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Imported Mesh Exploding.THE FIXX.

ZBrush Usage Questions
#71

Hi!

i had the same problem over and over again. Messed up meshes in the higher subdivs after reimport a lowpoly version with new uvw coordinates.

i think i got the solution:

i presume you export the lowpoly version out of zbrush into your favourit 3d app (in my case: 3dsmax) and then fix your uvws - export it back as obj and reimport into zbrush into the highpoly version.

the fractal mesh problems in zbrush are the result of small changes in the topology that happens during the exchange between zbrush - 3d app - zbrush.

Solution for 3dsmax (should be similiar in other 3d apps):

-reset max

Import
during the obj import dialog in max you have to choose the following settings:

  • Single
    checked - rotate model
    checked - Texture coordinates
    checked - Normals
    UNCHECKED - unify <— ! this causes the problems! it modifies your topology!
    checked - Obj smooth groups
    Vertex scale 1,0
    unchecked - Center Pivot

the “use materials” doesnt matter

UVW fixing / Creation
-now convert the model into “editable poly”
-use the unwrap UVW modifier to fix your uvws or create new one

!dont change ANYthing in the topology of your model!

Export
then you can “export selected” your model with following setting:

group by: object
(materials are ignored)
checked - rotate model
Faces: Polygons
checked - Texture coordinates
checked - Normals
checked - Smooth groups
Vertex scale 1,0

of Digits: 6

UNCHECKED - Compress numbers <-- this would change
UNCHECKED - Relative vertex numbers <-- your topology! ->BAD!

Back in ZBrush

-load your zbrushed model with all the details.
-go to subdivision step 1
-import the lowpoly obj with the new UVWs.
-you can then go to the higher subdivs again. and everything should be fine.

If you make the smallest change in your model. during import or export, it wont work!! just try every combination in the import and export settings and make sure your obj is just changing the uvw coordinates!

this worked for me…

Greetz

PS: i have another problem with multiple UV Sets and the ZMapper. if i try to create a normal map for one UV Group, the zmapper just creates randompixels and displays a messed up mesh. Any suggestions? except the method with groupSplitt. i dont want to use subtools.

#72

The funny thing is that this happens if you try to upres after you import, not when you downres the mesh.( I realized this after needing to fix one of the mid res version in my modelling app)

Pixhellman, changing topology has nothing to do with it. I have cases where I took my zbrush model to modelling app and making drastic proportional changes and bringing back without having any problem. This is a kind of problem does show up when you need a real fix or real uv for your model, and it does not show up when you try to explode a mesh for fun.

One other issue is pixel pixol ratio sometimes is not that great thus you cannot zoom to your model enough, so you need to take the model to another application. And most of the time zbrush explodes these meshes. I had cases where simple uving explodes the mesh inside Zbrush.

I think that this is somehting introduced during 3.1 update. AND THIS NEEDS TO BE FIXED ASAP.

Btw if you have found a fix or work around , please do not share or post here. Because as long as there is a so called work around Pixologic wont solve the real problem.

#73

Here is a dramatic case,

I am working on a creature head at the moment and I have needed some fixes outside ZBrush. I exported the model from ZBrush, imported in to Modo. And I did some test changes and test uving to see if ZBrush would explode this mesh before I spend my real time for real work in Modo. I exported from Modo, it is all good Zbrush imports fine, no explosions and I was happy. Great story is not it?

Well since Zbrush was not exploding the mesh I thought I should work on the fix and uving. I imported the very same model into Modo. I did proportional fixes and some other changes that was similar to ones in the test. I exported the model when I was done. Well you think that it should not explode right? It actually exploded and wasted just my 2 hours. Is not it great story?

#74

The FBX solution doesnt work for me and I’m not going to be able to import high rez models into max …
When are we going to have a decent workflow between Max and Zbrush ? :frowning:

#75

" If you do these steps the mesh will not explode because you are using a virgin model directly from the application. note:"

Actually I do not agree with this particular finding. Virginification of high or low model has nothing to do with this. You wont get explosion not because you have a virgin mary model, but because most likely from high res to low res(downresing) wont explode any model. Explosion most likely happens during up resing your model. So in your case since you cannot go higher than the highest resolution you wont get explosion. You were just lucky to find out that this method works, but your final finding is not quite the only explanation to this issue.

Try actually exporting 3 versions from zbrush, lowest, medium and the highest(a model that gives you explosion headache) .Then import into Max and export them out of Max and do the same method you just explained. But this time once you have established your subd levels goto medium res and import your medium max exported version. Most likely you will get exploding polygons.

#76

I tried the “virgin model” technique.

I open an OBJ with properly unwrapped uv’s . . . when I import the highres (finished sculpt) model over my subdivided unwrapped model it will not explode into a porcupine mess . . . .

however it still has the crummy old uv’s that are no good to me.
I even applied a texture . . . that worked on the properly unwrapped piece and dissapeared when I threw the highres mesh over it.

Am I missing a step?

Is it stupid to try and uv a piece after you sculpt it?
Is everyone else just unwrapping before they put all their detail into the meshes?

#77

I have the same problem except I’m not even importing into a 3rd party application. I simply export my low res, export my high res then:

Import low res to new
Sub Div low res to same as high res
Import high res

When I adjust to the lower sub div levels it looks fine and then as I go back up it explodes.

Again, this is when I’m simply exporting directly from ZBrush and importing straight back into ZBrush.

#78

Kosher

Thank you for confirming my points!! They need to fix this …crap.

All these solutions in Zbrush forums regarding this problem are all accidental . None of them are real solution. Zbrush has mental problems when it comes to importing into existing geometry. It can not even handle its own geometry-image formats properly(I had very same issue you have in the past as well) . This is very much overlooked issue and I would say that ignorance plays some part in this particular problem. People are b…thing about this for quite sometime and I have not seen anyone from Pixologic to comment on this problem. Only god knows why they have choosen to do so.

#79

I’ve noticed something that might be related. In the original mesh, I hide a certain polygroup and then as I slide down to subdiv level one, part of the polygroup becomes unhidden.

Could this be some indication that the UVs from the very lowest level are different than the levels above it? I have also tried just exporting from subdiv level 2, where the issue mentioned above does not occur but I still have the exploding mesh dilemma…

Yes, this is no fun.

Could it also have something to do with the detail painted in layers at the higher sub div level?

#80

Ah ha! Got it! It had something to do with the fact hat I was hiding polygroups and exporting.

I was unable to use the delete hidden button until marcus responded to my recent post about being unable to get rid of the HD layers, where he says to use the SubTool Master. I duplicated my tool using subtool master and the HD layers vanished.

I then opened up the new ZTool I created from the SubTool Master, went down to my lowest subd level, hid the polygroups that I didn’t want exported, then used the Geometry>Delete Hidden function (this was the key). Before I was just exporting without deleting hidden.

Now all is well and I was even able to keep my high details that were in layers.

Good luck!

#81

I just wanted to post today`s Zbrush art.

[greenshot_2008-04-06_13-19-44.jpg]

#82

Yeah, mine ended up breaking again too. Exploding mesh is back even though I thought I resolved it about two posts ago. It’s weird that I was able to get it working with some magic combo but now it’s not.

Sorry to see so many people having trouble.

I am trying out Silo now, which has a topology brush. www.nevercenter.com

UPDATE

Silo won’t even run on my Vista x64 machine. Trying on my Mac now.

#83

Kosher I told you, you are wasting your time to find an ultimate solution to this. Trust me I wasted tens of hours on this, there is no light at the end of the tunnel. Best thing you can do is keep complaining about it until they fix it which is the path I have taken at the moment.

#84

Hey I use maya and I was having a very similar problem. The whole reason that massive explosions like those occur is because the vertex order changes. So one fix I found is that when you import your model into maya make sure to uncheck “Create multiple objects” all the way on the bottom of the import options.

#85

Hey everybody! I think I have aged a year in the last 24 hours, but thanks to this forum and some keen suggestions by garycrump and Boa, it worked! :lol:

I was getting exploding meshes and tried all kinds of options to no avail. This is what worked for me, using ZB 3.1 and max 9, SP2:

If you are using 3ds max 9, get SP2. It’s free and easy to download. I think there is something wrong with the obj exporter in max 9.


  • Export sDiv 1 from ZBrush as an obj.
  • Import in to max 9 and tweak UVs.
  • Be sure to use Edit Poly to ensure face count is the same. (I noticed several people could not import their obj files in to ZB due to a different face count. Edit poly should resolve that. Right click to get Object Properties in max and check vert and face count - compare that to sDiv 1 in ZBrush).
  • Export tweaked model from max as .fbx with options as Boa suggested.
  • Convert .fbx to obj with both Force Tri and Compute Link unchecked.
  • At sDiv 1 in ZBrush, import the new obj file.
Thank you everybody!! The dark clouds above me are clearing away now.
~Scott

www.martinarts.com

#86

amazingly simple and effective workaround thank you so much. :+1:

#87

Another masterpiece from Zbrush today.

[greenshot_2008-07-10_12-37-33.jpg](javascript:zb_insimg(‘99246’,‘greenshot_2008-07-10_12-37-33.jpg’,1,0))

#88

I think u guys who can’t fix your problems should post those tools and ask nicely if anyone will have a look?
Sounds like you may have merge vertix uv’s on, wither in import or export?

#89

hi everyone, been having this exploding obj thing for while and the only thing I found to work is converting the mesh to a editable poly, here’s my work flow

  1. model in zbrush,
  2. export to obj all standard settings
  3. import to max 9 sp2
  4. repose/edit uvs, or what ever you want to do, except not changing the vertex count
  5. convert to editable poly (i found converting to poly before or after makes no difference.)
  6. export back to obj
  7. import to the same subdivision you exported at then move up to the highest subdivision and every thing is updated correctly.

This seems to work for me, I hope this helps someone as its a very frustrating problem.

#90

Weird. I used to have this problem with almost every model. Now I can’t get the same spiky result even if I tried… This is so random…

Make sure that on import to max you have “normal” checked and “unified” unchecked.