Remove dependency on THREE.js?

[jtbandes]

Thanks for publishing this package! I'm looking at integrating it into a project that doesn't currently use THREE.js for 3D rendering. I was interested in just using the URDF parsing parts, but since the package uses the Quaternion/Euler classes from three, I didn't see a way to do that. It would be great if the dependency was optional, or perhaps if the parsing were split out into its own package (maybe using something like gl-matrix for a smaller math library).

[gkjohnson]

Thanks for your interest! Three.js is used pretty extensively in the URDFLoader component between materials and instantiating joints and links so it's a bit more than just the quaternion and euler classes but others have asked in the past for something more agnostic.

I wouldn't be opposed to something like a URDFParser or URDFLoaderBase class that contains all the rendering engine-agnostic bits and returns something like simplified JSON representation of the joints, links, etc in the URDF that can then be instantiated with engine-specific set of objects. In that case I don't think gl-matrix would be needed because any math or rotation application can be deferred to the full instantiation stage.

Unfortunately I don't have the bandwidth to put the effort into refactoring right now, though. If you're interested in taking something like that on I'd be happy to talk it through and refine a plan and help get a PR going to get it merged.

[jtbandes]

Yep, a plain parser that just returns a JSON-like object is what I was thinking (something like this simple GLB parser I worked on a couple years ago – although that's simpler because a large part of the data format is already json).

Makes sense that this might be a bit of work to extract from the current code structure — for now, I'm going to try integrating three.js since we might eventually be interested in moving over the rest of the project as well. Thanks for the quick response!

[gkjohnson]

Sounds good -- I'm going to close this as a dupe of #173 for now, then.

Are you planning to use this for Cruise Automation projects / Webviz, then? I've used your Rosbagjs library in the past which has been very useful (I knew I recognized your icon from somewhere). Not sure if you're looking into parsing Xacro files as well as URDF but I've published a js xacro-parser package here that can be used to preprocess any Xacro URDF files before loading with this package.

[jtbandes]

Yep, I remember some of our conversations on rosbag.js back in the day 😄 I really appreciate the work you've done on these packages and being responsive to PRs!

I'm now working on Foxglove Studio, which started as a fork of Webviz, but is now a desktop app which allows for things like filesystem access and direct TCP connections to ROS graphs. URDF support is a common request!

The app has a lot of features and inertia in our current 3D panel, but we're open to / interested in eventually migrating to three.js — it'll just take a while. For now the URDF viewer will probably be a separate panel so we can get something working sooner, and visualizing the URDF alongside other markers and TFs and such will come later.