Is there a way to load V4 into zbrush to make  a new modified obj file , and retain the body part groups ?

The latest version of Zbrush does this automatically. I don't know why anyone wouldn't have the latest version since the upgrades are free. (Of course, you can use uv mapper to pre-save the group information and re-apply it to the obj. after finishing in Zbrush if you're experiencing some inexplicable failure.)

Markschum,
Go to your import/export preferences and you can select to either import by polygroup or by material.

I was working with Mark on this, and he forgot to mention that we're trying to retain the body part groups AFTER subdividing the mesh. I've been able to successfully mask a portion of V4s hip/legs to create an area where I subdivided quite a bit to give more polys in her genital region. The issue at first was, as soon as the mesh was subdivided in any section (in other words, not subdividing the entire V4), the polygroups were lost. However, I figured out that this could be fixed as simply as clicking the 'autogroup' button in Zbrush.

Marks' theory was that, if the general .obj doesn't change shape drastically, it should be feasible that a simple modification of the external geometry call in the .cr2 could call this new geometry with the subdivided mesh, and still retain V4s rigging, magnets, JCMs, etc. It's a good theory, anyway. Haven't gotten it to work yet.

The issue has been that all polygroups are not retaining their name. Mark wrote a quick Python script that reads all the polygroup info from an .obj. The polygroups are being renamed to numbers. Below are two sample lines that are exported from Mark's script, denoting a polygroup within the geometry. The first line is the .obj before sculpting and subdividing, and the second is after:

ef31ef31 -   1152 facets -   1279 vertices - group Figure_1 hip

82d8993b -  16451 facets -  16806 vertices - group Group8815

If there is a way to parse the correct group names into the new, altered .obj file, I think this could work. As it stands right now, once you edit the .cr2 to call the new geometry and try to load it in Poser, it loads... nothingness. Poser sees a model there, and the model has it's materials intact and everything, but the canvas displays nothing. It's as if it's loading the model data from the .cr2 but not it's actual geometry. Very strange.

Anyway, I think Paloth may be on to something by using UVMapper to keep all the group names and then reapply them to the .obj. I have no clue how to parse this information into an .obj at all though. Thoughts?

And DarkEdge, thanks for the email reply to my PM over at the Pixologic Zbrush forums and here. I tried that method, but the problem with reimporting that geometry into Poser in pieces is that the pieces are off ever-so-slightly from the model, even when zeroed, and I don't see how it will be possible to rig the pieces together and not have to worry about the seam breaks.

Any input on the best way to get the group names back into the .obj? If anyone wants to see .txt files of the exported group info from Mark's script, I can show you both before and after the sculpt in Zbrush. Thanks in advance!

Well, I can explain how to use UVMapper for this but I don't know that it's going to work in your case - nor do I think any morphs will either if you're altering the geometry (subdividing alters the vertex count). It has been awhile though.

For the UVMapper trick, you usually want to save a copy of the original obj you're working from, that way you have access to the previous grouping.  A simple copy and paste to a new location would suffice but you could also load the obj into Uvmapper and save to a different name. Then you do what you need to do in ZBrush and if it destroys the group names, you simply import the untouched obj's UV's. It will automatically reassign the grouping/materials as long as no changes were made to the vertex count. The idea is, since the geometry is the same order/number of verts, copying between a morph and the original won't cause problems.

Subdividing introduces new polys into the model though and that changes the vertex count, so if you save a subdivided copy of the model, you're gonna have a hard time. You'll likely have to manually rename the groups and probably kiss the pre-existing morphs good bye.

Quote - Well, I can explain how to use UVMapper for this but I don't know that it's going to work in your case - nor do I think any morphs will either if you're altering the geometry (subdividing alters the vertex count). It has been awhile though.

For the UVMapper trick, you usually want to save a copy of the original obj you're working from, that way you have access to the previous grouping.  A simple copy and paste to a new location would suffice but you could also load the obj into Uvmapper and save to a different name. Then you do what you need to do in ZBrush and if it destroys the group names, you simply import the untouched obj's UV's. It will automatically reassign the grouping/materials as long as no changes were made to the vertex count. The idea is, since the geometry is the same order/number of verts, copying between a morph and the original won't cause problems.

Subdividing introduces new polys into the model though and that changes the vertex count, so if you save a subdivided copy of the model, you're gonna have a hard time. You'll likely have to manually rename the groups and probably kiss the pre-existing morphs good bye.

This is very true and why you can't really fully sculpt a basic Daz mesh from the ground up. Changing the poly count is going to cause all sorts of issues like mentioned above. It would be very nice to do a truly high-end V4 sculpt but you can only work on the mesh in basic ways such as how vendors here do it for their custom figures they sell.

Getting everything to work would not be possible, at least without a LOT of work. The time would be better spent simply sculpting your own mesh in ZBrush and importing into Poser, Max, Maya, etc.

Quote - Subdividing introduces new polys into the model though and that changes the vertex count, so if you save a subdivided copy of the model, you're gonna have a hard time. You'll likely have to manually rename the groups and probably kiss the pre-existing morphs good bye.

Right, that is known which is why the subdivision was done on an already morphed V4.2 character, so that all morphs I wanted were already present. I'm not trying to create a scalable model here, capable of being morphed and remorphed using existing Daz3D morphs. I am just trying to introduce more polys to her hip/thigh region, allowing this area to be better sculpted anatomically. I understand and am proficient in morph targets, so I can create my own without relying on the Daz3D ones. Basically, I just want this .obj to be referenced by a copy of the V4.2 .cr2 so I can use V4s rigging and magnet information that is contained in the .cr2 on this new .obj. Making morph targets since Zbrush 3.5 has been insanely easy, since all UV mapping and material zones can be kept intact. I can create my own, but just want a higher res geometry with which to sculpt. But subdividing the whole mesh is not necessary and just insane, since the polycount would choke Zbrush and Poser both.

I have UVmapper Pro so I'll see if I can give your method a shot.

Quote - Well, I can explain how to use UVMapper for this but I don't know that it's going to work in your case - nor do I think any morphs will either if you're altering the geometry (subdividing alters the vertex count). It has been awhile though.

Not trying to muddy the waters as they say nor am I trying to contradict Teyon, but with ZB4 I'm not sure if the above is true anymore (??).
I just created a figure last couple of weeks and have created morphs in higher sub-divisions, brought the model down to the lowest sub-d and have imported those morphs into Poser with no problems at all. Not sure why it's working for me.

That's not quite what I meant. You exported the lower res model. I meant exporting the higher res, which is what SmashStudios3D was talking about.
 
You're right that going up doesn't matter as long as you go back down for export. I do that all the time at work. :)

Why not just export the high res displacement, I wonder...?