rtcSetGeometryTessellationRate(3) Embree Ray Tracing Kernels 4 rtcSetGeometryTessellationRate(3)

rtcSetGeometryTessellationRate - sets the tessellation rate of the
  geometry

#include <embree4/rtcore.h>
void rtcSetGeometryTessellationRate(
  RTCGeometry geometry,
  float tessellationRate
);

The rtcSetGeometryTessellationRate function sets the tessellation rate (tessellationRate argument) for the specified geometry (geometry argument). The tessellation rate can only be set for flat curves and subdivision geometries. For curves, the tessellation rate specifies the number of ray-facing quads per curve segment. For subdivision surfaces, the tessellation rate specifies the number of quads along each edge.

On failure an error code is set that can be queried using rtcGetDeviceError.

[RTC_GEOMETRY_TYPE_CURVE], [RTC_GEOMETRY_TYPE_SUBDIVISION]