from jax import numpy as np from jax.numpy import linalg as la import elodin as el TIME_STEP = 1.0 / 120.0 G = 6.6743e-11 @el.system def gravity( graph: el.GraphQuery[el.TotalEdge], query: el.Query[el.WorldPos, el.Inertia], ) -> el.Query[el.Force]: def gravity_inner(force, a_pos, a_inertia, b_pos, b_inertia): r = a_pos.linear() - b_pos.linear() m = a_inertia.mass() M = b_inertia.mass() norm = la.norm(r) f = G * M * m * r / (norm * norm * norm) return el.SpatialForce(linear=force.force() - f) return graph.edge_fold( query, query, el.Force, el.SpatialForce.zero(), gravity_inner ) w = el.World() mesh = w.insert_asset(el.Mesh.sphere(0.2)) a = w.spawn( [ el.Body( world_pos=el.SpatialTransform(linear=np.array([0.8822391241, 0, 0])), world_vel=el.SpatialMotion(linear=np.array([0, 0, 1.0042424155])), inertia=el.SpatialInertia(1.0 / G), ), el.Shape(mesh, w.insert_asset(el.Material.color(25.3, 18.4, 1.0))), ], name="A", ) b = w.spawn( [ el.Body( world_pos=el.SpatialTransform(linear=np.array([-0.6432718586, 0, 0])), world_vel=el.SpatialMotion(linear=np.array([0, 0, -1.6491842814])), inertia=el.SpatialInertia(1.0 / G), ), el.Shape(mesh, w.insert_asset(el.Material.color(10.0, 0.0, 10.0))), ], name="B", ) c = w.spawn( [ el.Body( world_pos=el.SpatialTransform(linear=np.array([-0.2389672654, 0, 0])), world_vel=el.SpatialMotion(linear=np.array([0, 0, 0.6449418659])), inertia=el.SpatialInertia(1.0 / G), ), el.Shape(mesh, w.insert_asset(el.Material.color(0.0, 1.0, 10.0))), ], name="C", ) w.spawn( el.Panel.viewport( track_rotation=False, active=True, pos=[0.0, 5.0, 0.0], looking_at=[0.0, 0.0, 0.0], hdr=True, ), name="Viewport 1", ) w.spawn(el.VectorArrow(a, "world_vel", offset=3, body_frame=False, scale=1.0)) w.spawn(el.Line3d(b, "world_pos", index=[4, 5, 6], line_width=10.0)) sys = el.six_dof(TIME_STEP, gravity) sim = w.run(sys, TIME_STEP)