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Collada: Export problem when activating transparency
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Description

This problem occurs in every 2.57 compilation 32 & 64 bit (os windows 7),

when a collada file exported with these builds has transparency activated and it is imported into other program, normals dont work properly or the transparency is completly lost.

See the difference using the same simple mesh (transparency on) and default settings exported under 2.56 vs 2.57 in the attached files.

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Does this mean that 2.56 still had proper export?

hep, accidently pressed save changes after all, already noted from the attached files.

to the first question, yep, I'm using the 2.56 version to export every collada files (if they got transparency objects) and importing them in other programs, augmented reality... without any problem.

"Update"

Still don't working on the 2.58 release.

Ok, finally dove inside the .dae files, and I think the shaders here are the ones causing the problems.

In the 2.56 dae the material is a <lambert>, but in 2.57 dae this is a <phong>. There was a change regarding the export of materials between 2.56 and 2.57. For COLLADA lambert cannot have specular, so the change was to see if a material has specular set. Only when specular is off a lambert shader would be exported as a lambert shader.

Please try disabling specular for your material and re-export. Your file will probably behave better then.

Thanks.

Hi, sorry for the delay, I have been trying to export in other formats, .obj -- .fbx and I think the bug apply to many other formats, so maybe it's the way blender is exporting models with transparency activated since 2.57 version. I can attach a simple example, I have been using blender for developing 3D content to import in augmented reality software, but I still need to export the models with transparency on using the 2.56 version due to the extrange things that occurs in those surfaces.
--> Files attached: .blend + .dae + .obj + fbx + jpg's<--
Thanks!

I'm renaming to general export problem with transp, since this is not anymore COLLADA specific.

This report should be split up so each format can be dealt with separately, to say "transparency fails with dae / fbx / obj"


fw('\n\t\t\tProperty: "TransparencyFactor", "double", "",%.4f' % (1.0 - mat_alpha))

... which shows up in you're file as:
Property: "TransparencyFactor", "double", "",0.6000


In you're MTL file there is "d 0.400000" which means dissolve, which OBJ uses for alpha.

So to me it seems that the augmented reality software just isnt reading values from blenders OBJ / FBX files.

renaming report again :)

The strange thing is that all these issues occurs after 2.56 build, not only in the agumented reality software, you can do a simple test, export a geometry using blender 2.56 into other 3D program, i.e. Sketchup, and see the difference with newest builds. You can see the result in the attached file "No_transparency.jpg".

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.

From what i read here this is not necessarily a Collada Issue but a general issue maybe related to materials ?

Hi all,
I have been running through this very same problem of exporting COLLADA from Blender with transparency and loading to other softs where transparency is lost.
My knowledge of Blender is low but I am on Mac and I can tell you that transparency is fine when reading the exported COLLADA file with the "basic" Preview (OS10.6.8).
Quite surprising to me.
Maybe that can give you some hints to solve this problem ?

We at MakeHuman.org are also hitting against the issue of transparency property in DAE files not being respected by the importer.
Cross reference: http://bugtracker.makehuman.org/issues/679

Having a fix for this issue would benefit both Blender and MakeHuman a lot.