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Collada: import does wrong transofrmations
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Description

blender collada importer seems to fail to parse transformations correctly. compared to SketchUp and Preview.app, it looks very different, I don't have a chance to test it with Maya, however my own collada parser (and Luxrender renderer) seems to show it correctly. that makes me think the bug is in blender, not in the data.

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This bug report doesn't contain enough information, please attach a collada file to demonstrate the problem, and specify the Blender version and operating system you tested with, thanks.

Please add the requested information.

Hi. I'm on holiday and don't have sample data here. Will attach it asap.

Any news on this? Low priority?

Wanted to add 2 Screenshots (~170kb each) with different Blender versions, but I am getting an error on submitting attachments:

Error
missing parameters

I had the same issue, this issue tracker is best described as: most sucky I ever seen

In the meantime I describe what I saw on screen... ;-)

Ubuntu Linux 10.04


blender_2_57_1_r36338.png
Blender 2.57.1 r36338:
After importing your out.dae there are huge chairs round a huge table and huge window and some huge rectangular faces.

Tried opening it with MeshLab (Version 1.2.2).
-> This looks the same...


blender_2_58_1_r38019.png
Blender 2.58.1 r38019:
After importing your out.dae all items look correctly in size but all the chair's upper parts are invisible.

(btw the tracker's monitoring feature doesn't work- monitored bugs are not shown in list)

While attachment upload still being broken, I posted the mentioned screenshots here:

http://imageshack.us/photo/my-images/835/blender2571r36339.png/

http://imageshack.us/photo/my-images/696/blender2581r38019.png/

Trying hint from irc channel #blendercoders
Attachments are said to work only when leaving a new comment in this field...

That's a progress, I didn't know about MeshLab. I'm still puzzled how come that in SketchUp, everything looks ok. And COLLADA is almost native to sketchup, so my guess it's support over there is a bit better then MeshLab's and Blender's

(Since exporting of Normals to obj-format is deactivated in Blender I use MeshLab to compute and store them to an obj-file. Just Export from Blender as Collada dae and import his in MeshLab. There you can export with normals to obj.)


Where did you get the Collada file (in the Attachments) from?
Did you model it yourself- if so: which program and version did you use?

Hi Chris, I'm not sure how is it related to OBJ. Do you mean the normals are wrong in the DAE file? It comes from our custom tool that converts FML (http://floorplanner.com/) to a COLLADA scene. Because those missing chair tops don't look like a bad normals, more of badly handled transformations I guess.

Hi Dusan, no. I mentioned OBJ solely as a reason why I am using MeshLab.

Concerning your issue:
Did you already try loading a DAE from your custom exporter with MeshLab to see if it loads correcty (sizes, chairs)?




You mentioned Sketchup- I had some issues with exported DAE from Sketchup. There were parts of a model (car) rotated (metal body) while others (interior, motor, tires) were in place.

Additionally some models were far off-center so that you have to scroll out some time to see them... (don't know if this is a bug in blender or just a bad model- but Sketchup displays it at center).

Added 4 attachments showing parts of a car model imported other than e.g. with MeshLab:
(although MeshLab gives a Warning on import, see Screenshot "Audi_MeshLab_Warning")

Audi_Blender_2_58_1_r38019.png
Audi_MeshLab_Warning.png
Audi_MeshLab_v1_2_2.png




Steps to reproduce (Ubuntu Linux 10.04):

1.) Load Sketchup 8 Model (.skp file) from this webpage:
http://sketchup.google.com/3dwarehouse/details?mid=83f205b7de8e65e517f9d94e6661a9ab

2.) Export it to Collada .dae file using Sketchup 8 (using Wine on Ubuntu)

3.) Import it to Blender 2.58a

4.) Import it to MeshLab 1.2.2 (with Render->Backface Culling checked in Menu afterwards)

