Zbrush - Zremesher not keeping Polygroups

synergy11

Good evening.

From the pixologic website it says Zremesher will keep the polygroups after it runs through it's operation. I've clicked Freeze Groups but nothing seems to work.

All polygroups are lost after running a zremesh operation.

Am I doing something wrong or is this something that is not possible?

Thanks!

cryrid

Its working for me.
Do you have screenshots that might help pinpoint your problem?

synergy11

I will post a screenshot as soon as I get home from work.

Thanks.

synergy11

Some Screenshots attached. Before and after.

cryrid

I was hoping for a full screenshot in order to determine the version number and if symmetry was turned on.

Otherwise there's some weird coloration going on with the mesh. I'm not sure if it is just jpg compression or a moire effect, but it gives the illusion that there might be multiple polygon islands / elements in the same place. Couldn't hurt to double check and make sure that it is a single solid volume.

Have you run any other tests to see if it will preserve polygroups on other meshes, such as the default sphere tool? This could determine if the problem is with your tool or your machine.

synergy11

I did have symmetry turned on. Although I'm pretty sure I tried it with both. I will check again when I get home.

The version number is the latest version of zbrush.

How do I check in zbrush if my object is a single solid volume?

Note: this model was created using dynamesh, which keeps polygroups on insert curve brushes which is what I used to build this model. I'm not sure if that helps?

I will run a test on a simple sphere asap.

Thanks.

cryrid

Definitely turn symmetry off for a start.
ZRemesher will use symmetry if its on, which could cause the polygroup on the side it uses to overwrite the one on the side it replaces (although the result you got didn't look all that symmetrical?).

synergy11

Alright. I Dynameshed a sphere then used an Insert Mesh Sphere brush to draw another sphere with a new polygroup. Then I Dyanamesshed both spheres togerther. I double checked the polygroups were still intact, then I ran a zremesher and it worked great.

Not sure why my Tree stump is not working!

cryrid

Are you able to upload it anywhere?

synergy11

It works now!

I must have fudged something up when I duplicated the sub tool. I went back to the original sub tool and ran the zremesher operation and it worked as expected.

This will make using UV master much easier by putting each trunk branch on it's own uv island by polygroup. Unwrapping the whole object was causing my bark texture to run horizontal in some parts. hah.

Thanks as always Cryid.

synergy11

Damn. I spoke too soon. When I ran zremehser again to reduce polygons further it once again gave me a new polygoup for the whole object. And the reduction of polygons was minimal even though I selected HALF .

Just to make sure. I have HALF and ADAPT on and FREEZEGROUPS turned on before I run zremesh.

synergy11

I'm not sure where I could upload the .ztl file? Email it?

cryrid

Sure.

Edit:
The tool seems to remesh fine on my Surface while properly preserving the polygroups, so the problem doesn't seem to be in the model. My only guess at this point in time is that you might have Tool:Export: Grp turned off (I think zbrush does some exporting when it goes through the process, unless that was just decimation master).
(Edit 2: Weird. This export option caused me to lose polygroups when I first tested it, but now it doesn't seem to make a difference and I maintain polygroups either way)

As for the other issue: It does take a long time to calculate and the results are still pretty highpoly; this is due to it trying to preserve the exact polygroup borders exactly, and they are pretty dense.

If you really wanted to shrink it down, you could try this work flow:

1. Duplicate the tool
2. Remesh it at the polygon count you want. Don't preserve any groups (though you could possibly try polishing them a bit and converting them to curves)
3. On the other tool, fill each polygroup in with a distinct color
4. Use Project All to transfer the polypaint to the remeshed tool
5. Create new polygroups based on the polygrousp
6. Maybe do a group loops pass with 1 loop, to get a nice flow.
7. Select a group, grow visible once, and create a new polygroup (group visible). Repeat this step for the other 3-4 groups.