Softimage exports invalid Collada files?

[Dan Yargici]

So after much head scratching concerning the Collada importer in Blender, I stumbled across this bug report by Thomas Volkmann.

http://projects.blender.org/tracker/?group_id=9&atid=498&func=detail&aid=31089 

It would seem the issue actually lies with Softimage/Crosswalk....

It would be great if there were an option to export safer, more basic, 'vanilla' collada files in the exporter IMO.  Half the time you just want to transfer a camera and some geometry...

The relevant quote:

The collada-output generated by softimage seems to violate the Collada 1.4.1 specifications:

According to the collada specifications from http://www.khronos.org/files/collada_spec_1_4.pdf (see page 3-7) :

The common <param> (core) name attribute for animation translations may contain a <param> with name="X|Y|Z" wich specify the 3 cartesian coordinates.

Blender uses name="X|Y|Z" according to the specifications:

<animation>
<source>
<technique_common>
<accessor>
<param name="X|Y|Z" />
</accessor>
</technique_common>
</source>
</animation>

Softimage uses name="VALUE" for all 3 coordinates:

<animation>
<source>
<technique_common>
<accessor>
<param name="VALUE" />
</accessor>
</technique_common>
</source>
</animation>

thus the most important information (which coordinate shall we use) has been corrupted.

However i believe that softimage has added a lot of <extra> information enclosed in <technique profile="XSI"> and it looks very much like the true animation data is provided in this extra datablock. I guess that Blender does not support the XSI profile ?

====

Proof :

1.) I have modified the softimage dae file by replacing the 3 occurances of name="VALUE" by name="X", name="Y" and name="Z" respectively. this imports into blener and the animation is intact.

2.) I have tried to import the original collada file from softimage into meshlab. That failed.

3.) have tried to iport the original collada file from Blender into meshlab. That worked. 

[Min Rui Tan]

Do you have actual scene files that you have problems with?

If Blender only supports name="X|Y|Z", then it might be their(or OpenCollada's) limitation.
For <sampler> elements in COLLADA, you can see from the specs page 136, the param name should not matter.
The X and Y values should be processed from the INPUT and OUTPUT semantics rather than whatever the name attribute is.

-Min Rui

[Dan Yargici]

Thanks, Min Rui.

That's interesting, would you mind if I quote your reply into that discussion in the Blender bug tracker?  If it is indeed the fault of the Blender importer I should point it out. :)

DAN

[Min Rui Tan]

Sure.

From: softimag...@listproc.autodesk.com [mailto:softimag...@listproc.autodesk.com] On Behalf Of Dan Yargici
Sent: Monday, June 11, 2012 1:12 PM
To: soft...@listproc.autodesk.com
Subject: Re: Softimage exports invalid Collada files?

Thanks, Min Rui.

That's interesting, would you mind if I quote your reply into that discussion in the Blender bug tracker? If it is indeed the fault of the Blender importer I should point it out. :)

DAN

On Mon, Jun 11, 2012 at 6:56 AM, Min Rui Tan <minru...@autodesk.com<mailto:minru...@autodesk.com>> wrote:
Do you have actual scene files that you have problems with?

If Blender only supports name="X|Y|Z", then it might be their(or OpenCollada's) limitation.
For <sampler> elements in COLLADA, you can see from the specs page 136, the param name should not matter.
The X and Y values should be processed from the INPUT and OUTPUT semantics rather than whatever the name attribute is.

-Min Rui

[Thomas Volkmann]

This is some good information! I can add it to the Blender Bugtracker, then you don't have to create an account just to do it.

cheers,

Thomas

Dan Yargici <danya...@gmail.com> hat am 11. Juni 2012 um 07:12 geschrieben: