# Revision history [back]

I think the problem is that you do not have a match between the collision name in base and the collision name in contact. Generate the sdf file with

gz sdf -p <your_filename>.urdf


and see if they match. The name generated in the sdf is a strange one. I see that you already discovered that it adds and extra -collision at the end.

Also, I found that this did not work for me:

<collision name="bump_sensor_collision_collision"></collision>


I had to use this format (as well as getting the name right, of course):

<collision>bump_sensor_collision_collision</collision>


I think the problem is that you do not have a match between the collision name in base and the collision name in contact. Generate the sdf file with

gz sdf -p <your_filename>.urdf


and see if they match. The name generated in the sdf is a strange one. I see that you already discovered that it adds and extra -collision _collision at the end.

Also, I found that this did not work for me:

<collision name="bump_sensor_collision_collision"></collision>


I had to use this format (as well as getting the name right, of course):

<collision>bump_sensor_collision_collision</collision>


I think the problem is that you do not have a match between the collision name in base and the collision name in contact. Generate the sdf file with

gz sdf -p <your_filename>.urdf


and see if they match. The name generated in the sdf is a strange one. I see that you already discovered that it adds and an extra _collision "_collision" at the end.end. In my urdf files it puts other things into the name as well.

Also, I found that this did not work for me:

<collision name="bump_sensor_collision_collision"></collision>


I had to use this format (as well as getting the name right, of course):

<collision>bump_sensor_collision_collision</collision>