Hi Chris, I just tried to load my DAE file into MeshLab and it's all wrong, however I don't really see MashLab as a reference point. I never heard of it before, it does not load the model correctly at all, it shows one big mess, without applying any transforms. SketchUp is well established and highly popular application, with COLLADA as it's de facto standard format, so for me it's important to see it loaded correctly in both SketchUp AND Blender. I don't care about MeshLab. The model loads 100% correctly in SU, and, say, 90% in Blender (missing chair tops). The model is combination of generated mesh (walls) and models made with SketchUp. So if there's a problem loading models from SketchUp in Blender, then this is it. I think it's important to fix this incompatibility, so that people can use models from SketchUp and 3D Warehouse. Let's not waste time with MeshLab and let's make it work in Blender right away. How can I help? Shall I checkout the sources, get C crash course, locate COLLADA importer and start hacking?

Hi Dusan, you might got me wrong: I don't see MeshLab as reference point either! I just mentioned it as a "second opinion". ;-)
I would appreciate Blender and all other tools implementing the full COLLADA specification flawlessly!
Well, I'm afraid this is still some way to go...

Blender imports COLLADA 1.4.1 AFAIK - but not all tags are supported.
Blender exports COLLADA 1.4.1 AFAIK with some data as a special "Blender profile".

Found these pages confering COLLADA in Blender:
http://wiki.blender.org/index.php/Dev:2.5/Source/Architecture/COLLADA
http://wiki.blender.org/index.php/Dev:2.5/Source/Architecture/COLLADA/Coverage


w.r.t. development: Can't help you here - I am just a "user". ;-)

I suggest you visiting IRC channel #blendercoders or contact Nathan Letwory (jesterking) as the person in charge for COLLADA support in Blender.

Does Sketchup have a full and flawlessly working COLLADA 1.4.1 exporter?

Eating my words: Exporting normals to OBJ works.
The export options for OBJ are now (i.e. Blender 2.5+) located in the file selector window to the left. Did not find them at first sight.
#-)
There you can have normals exported, too.

Some of your geometry is missing because Blender doesn't support it (yet), most notably that which is expressed in the .dae as <lines>. From what I can judge I'd say that otherwise everything imports fine with current trunk.(r39912 or later).

The file is pretty huge, so doing a detailed investigation is a bit hard. If you can manage to drop the amount of assets inside the .dae that would be very helpful.

I understand that the chair with its top is not properly done, but if you could make your scene as lean as possible: one chair showing the issue, nothing else. Maybe even lowpoly version of the models (chair and top).

Thanks.

Moving to todo for <lines> support.

Hi Nathan, please don't move it to any <lines> support, because it's not lines related. Yes there may be some lines in that file, but that's not what this bug report is about. I will narrow the data ASAP and post it here. thank you

Reopen on request by Dusan, waiting for smaller test file.

Attaching the model that doesn't import well. To verify, open it with SketchUp or MeshLab.

I'm trying to build trunk to see the changes in COLLADA import, but failing with:


Linking program ==> 'blenderplayer'
Linking program ==> 'blender'
Undefined symbols:
"_RE_engines_find", referenced from:
_rna_SpaceView3D_viewport_shade_itemf in libbf_rna.a(rna_space_gen.o)
ld: symbol(s) not found
collect2: ld returned 1 exit status
scons: *** [/Users/skrat/Workspace/blender-build/build/darwin/bin/blenderplayer] Error 1

Any progress on this? Is it related to transformations inside library_nodes?

Collada bugs are not being handled well so far,

for this reason they are all being set as \'TODO\' and linked from our wiki page.

http://wiki.blender.org/index.php/Dev:2.5/Source/Development/Todo/Import_Export#OpenCollada

This tracker item can still be updated with useful info and closed (removed from the page above) when fixed.

Hi,

I tried to load the two attached models (out.dae.zip and burostoel02.dae) in blender 2.66a, and have not noticed any transformation related problem, the scene graph seems ok. The chairs seem complete.