How can i add deformable objects in a python standalone script?

[ksterx]

Is there a good way to add deformable objects within a python standalone script?
I saw in the tutorial how to add such an object within an extension, but I could not figure out how to add it in a standalone script.
For example, is there code to add an object set up as a deformable object in one USD file to another world?
Or is there a way to set up an object as a deformable object after loading the object described in the USD file?

[AlesBorovicka]

Hi,
yes you should be able to do so, you can check the deformable body demo and display the script (most physics demos are generated through a python code). You can enable the demos - Window->Simulation->Physics->Demos.
I am pasting here the code snippet anyway:

import omni
from omni.physx.scripts import deformableUtils, physicsUtils
import omni.physxdemos as demo
import omni.usd
from pxr import UsdGeom, UsdLux, Gf, UsdPhysics


class DeformableBodyDemo(demo.Base):
    title = "Deformable Body"
    category = demo.Categories.DEFORMABLES
    short_description = "Deformable body scene setup"
    description = "This snippet sets up a deformable body scene"

    @staticmethod
    def create_sphere_mesh(stage, target_path):
        _, tmp_path = omni.kit.commands.execute("CreateMeshPrim", prim_type="Sphere")
        omni.kit.commands.execute("MovePrim", path_from=tmp_path, path_to=target_path)
        omni.usd.get_context().get_selection().set_selected_prim_paths([], False)
        return UsdGeom.Mesh.Get(stage, target_path)

    def create(self, stage):
        default_prim_path, scene = demo.setup_physics_scene(self, stage)
        room = demo.get_demo_room(self, stage, zoom = 0.5)

        # Create sphere mesh used as the 'skin mesh' for the deformable body
        skin_mesh = self.create_sphere_mesh(stage, default_prim_path + "/deformableBody")
        physicsUtils.set_or_add_translate_op(skin_mesh, translate=Gf.Vec3f(0.0, 0.0, 300.0))
        physicsUtils.set_or_add_orient_op(skin_mesh, orient=Gf.Quatf(0.707, 0.707, 0, 0))
        physicsUtils.set_or_add_scale_op(skin_mesh, scale=Gf.Vec3f(2.0, 2.0, 0.5))

        color = demo.get_primary_color()
        skin_mesh.CreateDisplayColorAttr().Set([color])

        # Create tet meshes for simulation and collision based on the skin mesh
        simulation_resolution = 10

        # Apply PhysxDeformableBodyAPI and PhysxCollisionAPI to skin mesh and set parameter to default values
        success = deformableUtils.add_physx_deformable_body(
            stage,
            skin_mesh.GetPath(),
            collision_simplification=True,
            simulation_hexahedral_resolution=simulation_resolution,
            self_collision=False,
        )

        # Create a deformable body material and set it on the deformable body
        deformable_material_path = omni.usd.get_stage_next_free_path(stage, default_prim_path + "/deformableBodyMaterial", True)
        deformableUtils.add_deformable_body_material(
            stage,
            deformable_material_path,
            youngs_modulus=10000.0,
            poissons_ratio=0.49,
            damping_scale=0.0,
            dynamic_friction=0.5,
        )
        physicsUtils.add_physics_material_to_prim(stage, skin_mesh.GetPrim(), deformable_material_path)

Regards,
Ales