threejs-impl-shadows

Three.js shadows often flicker or disappear due to misconfigured shadow camera frusta or incorrect bias values. Properly setting mapSize, normalBias, and ensuring renderer and per-object castShadow flags are enabled resolves these issues.

To configure shadow maps for DirectionalLight and SpotLight, enable shadowMap on the renderer, set castShadow on the light, and adjust the shadow camera frustum. Tuning mapSize and bias ensures accurate shadow projection across the scene.

PCFSoft and VSM are Three.js shadow map types that offer varying degrees of edge softness and filtering. Choosing between them depends on scene requirements, with VSM providing smoother shadows but requiring careful bias tuning.

Yes, the shadow configuration workflow applies to Three.js r160 and later versions. It covers directional, spot, and point light shadows, including mapSize, camera frusta, bias, and per-object shadow flags for modern scenes.

Use CameraHelper to visualize the shadow camera frustum boundaries in Three.js. This debugging workflow reveals if objects fall outside the frustum, allowing you to adjust the near, far, and orthographic dimensions to capture shadows correctly.

Using alpha-test with shadow maps in Three.js can cause edge artifacts if bias and normalBias are not properly adjusted. Correctly configuring per-object shadow properties and shadow map tuning mitigates these visual limitations.