[Enhancement] Relative References

[miquelmassot]

Please add an option to position objects in a scene relative to other objects from an urdf file.

[marioprats]

Sounds useful. Should these objects keep their relative pose when one is updated? Or it's just for easy placement, and then the objects are independent?

[miquelmassot]

I think that both are useful. Maybe there should be a boolean variable asking whether or not to move with the parent object rather than just computing a relative-to-global position and storing it.

[perezsolerj]

I was thinking to solve this issue not in a hacky way, and I think we should rewrite some code and merge position and orientation inside a tag called pose (for example) and add two attributes to pose tags:
relativeTo: To make it easier to place objects just using relative reference to other object
AttachedTo: Relative permanent position, like vehicle's sensors do right now.

In my opinion it will make easier the parsing code in ConfigXMLparser as sensors vehicles and object's pose would be the same way. And it's much more intuitive than adding another tag relativeTo in objects.

So at the end would be something like:

Global position object
< pose >
< position >
< x > -0.2 < /x >
< y > 0 < /y >
< z > 2.0 < /z >
< /position >
< orientation >
< r > 0 < /r >
< p > 0 < /p >
< y > 0 < /y >
< /orientation >
< /pose >

relative to other object/node
< pose relativeTo="otherObject" >
( .... )
< /pose >

attached to other object/node
< pose attachedTo="otherObject" >
( .... )
< /pose >

This will require some minor changes in your scenes, but I thinks it's worthy. What do you think? I guess Miquel can't answer right now but maybe the rest... ;)

Edited to write XML as it should