[Solved] Imported obj versus tweaked exported obj - different vertex count ?

[Renpatsu]

Hello,

 

Very new to 3D-Coat and hopefully I am posting in the right place

 

At the moment I am trying to add morphs to a model, which requires that certain model parameters like vertex count, vertex order, and face count stay intact.

 

Currently I am using the following steps, which as of now fail:

1) Import a Wavefront object into 3D-Coat as “Reference Mesh”. The object consists of three material groups, though I tried different grouping approaches
2) Switch to “Tweak” room and tweak around, e.g. smoothing
3) “Export Model” from 3D-Coat as Wavefront object with default settings as low resolution mesh
4) Said new object yields a slightly different vertex count, which means it cannot be used as morph object in my original application

 

My observations so far:
* The scaling appears to be correct on export/import.
* Comparing the old versus the new, the count of triangles / quads / faces is identical
* The count of vertices differs, however, with the old being 18208 and the new being 18018 in an example
* It doesn’t appear to matter how the original Wavefront object is grouped, just that in 3D-Coat I either end up with multiple object groups or only one. The end result appears to be the same.

 

Perhaps I am doing something wrong or missing something obvious. Does anyone have a hint as for what to look out for? As far as I know the “Tweak” room is supposed to keep the model intact (contrary to e.g “Voxel” room).

 

Thank you in advance

[Aleksey]

maybe you had multiple verticies in the same place and 3d coat merges them into one vertice?

 

like for example if you have a symmetrical object. and you are using a symmetry object which does not weld the points in the middle together. originally your mesh would count both the middle points from the left side and from the right side of the model. But 3d coat merges those middle points together, so you result in a reduced point count, but still the same amount of polygons?

 

try importing and exporting into 3d coat continuously and see if the point count keeps going down.

[Renpatsu]

This may be the case, but the question is how to avoid this then?

 

Not all workflows start and end in 3D-Coat. So if I already have a fully weight-mapped and rigged figure in another application, I'd love to take the object into 3D-Coat and create morphs. For that reason the object has to be taken "as is" on import and not to be altered. Is this possible? Is there a workaround for this? Does this need to be a "feature request"?

 

Creating objects right there in 3D-Coat and rig / weight-map afterwards in another application is all fine, but I don't want to reinvent the wheel in this case as the item already exists fully rigged in the end application.

[Aleksey]

turn off symmetry, import the model.

 

turn on virtual symmetry in 3d coat, work on the model. Then turn off virtual symmetry and export it out.

 

then in your main app turn symmetry back on.

 

ie when importing and exporting to 3d coat only work on half the model.

Edited January 4, 2014 by Aleksey

[Renpatsu]

Just importing the model, not doing anything to it and then exporting the model out of 3D-Coat already makes it different enough to not work anymore. The resulting object does not appear to be the same in this case as it misses vertices. Symmetry in 3D-Coat is off all the time for me at the moment.

[Aleksey]

i mean turn of symmetry in your host application ( if that is the problem)

 

once again this only works if my assumpting is correct that 3d coat is snapping the center verticies together.

 

maybe its a different problem...

 

maybe make a video so we can see?

[Renpatsu]

Perhaps this helps: Doing a diff between the object that was imported into and then exported supposedly completely unaltered (no tweaks, nothing) out of 3D-Coat did indeed reveal missing vertices in the object file. There are some rounding errors as well of course, but these should be neglectable.

 

Edit to add: Note that e.g. the 10.4454 ... vertex only exists once in the original object file, so it doesn't appear to be 3D-Coat merging duplicate vertices.

 

Original object:

v 9.37826 114.076 -4.46746
v 10.4454 111.8 -5.48152
v 8.63462 111.384 -6.28205
v 11.5887 112.076 -4.45886
v 8.97713 116.017 -4.20068
v 7.59801 115.857 -5.01588

Newly exported from 3D-Coat:

v 9.378261 114.075996 -4.467460
v 8.977130 116.016998 -4.200680
v 7.598010 115.857002 -5.015880

Edited January 4, 2014 by Renpatsu

[Aleksey]

no idea man.

 

sorry.

[Carlosan]

0001379: Imported obj versus tweaked exported obj - different vertex count ?

http://3d-coat.com/mantis/view.php?id=1379

 

mantis report open

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

Do you know Mantis? 3D Coats bug reporting / feature request website

[alvordr]

You might also consider just importing your model into the Voxel Room, altering the morphs as needed, there...and then going to the Retopo Room and importing your reference mesh as before.  It should ask to snap it to the surface of the morph in the Voxel Room and you're counts SHOULD be the same, assuming there isn't a bug in 3DC.  Then export the mesh as you have been.  Come to think of it, how have you been importing/exporting the changes?  Your import/export process might also reveal more useful information, both in 3D Coat and the other app.

Edited January 7, 2014 by alvordr

[Carlosan]

  Notes (0003454)
Andrew (administrator) 
2014-01-17 14:31
  Try to import for perpixel painting and ensire that welding is OFF in import settings.