Isaac Sim 2021.1 import URDF

Isaac Sim 2021.1.0-rc.15

How to properly import custom robot arm URDF, set up physics and control it via Python?

I imported the following urdf into the stage:

but after I press the play button, some links of the robot arm are disappeared…

@xuzy70

The issue is that in the urdf under the limit section, all velocity limits for the joints are set to zero
if you change this:
velocity = "0"
to something like
velocity = "100"
and re-import, the robot will import correctly.

I’ve added a new warning to the code which will be in the next release:

[Warning] [omni.isaac.urdf] Joint joint2_to_joint1 has a velocity limit of 0.000000 which is <=0, Value will be ignored unless it is > 0
[Warning] [omni.isaac.urdf] Joint joint3_to_joint2 has a velocity limit of 0.000000 which is <=0, Value will be ignored unless it is > 0
[Warning] [omni.isaac.urdf] Joint joint4_to_joint3 has a velocity limit of 0.000000 which is <=0, Value will be ignored unless it is > 0
[Warning] [omni.isaac.urdf] Joint joint5_to_joint4 has a velocity limit of 0.000000 which is <=0, Value will be ignored unless it is > 0
[Warning] [omni.isaac.urdf] Joint joint6_to_joint5 has a velocity limit of 0.000000 which is <=0, Value will be ignored unless it is > 0
[Warning] [omni.isaac.urdf] Joint joint6output_to_joint6 has a velocity limit of 0.000000 which is <=0, Value will be ignored unless it is > 0

@xuzy70 we just released a bugfix release yesterday (2021.1.1) can you try it out and see if the issue is resolved?

Solved! Thanks a lot