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dartsim / dart

DART: Dynamic Animation and Robotics Toolkit
http://dartsim.github.io/
BSD 2-Clause "Simplified" License
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URDF parser shouldn't treat multitree as an error #1267

Closed jslee02 closed 5 years ago

jslee02 commented 5 years ago

URDF parser errors when the root link is "world" (treated as a keyword) and the root link has multiple children. However, DART supports multitree in a skeleton. Moreover, this logic continues with this error and yet surprisingly it successfuly creates multitree anyway.

We should make it clear that it's not an error and update the logic accordingly.

mxgrey commented 5 years ago

I think URDF wasn't designed to support multi-tree robot descriptions, so the original author of this (which wasn't me; all I did was refactor this code) decided that we should consider instances of multi-tree URDFs to be an error.

There are a few things about our URDF parser that aren't really standard, though, so I'm completely in favor of supporting a superset of the URDF standard.

jslee02 commented 5 years ago

I think URDF wasn't designed to support multi-tree robot descriptions

That is true. So I think we should either return nullptr with an error message for that case (which is not the current implementation) or allow multi-tree robot with a warning message saying it's not the standard.

I'm inclined to the second option.

mxgrey commented 5 years ago

The second option sounds good to me too :+1:

jslee02 commented 5 years ago

Resolved by #1270