This page contains information on the V-Ray HairFarm Modifier that can be used with the HairFarm plug-in.
When using V-Ray HairFarm Modifier on a Hair Farm object, you will have to disable native Hair Farm rendering by turning off the Use Hair Farm Renderer option in the Hair Display modifier. Otherwise the hair will be rendered by both V-Ray and Hair Farm.
Disable native Hair Farm rendering on the Hair Display (WSM) Parameters.
You can use any V-Ray materials on a hair object with the VRayHairFarmMod modifier, including Hair Material | VRayHairMtl and Hair Information Map | VRayHairInfoTex.
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 Hair Farm 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 to a separate acceleration structure which can be built on demand and destroyed when the dynamic memory limit is reached.
dynamic tessellation – 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.
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.
Official Hair Farm web site: http://www.cyberradiance.com/hairfarm/