LoD3

LoD3 refers to the third level of detail in a series of progressively simplified meshes used to render 3D objects at varying distances. In common practice, models are created with multiple LOD stages, starting at LoD0 with full detail; LoD3 represents a low-polygon version intended for distant or less visible instances. The exact polygon count or vertex budget of LoD3 varies by model and by engine, and may be generated manually by artists or automatically via mesh decimation.

LoD switching is typically distance-based, using the object's bounding box to determine when the camera's distance exceeds a threshold; some pipelines use screen-space size or a combination of criteria. To avoid popping, some engines blend between LODs or use fading transitions. LoD3 may also be used with texture LODs or billboards for very distant objects.

In practice, LoD3 is chosen to preserve silhouette and key features while reducing shading and vertex processing. The goal is to reduce GPU workload with minimal perceptual loss. Generation methods include quadric error metrics decimation, edge collapse, and tools such as Simplygon, Blender's decimate modifier, or engine exporters. Many game engines (Unity, Unreal) manage LODs via an LOD group that defines switching thresholds and optional blending.

Limitations include potential visual popping, LOD seams, and inconsistencies with animation if not baked consistently across levels. Overall, LoD3 serves as a practical compromise for rendering distant or occluded objects efficiently, balancing fidelity and performance.