Gazebo 'load function' exception with dash in model name

Question

I'm following gazebo tutorial that covers connecting it to ROS. The tutorial is controlling velodyne sensor from ROS. I named the model as velodyne_hdl-32. I got this error

Model.cc exception occurred in the Load function

After some debugging, it seems the topic is not being established. After changing the model's name to my_velodyne, the error vanished. My question is what are the rules for naming topics?

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Originally posted by CroCo on ROS Answers with karma: 155 on 2021-04-05

Post score: 0

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Original comments

Comment by gvdhoorn on 2021-04-05:\

I'm following gazebo tutorial that covers connecting it to ROS

please always link to any tutorials you are following or pages you refer to. We don't know what you are doing otherwise.

Additionally: the question title is "Interesting problem with naming topic" right now, which is not very descriptive. You appear to have a very clear symptom, so it would be good to use that as a title (ie: "Gazebo 'load function' exception with dash in model name" or something like that).

Answer 1

My question is what are the rules for naming topics?

that would be these: wiki/Names.

Quoting the relevant part:

Valid Names

A valid name has the following characteristics:

1. First character is an alpha character ([a-z|A-Z]), tilde (~) or forward slash (/)
2. Subsequent characters can be alphanumeric ([0-9|a-z|A-Z]), underscores (_), or forward slashes (/)

''Exception'': base names (described below) cannot have forward slashes (/) or tildes (~) in them.

So - (dashes) are not legal.

however I'm not entirely convinced the problem you ran into is related to this.

Model.cc exception occurred in the Load function

this reads like an error directly from Gazebo, so I would suggest to post this on Gazebo Answers instead of here on ROS Answers.

If you do post there:

1. please post a link here in a comment so we can keep things connected
2. include the SDF and/or URDF that you tried to load in your question, as otherwise people on that forum will not be able to help you (they cannot 'see' what you see)

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Originally posted by gvdhoorn with karma: 86574 on 2021-04-05

This answer was ACCEPTED on the original site

Post score: 1