Quickstart¶

Real-time Rendering¶

Newton provides a simple OpenGL renderer for visualizing the simulation. The renderer requires pyglet (version >= 2.0) to be installed.

renderer = newton.utils.SimRendererOpenGL(model=model, path="Newton Simulator", scaling=2.0)

# at every frame:
renderer.begin_frame(sim_time)
renderer.render(state)
renderer.end_frame()

# pause the simulation (blocks the control flow):
renderer.pause = True

Keyboard shortcuts when working with the OpenGLRenderer (aka newton.utils.SimRendererOpenGL):

Keyboard Shortcuts¶
Key(s)	Description
`W`, `A`, `S`, `D` (or arrow keys) + mouse drag	Move the camera like in a FPS game
`X`	Toggle wireframe rendering
`B`	Toggle backface culling
`C`	Toggle the visibility of the coordinate system axes
`G`	Toggle ground grid
`D`	Toggle depth rendering
`I`	Toggle info text in the top left corner
`SPACE`	Pause/continue the simulation
`TAB`	Skip rendering to continue the simulation in the background (can speed up RL training while running the renderer)

USD Rendering¶

Instead of rendering in real-time, you can also render the simulation as a time-sampled USD stage to be visualized in Omniverse.

renderer = newton.utils.SimRenderer(model=model, path="simulation.usd", scaling=2.0)

# at every frame:
renderer.begin_frame(sim_time)
renderer.render(state)
renderer.end_frame()

# to save the USD stage:
renderer.save()

Example: Creating a particle chain¶

import newton

builder = newton.ModelBuilder()

# anchor point (zero mass)
builder.add_particle((0, 1.0, 0.0), (0.0, 0.0, 0.0), 0.0)

# build chain
for i in range(1, 10):
    builder.add_particle((i, 1.0, 0.0), (0.0, 0.0, 0.0), 1.0)
    builder.add_spring(i - 1, i, 1.0e3, 0.0, 0)

model = builder.finalize("cpu")

print(f"{model.spring_indices.numpy()=}")
print(f"{model.particle_count=}")
print(f"{model.particle_mass.numpy()=}")

model.spring_indices.numpy()=array([0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9], dtype=int32)
model.particle_count=10
model.particle_mass.numpy()=array([0., 1., 1., 1., 1., 1., 1., 1., 1., 1.], dtype=float32)