README: Should have cross-references between urdfdom_headers and urdfdom?

[EricCousineau-TRI]

Both the READMEs in this repo and urdfdom do not reference each other at the top-level, which is confusing. I don't know when I should make an issue for urdfdom_headers or urdfdom, esp. related to the specification vs. implementation or whatever.

It would be nice if there were explicit guidance on that:
https://github.com/ros/urdfdom_headers/tree/2acf769db0f70205efd612830e2b2f2807862d80
https://github.com/ros/urdfdom/tree/0da4b20675cdbe14b532d484a1c17df85b4e1584
https://github.com/ros/urdf/tree/52a4d5973c4fe8fc60f6ae09d532b8043ce46d28

Relates SDFormat repo split as well:
gazebosim/sdf_tutorials#2
gazebosim/sdf_tutorials#10 (issue template)

Motivated by these cross-repo issues:
#59
ros/urdfdom#138

[EricCousineau-TRI]

Ah, geez... Yet another repo?
https://github.com/ros/urdf/issues

[clalancette]

There's also https://github.com/ros/urdf_parser_py.git (for python) and https://github.com/ros/collada_urdf.git (which I believe is related, but I'd have to dig back into the tangled weave again to make sure).

I don't disagree that this is a mess, but it is unfortunately a difficult mess to fix. Some of the packages are in Ubuntu packages, and some are released on the ROS buildfarm, which makes it worse.

[EricCousineau-TRI]

Ooh, yeah. I remember taking some time a couple years ago to at least indicate which forks are old. Seems like house-cleaning may be in order again :P

And I'm not calling for the repos to merged / futzed around with.
Rather, just for their explicit purposes to be called out (via README.md and an issue_template.md) so people can know when to look at one vs. the other (or realize that one of the repositories is effectively a meta-package).

It's really confusing as a user (and sometimes contributor) to somehow have to gain / get tribal knowledge to know what's going on, when it's not that hard to document?

[huangzonghao]

Yeah, can't agree more here. Took me sometime to figure out the relation between urdfdom and urdf

[clalancette]

For what it is worth, @IanTheEngineer recently updated the documentation to more clearly show the relationship. It's available here: http://wiki.ros.org/urdf