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CAD shadows

CAD shadows add a world-space sun and a projected shadow to CAD geometry. The feature is off by default. An application turns it on with the viewer options or with Cognite3DViewer.shadowsEnabled.

Turning shadows on also turns on the sun shading that matches them. A face gets brighter when it looks toward the sun and darker when it looks away, including on surfaces that are not covered by a cast shadow and on ghosted nodes. A fully covered surface is darkened and stays partly lit. Point clouds and 360 images are left unchanged.

The API is marked @beta.

Enable shadows​

Pass enableShadows when creating the viewer:

const viewer = new Cognite3DViewer({
  sdk: client,
  domElement,
  enableShadows: true
});

The same flag can be changed after the viewer exists. Assigning it requests a redraw:

viewer.shadowsEnabled = true;
viewer.shadowsEnabled = false;

The GPU resources for the shadow map are allocated the first time shadows are enabled. Turning them off keeps those resources until the viewer is disposed.

The examples application exposes the same switch in the Rendering folder as CAD shadows. Opening that application with ?shadows=true starts with shadows on.

Custom objects​

CAD geometry casts the shadow and receives it. A custom object does not, unless the application opts in.

viewer.addObject3D wraps the mesh in a CustomObject with receiveShadow left at its default, false. To receive the shadow, construct the CustomObject yourself, set receiveShadow to true, and add it with addCustomObject:

import { CustomObject } from '@cognite/reveal';

const floor = new CustomObject(planeMesh);
floor.receiveShadow = true;
viewer.addCustomObject(floor);

Reveal only applies that shadow to a thin, up-facing surface:

  • The mesh bounding box must be flat. Its shortest side is at most a quarter of its longest side.
  • After the mesh world transform, that short side must point mostly upward. Its world Y component must be greater than 0.75. A horizontal plane qualifies. A box or a vertical wall does not.
  • A material drawn on the back side, such as a skybox, stays on its own material, so the shadow does not cover the sky.