Table of Contents

This page provides information on the Ornatrix Modifier.


The VRayOrnatrixMod modifier can be used to render hair strands produced by the Ornatrix plugin by Ephere. The VRayHairMtl material can be used to further control the appearance of the hair.

It is strongly recommended to use hair materials for hair-based objects used for simulating hairs.

UI Path: ||Select geometry|| > Modifiers menu > V-Ray > V-Ray Ornatrix Mod

||Select geometry|| > V-Ray menu > Create > Modifiers > V-Ray Ornatrix Mod

||Select geometry|| > Modifiers menu > V-Ray > V-Ray Ornatrix Mod

Image courtesy of Ludovic Lieme


Generate W coord – When enabled, V-Ray generates 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 stores 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 causes 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 – 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.

Min pixel width – Sets the minimum pixel width for each hair strand to help ensure samples are taken consistently between pixels. A value of 0 means no minimum width is applied, but increasing it makes rendering the strands consistent. This additional calculation increases render times, but smooths the hair width. Note: Values are limited to 2. Larger values (closer to 2) can significantly increase render times.

Example: Dynamic Tessellation

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.


  • Use the Ox Render Settings modifier to control the thickness of the strands; any settings in the Ornatrix atmospheric effects are ignored.

  • Unless you use the Use global hair tree option, the generated strands are dynamic geometry; as such, they respect the Dynamic memory limit setting in the V-Ray raycaster section. If you have lots of hair strands and Use global hair tree is disabled, it is recommended to increase this value.

Official Ornatrix web site: https://www.ephere.com/plugins/autodesk/max/ornatrix/