Reading reaction forces from FEMEntity

[bahadir14]

Hi, I would like to read reaction forces from free falling cube, which is FEM material. I knew that it exist for rigid entities, but not sure that it exists for FEMEntity. Here is my full code:

---

import argparse

import numpy as np
import os
import torch

from dask.order import order
from mpmath import euler
from pygel3d.hmesh import minimize_dihedral_angle
from os import path
os.environ['PYOPENGL_PLATFORM'] = 'glx'
import genesis as gs

def main():
parser = argparse.ArgumentParser()
parser.add_argument("-v", "--vis", action="store_true", default=False)
args = parser.parse_args()

########################## init ##########################
gs.init(seed=0, precision="32", logging_level="debug")

########################## create a scene ##########################

scene = gs.Scene(
    sim_options=gs.options.SimOptions(
        dt=4e-3,
        substeps=2,
    ),
    #coupler_options=gs.options.CouplerOptions(
    #    rigid_fem=True,
    #),
    rigid_options=gs.options.RigidOptions(
        dt=0.01,
        gravity=(0,0,-9.8),
        enable_collision=True,
        constraint_solver=gs.constraint_solver.Newton,
        iterations=200,
        tolerance=1e-7,
        integrator=gs.integrator.implicitfast,
        #use_contact_island=True,
    ),
    fem_options=gs.options.FEMOptions(
        use_implicit_solver=True,
        damping=0.1,
    ),
    viewer_options=gs.options.ViewerOptions(
        camera_pos=(9.6, 4.8, 14.0),
        camera_lookat=(0.0, 0.0, 0.0),
        camera_fov=35,
        max_FPS=30,
    ),
    show_viewer=True,
    vis_options=gs.options.VisOptions(
        #visualize_mpm_boundary=True,
    ),
)
cam = scene.add_camera(
    res=(1280, 800),
    pos=(5.5, 6.5, 3.2),
    lookat=(0.5, 1.5, 1.5),
    fov=30,
    GUI=True,
)

plane = scene.add_entity(
    material=gs.materials.Rigid(),
    morph=gs.morphs.URDF(file="urdf/plane/plane.urdf", fixed=True),
)
E, nu = 1.e7,0.3
rho = 2700.0

obj1 = scene.add_entity(
    material=gs.materials.FEM.Elastic(
        E=E,
        nu=nu,
        rho=rho,
        model="linear",
    ),
    morph=gs.morphs.Box(
        pos=(0.0, 0.0, 5.0),
        size=(0.5,0.5,0.5),
    ),
    surface=gs.surfaces.Metal(
        color=(0.6, 1.0, 0.8, 1.0),
        vis_mode="visual",
    ),
)

scene.build()
cam.start_recording()

horizon = 1000
for i in range(horizon):
        #if i < 400:
            #obj1.set_dofs_velocity([0.0, -2.0, 0.0,0.0,0.0,0.0])

        scene.step()
        cam.render()
cam.stop_recording(save_to_filename="fem_rigid_entities.mp4", fps=60)

if name == "main":
main()

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I would be happy to see your answers :)