Pose3 return type not valid for pybind11

[willstott101]

Environment

• OS Version: Custom poky-based distro (via Ubuntu 20.04)
• Source or binary build: Source from 1bf1aa4e511d3efe0f97a6c14048a35dbcde26ce on sdf13

Description

• Expected behavior: Python bindings allow me to get resolved (joint) poses
• Actual behavior: PyBind11 cannot convert the type

Steps to reproduce

1. Load an sdf using the python module
2. Try to access a method that returns gz::math::v7::Pose3<double> such as SemanticPose.resolve

Output

>>> p.raw_pose()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Unable to convert function return value to a Python type! The signature was
	(self: sdformat.SemanticPose) -> gz::math::v7::Pose3<double>

Possible Solution

I suspect gz-math needs to provide python object access as described here: pybind/pybind11#616

This means:

• Dev headers for the gz-math python library
• Cmake config to allow linking against that python module
• libsdformat's python library linking against it and returning gz-math python types

I'm going to see if I can get that to work and will post an example if it does - but I don't think I'll have time to put together a proper PR.

[ahcorde]

Did you try to import from gz.math import Pose3d ?

[willstott101]

Ah no I didn't... that works. Thanks!

Should the sdformat library import that automatically?

[ahcorde]

it seems that is not bringing the dependency, I will try to review this when I have some time.

Feel free to open a PR and tag me if you find a solution.

[willstott101]

ok failing test here: https://github.com/willstott101/sdformat/runs/8225866161?check_suite_focus=true
Based on: willstott101@6e66c67

This seems to fix it: https://github.com/gazebosim/sdformat/compare/sdf13...willstott101:sdformat:devtool?expand=1
passing test: https://github.com/willstott101/sdformat/runs/8226155319?check_suite_focus=true

[ahcorde]

Hi @willstott101,

do you mind to open a PR with your fix ?

[willstott101]

#1130 Opened one - but haven't gone through all the red tape yet - might get round to that some time but really not that interested in filling in a bunch of forms

[ahcorde]

The fix is merged. Closing this