collada

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markusi
Posts: 11
Joined: 19 Apr 2013, 09:47

collada

Post by markusi » 24 Apr 2013, 16:35

hi,

collada importer and exporter shows strange behaviour.

I want to use collada as an interchange format with v-rep (rather than writing an own importer for our format since if I manage to write an exporter to collada i maybe can use the workcells in blender as well).

therefore I started with exporting a new workcell in v-rep followed by importing it again. Apart from looking strange :

What does a .dae file have to look like in vrep ?

br

markus

coppelia
Site Admin
Posts: 7396
Joined: 14 Dec 2012, 00:25

Re: collada

Post by coppelia » 24 Apr 2013, 16:47

Hello Markus,

Collada is a very complex format that supports (or is supposed to) many features. There are also several versions of Collada, and it is extremely difficult to support everything. So if possible, use a simpler format.

If you however want to use the collada importer/exporter, you can look at the source code to see what features are supported (programming/v_repExtCollada). But basically:
  • Scene nodes with their transformations and hierarchy
  • Materials or rather colors
  • Polygon and triangle groups
Meshes that are described with something different than polygon groups or triangle groups are ignored (e.g. splines).

If possible, send us the file that is causing trouble, so that we can have a look at it.

Cheers

markusi
Posts: 11
Joined: 19 Apr 2013, 09:47

Re: collada

Post by markusi » 25 Apr 2013, 06:39

thanks for the offer,

in order to find out the required file format I tried to import a moreless blanc skelletton of a .dae file -> that didn't work -> that's why I asked what has to be contained in minimum.

<?xml version="1.0"?>
<COLLADA>
<library_effects>
</library_effects>
<library_materials>
</library_materials>
<library_geometries>
</library_geometries>
<library_visual_scenes>
</library_visual_scenes>
<scene>
<instance_visual_scene url="#world"/>
<scene>
<COLLADA>

next I tried was to save and reimport a new v-rep cell -> I posted in this section because the scene looks strange after doing that.

.ttt file format is binary -> what other file format do you recommend ? do you recommend to write an importer for our own format rather than using an "open" format ?

coppelia
Site Admin
Posts: 7396
Joined: 14 Dec 2012, 00:25

Re: collada

Post by coppelia » 25 Apr 2013, 09:50

Hello Markus,

How did the scene look strange after reimporting? Is it a problem of color, or meshes?
Yes, V-REP format (*.ttt) is binary.
Now it really depends how often you have to import something. If it is just occasionally, then you can use the other formats such as:
  • 3ds
  • stl (binary and text)
  • obj
  • dxf
  • URDF
To streamline a process, it sometimes makes sense to write his own exporter/importer. An importer in V-REP can be written using a plugin, or an add-on, and many API functions such as:
Writing your own exporter/importer gives you much more flexibility.

Cheers

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