Issue with Exported File and File Size ? - 3DCoat / DAZ / ZBrush

[Laticis]

Hi,

Seeking some advice please and any insight regarding an issue I am dealing with.

Software being used:
3DCoat 2023.27 / DAZ Studio 4.21 / ZBrush 2022.0.7 / Windows 10

Issue:
Exported file size from 3DCoat larger than expected and the exported file disables my ability to create morphs or updates using the original base mesh.

Process:
I have created a cluster of rocks, with a decimated triangulated mesh in ZBrush and created a UV Map at 4096 x 4096 - File Size after export = 5,328 KB
The UV Map created in ZBrush was full of under-utilized space, so I brought it into 3DCoat to utilize the UV packing features.
Imported settings attached and the result of repacking the UV's in 3DCoat.
New UV Map applied and the mesh exported - File Size after export = 8,649 KB
New mesh Imported into DAZ Studio.
New mesh would not accept changes made in Zbrush to the original mesh via GoZ

Problem:
The first noticeable difference is the file size exported from 3D Coat is quite larger compared to the original from ZBrush.

I started looking at this because when I re-imported the new mesh from 3DCoat and I wanted to create an adjustment morph for the rocks.
For this I generally work with ZBrush and GOZ and create the morph or adjust the placement of the rocks.
Unfortunately, I could not do that with the newly imported mesh and the original file.
It not a big issue, because I can just port the new mesh.

But I wanted to know why. Its generally because the vertices count changes which is what my initial assessment was.

After comparing the original file and exported file from 3DCoat, in Zbrush I get the following results: same poly count: 77,538

BUT the Active Point count was different:
Zbrush Original mesh: 39,239
Exported 3D Coat  mesh: 77,607

So, ran Mesh Integrity & Fix Mesh in ZBrush and this certainly worked, repairing the imported 3DCoat mesh rverting the mesh back to 39,239 active points while maintaining the new UV's created.

Not only that, during the process the repaired 3DCoat mesh with UV's 4096 x 4096 has a new file size: after export = 4,806 KB

But even now, with the matching polys and points match, I can't create a morph or mesh change from the original mesh to the new.

Questions:
Why does there seem to be extra vertices created by 3DCoat upon export of the mesh?
Why if the mesh is now match after repair it wont recognise chnage to the original mesh?
Am I doing something wrong?

All I wanted to do was to update the UV's but boy, did that lead me down a rabbit hole

Any input, feedback or advice is greatly appreciated.
 

[Laticis]

Small update.

When importing file for UV Mapping, if I select Triangulate, the exporting mesh matches the existing.

But there is still a files size variation. Zbrush = 5,188 KB / 3DCoat = 7,445 KB

[Carlosan]

Try locking normals at import

[Laticis]

Hi Carlosan,

Thanks heaps mate...that did the job nicely, worked a treat. 
File size still higher but it works.

Is there a simple explanation why?

Sorry, I only associated normals to textures, guess I need to do some homework

[Carlosan]

At import stage if that set is turning off -without locking your normals- 3DC will recompute them (this set is important also when using an imported normal map on paint room).

As the tip said, with this option ON 3DC dont recalculate normals, use normals directly from the object file.

[Laticis]

Thank you very much for the information and the help Carlosan

I will do a little more research on the topic of Normals.

[Laticis]

Hi,

I have run into the same issue again with a model exported from Zbrush - UV'd in 3D Coat

3D Coat upon adding extra vertices. 

I tried what was suggested last time locking normals, ran auto UV on the mesh and exported that and get the same error message.

I never use to have this problem. There used to be a fuction  to export the mesh from the UV room but that is no longer there.

Any thoughts on what I am doing wrong?

I checked the export mesh from Zbrush and that is fine.
Importing any mesh tests, exported from 3D Coat is giving me an "The imported mesh contains unused vertices."

[Carlosan]

Are you trying to export as obj or fbx ? same result ?

[Laticis]

Hi Carlosan,

Only as an OBJ file at the moment.

I am running some test trying to find the issue.

Last test, just imported the mesh as 'Retopo Mesh' into the Retopo Room, then simply exported that out as a 'Poly Object'

That imports into Zbrush without the error message, but DAZ Studio wont recognize the new mesh so I loose any morph creating abilities.

-------------------------------------

I wouldn't be panicking so much but I have already rigged the character and all I want to do is give it UV maps.

I just tried transferring the rig/weight map to the new mesh with UV's but it messes up the mouth.

[Laticis]

Just to add some additional information.

The reason I took it back into Zbrush and exported from Zbrush was to create some polygroups for separation, mainly for the inner mouth.

[Carlosan]

I can think any solution sorry, this issue it is not very clear.

may be some edge tris was added to the original ?

[Laticis]

Here's a simple little test that creates the same problem for me.

Step 1 - created a simple beveled cylinder with polygroups.
Step 2 - exported mesh as OBJ
Step 3 - imported into 3DCoat with Lock Normals on
Step 4 - auto UV Mapped
Step 5 - file/export
Step 6 - Import into ZBrush ( error message pops up showing contains used vertices )


 

[Laticis]

I just reset 3DCoat to Default settings....tried again with this cylinder not worrying about Lock Normals and got the exact same result. Extra vertices.

So I then tried a simple quad sphere...one without Polygroups and one with...and that had no issues at all, vertices count remains correct.

I feel this is a bug somehow, not my workflow.

[Laticis]

I feel safe to say and confirm this is a bug with 3DCoat

I just installed 3d-Coat-V4_1-17D-64, in this version with the very same cylinder as above....no issues ( other than I dont have access to my NAS )

And from the older version, I was able to go to the textures tab at the top and Export the UV Obj from there.

[Laticis]

Hi

Just to touch base on this issue again.

Is there anyway to avoid the additional (and unused) vertices that 3D Coat 2023 is adding to meshes after importing mesh for UV mapping and then mesh export?

It's currently affection my workflow for creating DAZ products and morphs in ZBrush. I thought I had found a workaround but it's not bullet proof and still failing on simple meshes.

From what I have found after some Google searching, there seems to be scattered instances of this happening.

Cheers Ady
 

[Carlosan]

in the Preferences > Export pallet there is a button labeled Grp if pressed it will export poly groups a separate objects (adding more vertex), try turning it OFF

[Laticis]

Hi Carlson,

Sorry for the delayed response, I have been on leave. 

Happy New Year and all the best for 2024

I will try that as an exercise, but that export feature in ZBrush is extremely handed when it comes to setting up a mesh for rigging ( or surface regions ) in DAZ Studio.
Making these regions in ZBrush is much faster and more efficient than DAZStudio.

I am slowly chipping away at a workflow that works for me.