose UV’s by material ID so it’s not too bad of a solution (yes, UV Groups work with this method that Pixolator posted). Still, named sets would be more conveniant as you say. Don’t have the SDK installed, but I could take a look I guess.
Edit: By the way I get some odd things going on with testing my 6 face cube. If I use the Unwrap UVW modifier in Max to put each face in it’s own UV range like this: 0,0/1,1/2,2/3,3/4,4/5,5/6,6 then each face will become it’s own separate polygroup in ZB. But if I set it up like this: 0,0/1,0/2,0/3,0/4,0/5,0/6,0 I end up with two polygroups, three consecutive faces in each. Not sure why this happens, but I’m guessing I’m just misuderstanding something about UV’s here.
<BLOCKQUOTE>quote:</font><HR>Someone said the source for the exporter ships with Max<HR></BLOCKQUOTE>
Just finished taking a look. If it is there I certainly don’t see it.
Edit: Found this written in the Max2Obj help file…
<BLOCKQUOTE>quote:</font><HR>Source Code
Some of the source code to build my free plugins is given away free from the author to anyone who wants to use it. There’s no Copyright, no Copyleft or something like that, take it as it is. If the source code uses material copyrighted by others, their rules must be applied. If I’m not allowed or I don’t want to give it away, you won’t get it.<HR></BLOCKQUOTE>
Hi,
I’ll drop him a line again see if I can get hold of the source for it. The only thing is if I do get the coders to edit it, it will only be for 4/5 rather than 6, so it won’t help those users unless they can find someone to recompile it for 6.
Not sure why you were having problems with the UVs - maybe there’s some overlaps there?
I was using 0,0 to 1,1 1.1,0 to 2,1 etc. and that worked OK.
Cheers
I’m sorry but the trick doesn’t seem to work for me. I’m sure I’m doing it correctly because when a texture is applied to the imported mesh, the texture was wrapped correctly due to different UV settings in different areas. But when I click the UV Groups Button, the whole mesh would be assigned to a single group. Wonderring why.
Can you post an image showing the UV’s. The Unwrap UVW modifier should work good for this. Or you could post the Max and/or OBJ file for us to look at.
Hey, it’s working now! I know what caused the problem. Thank you all. 
The first thing, I thought myself clever and assumed when the UV mapping is not continuous, it would be divided into different groups. But it’s wrong, Only when the polygons occupy different UV ranges would them be regarded as separate groups.
The second thing, make sure that one potential polygon group doesn’t extend into other UV ranges. Avoid even touching the borderline. Otherwise, there might be problems.
Well, here is the way I find most reliable and predictable. After the model is shaped, add an Unwrap UVW Modifier atop, and hit the edit button. Then first scale the whole mesh to make sure that they only occpy the range from 0,0 to 1,1 (You may use Pack UVs to help you.) And then, use all the techniques to select the bunch of polygons which are going to be in the same group and drag them into different UV areas as shown below. (You may need to use Detach Edge Verts when necesary) OK, now export. Bingo, you get it!
Can you post the imagen…? i can see it–
Thanks!