This page provides information on the Ornatrix Modifier.
generate w coord – When enabled, V-Ray will generate a W mapping coordinate that represents the position of the shaded point along the hair strands. Otherwise, the W coordinate is taken from the Ornatrix modifiers.
use global hair tree – When enabled, V-Ray will store the hair strands from all hair systems in the scene into a single raytrace acceleration structure at the start of each frame. This speeds up rendering especially when multiple hair systems are applied to the same object, however the entire acceleration structure is kept in RAM for the entire frame. Turning this option off will cause V-Ray to store each hair system into a separate acceleration structure which can be built on demand and destroyed when the dynamic memory limit is reached.
dynamic tessellation – This option instructs V-Ray to subdivide and smooth the hair strands before rendering. Strands closer to the camera are tessellated into finer segments so that they render smooth, while strands away from camera are simplified to reduce memory usage and speed up rendering. For more information, see Dynamic Tessellation example below.
edge length – Specifies the desired edge length, in pixels, of each final segment of the hair strands when dynamic tessellation is enabled. Smaller values produce smoother strands but take more memory and are slower to render. Larger values are faster to render and take less RAM, but may cause the hair strands to appear jagged. See the Dynamic Tessellation example below for more information.
The hair strands have 10 knots and the straight lines between the knots are clearly visible when dynamic tessellation is disabled.
The dynamic tessellation option is enabled and the strands appear much smoother.
Official Ornatrix web site: https://www.ephere.com/plugins/autodesk/max/ornatrix/