Ray-Traced Rendering

The ray-traced render mode lights the running twin by tracing rays on the graphics card instead of approximating light with shadow maps. Light bounces between the parts, metal and glass reflect their surroundings, transparent covers let light through, and shadows in corners and gaps fall out of the traced light. You keep working while it renders: you navigate, run the simulation and operate the model, and the image refines whenever the view is still.

For offline video at full quality, use Cinematic Videos instead. They path trace every frame for seconds; the ray-traced mode traces a little every frame and stays interactive.

How it works

• Hybrid rendering. The viewer draws the model as usual. A WebGPU compute shader then traces the lighting for the visible surfaces against a copy of the scene on the GPU.
• Bounced light. Each sample follows one diffuse bounce by default (the renderer supports up to three) and one glossy reflection, so colours spill onto neighbouring surfaces and polished parts mirror the scene.
• Transparency and shadows. Transparent materials dim the rays that pass through them instead of blocking them. Soft shadows and the darkening in corners come from the traced light, so the shadow map and ambient occlusion are switched off in this mode.
• Environment light. The scene is lit by the environment of the Visual tab and by emissive surfaces. There is no separate key light.
• Temporal accumulation. Every frame traces a share of the pixels and blends the result with the samples of the last few frames at the same pixel. With a still camera most of the grain fades within moments, though some fine noise can remain. When the camera or parts move, the blended history shows as short trails until it catches up.

Requirements

• The Commercial edition. The mode is also included in the public demo.
• A desktop browser with WebGPU, such as current Chrome or Edge. See Browser & GPU setup.
• The WebGPU renderer backend. The viewer ships on WebGL; without WebGPU the mode is not offered.
• A dedicated GPU is recommended. Integrated graphics run the mode, but large plants refine slowly.

Switch it on

1. Open Settings ▸ Visual ▸ Renderer and set Backend to WebGPU (experimental). The viewer reloads.
2. Open the render-mode menu in the view controls in the bottom right corner and choose Ray traced. The same choice is listed under Settings ▸ Visual ▸ Render Mode.
3. Wait for the first image. On the first switch the viewer loads the ray tracer and builds the scene copy on the GPU, which takes a few seconds on large models.

To leave the mode, choose Shaded in the same menu. To return to WebGL, set Backend back to WebGL or open the viewer with ?renderer=webgl.

Known limits

The ray-traced mode is a beta. These limits are known:

• Noise on fast motion. Fast camera moves and fast-moving parts show grain and short trails until enough samples have accumulated again. A motion-aware filter is not available yet.
• Cost rises on long runs. After a few minutes of continuous simulation with many moving parts, the frame time can rise. For long-running presentations, check the frame rate after a few minutes and switch to Shaded if it drops.
• WebGPU is experimental in the viewer. Some features use fallbacks on the WebGPU backend; see WebGL and WebGPU.
• No floor mirror and no bloom. The floor reflection, bloom and the toon look are off in this mode.

See also

• Cinematic Videos — path-traced video frames for presentations
• Settings — render mode, environment and renderer backend
• Browser & GPU setup — make the browser use the right graphics card