Instance Property

subdivisionLevel

The number of subdivisions SceneKit uses to smooth the geometry’s surface at render time.

Declaration

@property(nonatomic) NSUInteger subdivisionLevel;

Discussion

Surface subdivision is a technique for using low-detail geometry to generate a smooth surface for rendering. When you increase the subdivisionLevel value of a geometry, SceneKit automatically splits each face in the rendered surface, creating a more detailed, smoother geometry, as shown in . SceneKit performs this subdivision process at render time, preserving the original geometry data.

Figure 1

Rendering a subdivision surface

ubdividing a surface rounds away any sharp edges and corners in the geometry; however, such details may be important to a model’s design. To preserve edges, use the edgeCreasesElement property to identify edges and the edgeCreasesSource property to specify how smooth or sharp they should appear after subdivision. To preserve corners, include a geometry source whose semantic value is SCNGeometrySourceSemanticVertexCrease when creating the geometry.

The default subdivision level is zero, specifying no subdivision—SceneKit renders the geometry exactly as its vertex data specifies.

See Also

Smoothing and Subdividing Geometry

edgeCreasesElement

The geometry element identifying which edges of the geometry’s surface should remain sharp after subdivision.

edgeCreasesSource

The geometry source specifying the smoothness or sharpness of edges after surface subdivision.