Gazebo | Ignition | Community
Ask Your Question

Revision history [back]

It's a bit hard for me to follow from the description what is going where. It would help if you provided an example SDF or even pseudo-SDF.

But in any case, let's see if some things are clear:

  • A model's pose is defined w.r.t. the world or its parent model.
  • A link's pose is defined w.r.t. its parent model. So if the parent model's pose changes, the global pose of its links change.
  • A joint's pose is defined w.r.t. its child link.
  • A joint's pose does not alter the pose of any links, it just places the constraint in a different position. So connecting links in different models with a joint doesn't change those link's poses, it only alters how they will move with respect to each other.
  • SDF, unlike URDF and TF, supports graphs, so you can end up with something which isn't a tree.