Blender 2.63 exporter question(s)

[Drongle McMahon]

Well, BMesh and BSurfaces finally made me decide to try to move on from good old Blender 2.49b. So I tried a few simple exports and read the Collada files. It appears (in Export for SL mode at least) that it triangulates ngons before export. However, it exports everything as a <polylist> with mixed quads and triangles. OK so far, but then I triangulated the mesh inside Blender and exported again. It still exports the quads as quads. This means that I cannot control the direction of triangulation. Can anyone (Gaia ?) tell me if there is a way to make it export triangulated quads as triangles? Where is the right place to discuss this sort of thing with the Blender/Collada developers, should that be necessary?

PS. So I deleted one of the ctriangles from each of the ex-quad faces (it's a 5-sided cylinder) and exported again. It strill has the quads! Importing into 2.49, the quads are still there!

So then I did various rounds of saving/opening exporting/importing in the two versions. Either route through 2.49 and back to 2.63 makes it export with triangles. So does simply saving, closing and reopening in 2.63 - so I have discovered the work-around for my own problem. Still, there does seem to be a bug there.

[Gaia Clary]

i just have tried to export a simple triangulated cube to .dae and reimport it back to blender:

 

• open fresh scene
• enter edit mode
• triangulate the cube (ctrl-t)
• go to object mode
• File -> export -> COLLADA
• remove default cube
• File -> Import -> COLLADA
• go to edit mode
• The triangles are preserved.

The right place to discuss this is to report it in the blender bug reporter or report / talk to me. I am helping to maintain the collada development in blender, mostly testing and poking the developers

Can you provide an example file where you see the reported problems and post it to http://projects.blender.org/ ?

[Drongle McMahon]

Tried to send you this in a private message, but private messaging seems to be broken for now.

Try...

• open fresh scene
• enter edit mode
• triangulate the cube (ctrl-t)
• File -> export -> COLLADA (file1.dae)
• go to object mode
• File -> export -> COLLADA (file2.dae)
• remove default cube
• File -> Import -> COLLADA
• go to edit mode

Then - file2.dae has the triangles, but file1.dae does not.

Saving the Blender file instead of going into Object mode has the same effect, fixing the triangles. It looks like the exporter is looking at an older version of the undo history when file1.dae is exported. I'll see if I can get this info in the right place. Im fed up with having to endlessly register for everything though!

I guess switching to object mode isn't a terrible burden, so it's not a big problem :-)

[Gaia Clary]

Yeah, thats a bug. I filed a report:

http://projects.blender.org/tracker/index.php?func=detail&aid=31256&group_id=9&atid=498

 

[Gaia Clary]

Your issue is fixed.

[Masami Kuramoto]

There used to be a separation between the object-level mesh (saved with the .blend file) and the internal EditMesh (now BMesh) structure which was transient and not accessible to Python. The object-level mesh would not be updated until the user switched from edit mode back to object mode. This is why there are two separate undo histories in Blender. Performing undo in object mode rolls back an entire edit session, while undo in edit mode is much more granular.

Blender's COLLADA exporter is no longer a Python script but may be subject to similar limitations. In order to be able to export an entire scene, it has to work at the object level. If I remember correctly, the Python-based exporter in 2.49 just enforced a switch out of edit mode in order to apply any pending edit operations. This may be the solution here, but I'm not sure if I want that old behavior back...

[Drongle McMahon]

Great. Thanks. You saved me the trouble. :matte-motes-grin: Now all we need is SL fixes at that speed.

[Gaia Clary]

It has been implemented as follows:

 

• push current edits to object
• do the export

You remain in the mode from where you started the export but you will get another entry in the object undo stack. I think this is an acceptable implementation.