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Is it possible to create additional Collada meshes of LEGO NXT parts?

asked 2011-08-24 09:33:22 -0600

imcmahon gravatar image

updated 2014-01-28 17:10:17 -0600

ngrennan gravatar image

I have built a robotic arm in Lego Digital Designer (as well as the physical world), and run the resulting .lxf and .ldr files through the nxt_lxf2urdf package. I then roslaunch the robot and up come the motor/sensor topics. So far, so good. When I try to visualize the robot in RViz, it spits out a bunch of errors:

[ERROR] [1314217186.037324443]: Could not load resource [package://nxt_description/meshes/parts/3737.dae]: Unable to open file "package://nxt_description/meshes/parts/3737.dae".
[ERROR] [1314217186.063642125]: Could not load model 'package://nxt_description/meshes/parts/3737.dae' for link 'ref_103_link': OGRE EXCEPTION(6:FileNotFoundException): Cannot locate resource package://nxt_description/meshes/parts/3737.dae in resource group Autodetect or any other group. in ResourceGroupManager::openResource at /tmp/buildd/ros-diamondback-visualization-common-1.4.1/debian/ros-diamondback-visualization-common/opt/ros/diamondback/stacks/visualization_common/ogre/build/ogre_src_v1-7-1/OgreMain/src/OgreResourceGroupManager.cpp (line 753)

[ERROR] [1314217186.081540366]: Could not load resource [package://nxt_description/meshes/parts/3649.dae]: Unable to open file "package://nxt_description/meshes/parts/3649.dae".

and so on for about 10 Collada meshes. Looking at the nxt_lxf2urdf wiki page, it states:

Currently nxt_dscriptions has a subset of the ldraw.org parts library converted to Collada meshes, so not all parts will be modelled in rviz. We are still looking for ways to make converting the ldraw models to Collada.
Somewhere along the way, I must have used some parts in LDD that do not currently have Collada meshes. And that brings me to my question: Is it possible to create more Collada meshes of individual LEGO NXT parts? How were the original parts' meshes created?

Thanks!

Ian

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answered 2011-09-02 10:38:17 -0600

mmwise gravatar image

Yes you can. Go to http://www.ldraw.org get the lego files from the parts tracker then convert to STL using LDView (http://ldview.sourceforge.net/Downloads.html). You can use STL with the URDF. or you can import the STl into meshlab to generate the collada files.

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I am trying to do this (because 3707.dae is oddly not centered and is driving me nuts) but I'd like the .dae files I create to be of the same size as the ones at nxt_description package, but I can't get them that big. How should I do it? I have zero experience with 3D modelling...

Capelare gravatar imageCapelare ( 2012-05-16 07:47:46 -0600 )edit

Also, how do I extract the .png textures from LDraw's .dat files? Thanks!

Capelare gravatar imageCapelare ( 2012-05-16 07:49:20 -0600 )edit
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answered 2012-05-18 06:08:17 -0600

Capelare gravatar image

(I know this is not an answer, but I thought I shouldn't open a new question, so...)

Basically I wanted to know what I asked in the comments of the other answer:

I am trying to do this (because 3707.dae is oddly not centered and is driving me nuts) but I'd like the .dae files I create to be of the same size as the ones at nxt_description package or I'll have to use different scale tags for each link, but I can't get them that big. How should I do it? I have zero experience with 3D modelling...

Also, how do I extract the .png textures from LDraw's .dat files? Thanks!

Thanks again in advance.
Miguel.

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Asked: 2011-08-24 09:33:22 -0600

Seen: 990 times

Last updated: May 18 '12