V-REP fails to load certain URDF and SDF files

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ahundt
Posts: 112
Joined: 29 Jan 2015, 04:21

V-REP fails to load certain URDF and SDF files

Post by ahundt »

I tried to load the urdf and sdf files provided for bullet3 example data:
https://github.com/bulletphysics/bullet ... /kuka_iiwa

When I try to load kuka_with_gripper.sdf I get the following error:

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<sdf>: <world>: sub element gravity not found

In model.urdf vrep seems to choke on the relative paths to the meshes:

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URDF import operation started.
There are 7 joints.
ERROR: there is no joint with name ''
There are 8 links.
Creating link 'lbr_iiwa_link_0'...
ERROR: neither mesh file 'meshes/link_0.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_0.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_0.stl' nor '' do exist.
ERROR: failed to create the mesh 'meshes/link_0.stl' or '' with extension type 4
ERROR: there is no joint with name ''
Creating link 'lbr_iiwa_link_1'...
ERROR: neither mesh file 'meshes/link_1.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_1.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_1.stl' nor '' do exist.
ERROR: failed to create the mesh 'meshes/link_1.stl' or '' with extension type 4
Creating link 'lbr_iiwa_link_2'...
ERROR: neither mesh file 'meshes/link_2.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_2.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_2.stl' nor '' do exist.
ERROR: failed to create the mesh 'meshes/link_2.stl' or '' with extension type 4
Creating link 'lbr_iiwa_link_3'...
ERROR: neither mesh file 'meshes/link_3.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_3.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_3.stl' nor '' do exist.
ERROR: failed to create the mesh 'meshes/link_3.stl' or '' with extension type 4
Creating link 'lbr_iiwa_link_4'...
ERROR: neither mesh file 'meshes/link_4.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_4.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_4.stl' nor '' do exist.
ERROR: failed to create the mesh 'meshes/link_4.stl' or '' with extension type 4
Creating link 'lbr_iiwa_link_5'...
ERROR: neither mesh file 'meshes/link_5.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_5.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_5.stl' nor '' do exist.
ERROR: failed to create the mesh 'meshes/link_5.stl' or '' with extension type 4
Creating link 'lbr_iiwa_link_6'...
ERROR: neither mesh file 'meshes/link_6.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_6.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_6.stl' nor '' do exist.
ERROR: failed to create the mesh 'meshes/link_6.stl' or '' with extension type 4
Creating link 'lbr_iiwa_link_7'...
ERROR: neither mesh file 'meshes/link_7.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_7.stl' nor '' do exist.
ERROR: neither mesh file 'meshes/link_7.stl' nor '' do exist.
ERROR: failed to create the mesh 'meshes/link_7.stl' or '' with extension type 4
There are 0 sensors.
URDF import operation finished.



According to the SDF definition, gravity is optional:
http://sdformat.org/spec?ver=1.6&elem=link#link_gravity

Also, I tried putting the stl mesh files in the exact same folder as the urdf (rather than in the meshes folder) on the assumption that there was a and the files were still not found.

In case this is the fault of the models themselves, I created a corresponding issue in the bullet3 github repo:

https://github.com/bulletphysics/bullet3/issues/1156

coppelia
Site Admin
Posts: 10336
Joined: 14 Dec 2012, 00:25

Re: V-REP fails to load certain URDF and SDF files

Post by coppelia »

Hello,

yes, the SDF importer is a minimal implementation of the SDF specifications, and not all elements/attributes are currently supported.
The URDF plugin on the other hand is known to have several issues unfortunately. We hope to be able to find time to look at it, but are also thankful for anyone who would help us out here, since we have several more prioritized items to handle.

Cheers

fferri
Posts: 1193
Joined: 09 Sep 2013, 19:28

Re: V-REP fails to load certain URDF and SDF files

Post by fferri »

ahundt wrote: When I try to load kuka_with_gripper.sdf I get the following error:

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<sdf>: <world>: sub element gravity not found
According to the SDF definition, gravity is optional:
http://sdformat.org/spec?ver=1.6&elem=link#link_gravity
You are reading another part of the specification. It's gravity within the world element: http://sdformat.org/spec?ver=1.6&elem=w ... ld_gravity and the spec says it's required. Apparently the model file is wrong.

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