Axis and transform change drastically when pressing 'play simulation'

[ljburtz1]

Using IsaacSim 2023.1.1-rc.8 / KIT SDK 105.1.2
I have an imported robot (six wheels, modeled after the pragyaan rover)
The transforms of each component look good now that i added proper pivot (origin of axes were way off after the import from blender to omniverse)

When I press play, the robot moves slowly as expected (angular drives on each wheel joints)
However, as soon as the play button is pressed, the axis gizmo and the transform panel change drastically:

• see pictures → the gizmo moves several tens of meters
• see pictures → the translate:pivot in the transform property doesn’t change value but changes position

I don’t know if this is related but the physics cameras such as follow look / velocity / drone do not work as expected : they do not point to the rover but towards areas tens of meters off.

Why are the axis jumping on simulation start? Why do the follow cameras not follow the Body object?
Thank you so much for any pointers, happy to provide any other further information.

[ljburtz1]

note that the same behavior happens on a basic scene with just the rover and a ground plane

[rgasoto]

Pivots are not supported by the Physics API. You can notice in your screenshot that when simulation starts the pivot Operation goes below a bar - meaning that it is currently a transform operation that is disabled.

[ljburtz1]

thank you for the reply.
Do you know if supporting pivots in the physics API is on the roadmap?
Or is there a better way to avoid this issue? Specifically when importing a robot from another format to usd, I’ve noticed that the transforms are often widely offset (in both position and orientation). Would be glad to figure out a better workflow for importing/creating such assets