How to know the object/prim dimension created in Isaac Sim?

Omniverse Isaac Sim
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1

As topic.

Thank you!

2

Hi,
its possible to query local AABB and volume for a given rigid body collider. You can use this script to get the information:

import omni.usd
from omni.physx import get_physx_property_query_interface, get_physx_cooking_interface
from pxr import Usd, Gf, UsdGeom, UsdPhysics, UsdUtils, PhysicsSchemaTools, PhysxSchema, Sdf, UsdUtils
from omni.physx.bindings._physx import PhysxPropertyQueryRigidBodyResponse, PhysxPropertyQueryColliderResponse, PhysxPropertyQueryResult, PhysxPropertyQueryMode
import asyncio

async def main():
	usd_context = omni.usd.get_context()
	stage = usd_context.get_stage()
		
	selection = usd_context.get_selection()
	paths = list(selection.get_selected_prim_paths())
		
	stage_id = UsdUtils.StageCache.Get().Insert(stage).ToLongInt()
	
	def report_collider(collider_info : PhysxPropertyQueryColliderResponse):
		print("Volume for prim:  " + str(PhysicsSchemaTools.intToSdfPath(collider_info.path_id)) + " is: " +  str(collider_info.volume))
		print("aabb local min: " + str(collider_info.aabb_local_min)
		print("aabb local max: " + str(collider_info.aabb_local_max)
	
	for p in paths:
		prim_id = PhysicsSchemaTools.sdfPathToInt(p)
		get_physx_property_query_interface().query_prim(stage_id ,  prim_id,
			query_mode = PhysxPropertyQueryMode.QUERY_RIGID_BODY_WITH_COLLIDERS, 
			collider_fn = report_collider)
		await omni.kit.app.get_app().next_update_async()
	
	print("Done")

asyncio.ensure_future(main())

Select a rigid body and run the script in the script editor.
Regards,
Ales

3

I tried it, but the aabb local min and local max seem unchanged even if I change the dimension.

aabb local min: (-0.5, -0.5, -0.5)
aabb local max: (0.5, 0.5, 0.5)

may I know why?

4

The scale should not be part of it, so if you just scaled the object the aabb wont change.

5

I see. May I know how should I check the scaled object dimension?

6

You get the scale and muliply the provided aabb dimensions. You can get the scale of the prim like this:

        tf = Gf.Transform(xformable.ComputeLocalToWorldTransform(Usd.TimeCode.Default()))
        scale = Gf.Vec3d(tf.GetScale())
7

Thank you so much! May I know if we have any method that can check the object size not in the interactive script editor and Python script?

8

Where would you like to check the size? You can also use OVD:
https://docs.omniverse.nvidia.com/extensions/latest/ext_omnipvd.html
Capturing the simulation state and checking the created objects in PhysX SDK.

9

Oh, I want to check the object size in Issac Sim/Orbit in python script.

10

This python code can be run anywhere even as part of Sim/Orbit. If simulation already started you can just run the query, it should return the results instantly.