The V-Ray Fur tab allows you to make any of the project materials appear shaggy by adding fur to it. The fur is generated only during render time and is not actually present in the scene.
To add V-Ray Fur on an object, find its corresponding material in the Material List of the V-Ray Fur tab and click the check box. This will enable V-Ray Fur for the current material and will make its settings editable.
Strands per area – Specifies the density of strands per area. The area units correspond to the currently selected Revit project units.
Length – Specifies the length of the fur strands.
Thickness – Specifies the thickness of the fur strands.
Taper – Adds a taper to the individual strands of fur. Increasing this value will make each strand thinner at its upper end and wider at its base.
Gravity – Controls the force that pulls fur strands down along the Z-direction.
Bend – Controls the elasticity of the fur strands. When set to 0.0, all strands are stiff and straight lines. Greater values cause the strands to bend (e.g. under the influence of the Gravity parameter).
Knots – Fur strands are rendered as several connected straight segments; this parameter controls the number of segments.
Direction Variance – Adds slight variation to the direction in which fur strands grow from the source object. Any positive value is valid. This parameter should be adjusted according to the scale of the scene.
Length/Thickness/Gravity Variance – Adds variation to the corresponding parameter. Values range from 0.0 (no variation) to 1.0.
Level of Detail – When enabled, V-Ray will generate less fur geometry for parts of the scene that are far away from the camera. This is done by decreasing the density of the fur strands and increasing their thickness. The level of detail function helps for conserving memory by decreasing the detail where it is too far to be visible.
Start distance – Specifies the distance from the camera at which V-Ray will start implementing the Level of detail adjustment. Up to this distance the fur will be generated as specified by the user. After that V-Ray will decrease the density and increase the thickness of the strand by a factor of two for every n units of space specified by the Rate parameter.
Rate – The rate at which the Level of detail adjustment is applied.