Source object - this is the source
geometry for the fur. You can click on this button only from the
Modify panel (and not from the
Create one).
Length - the length of the fur strands.
Thickness - the thickness of the strands.
Gravity - this controls the force that
pulls fur strands down along the Z-direction.
Bend - this parameter controls the
elasticity of the fur strands. When it is 0.0,
the strands are hard and are all straight lines. Greater values cause the
strands to bend (e.g. under the influence of gravity).
Sides - currently this parameter is
disabled. The fur is always rendered as polygons facing the traced ray;
normals are interpolated to create a smooth appearance.
Knots - fur strands are rendered as
several connected straight segments; this parameter controls the number of
segments.
Flat normals - when this option is
on, the normal of the fur strands does not
vary across the strand width. Although not very precise, this is similar to
how other fur/hair solutions work. It may also help with fur antialiasing,
making the job of the image sampler a little easier. When this option is
turned off, the surface normal varies across the
width of the strands, creating the illusion that the strands have
cylindrical shape.
Direction variation - this parameter adds
slight variation to the direction in which fur strands grow from the source
object. Any positive value is valid. This parameter should also depend on
the scene scale.
Length/Thickness/Gravity
variation - these add variation to the corresponding parameters.
Values are from 0.0 (no variation) to
1.0.
Distribution - determines the density of
strands over the source object:
Per face - specifies the number of fur
strands per face of the source object. Every face will generate the
specified number of fur strands.
Per area - the number of strands for a
given face is based on the size of that face. Smaller faces have fewer
strands, larger faces have more strands. Every face has at least one
strand. The size of the faces is taken at the frame, specified by the
Reference frame parameter.
Reference frame - When the
Distribution parameter is set to
Per area, this specifices the frame at which the
source object is captured to calculate the face area. The captured data will
be used throughout the entire animation to ensure that the number of strands
for a given face remains constant during animation.
Placement - determines which faces of the
source object will generate fur strands:
Entire object - all faces will generate
fur.
Selected faces - only selected faces (for
example with a MeshSelect modifier) will
generate fur.
Material ID - only faces with the
specified material ID will generate fur.
Generate W-coordinate - in general, all
mapping coordinates are taken from the base object. However, the W mapping
coordinate can be modified to represent the offset along the hair strands.
When this option is on, the W coordinate is the
offset along the hair strands (0.0 is the strand
base, and 1.0 is the tip). The U and V
coordinates are still taken from the base object.
Channel - the channel for which the W
coordinate will be modified, when the Generate
W-coordinate option is on.
You can control some aspects of VRayFur with
texture maps. These can be either bitmaps, or vertex color maps painted
directly on the source object.
Base map channel - some of the texture
maps represent vectors in texture space, where the x and y directions are
derived from the u and v directions of a texture mapping channel. This
parameter specifies which mapping channel is used.
Bend direction map - this is an RGB map
which specifies a bend direction of the fur strands, in texture space
(according to the specified Base map channel).
This is the direction in which the fur strands curve to (the amount of
curvature is also controlled by the Bend
parameter). The red component is offset along the u texture direction, the
red component is the offset along the v texture direction, and the blue
component is the offset along the surface normal.
Initial direction map - this is an RGB map
which specifies the initial direction of the fur strands, in texture space
(according to the specified Base map channel).
The red component is offset along the u texture direction, the red component
is the offset along the v texture direction, and the blue component is the
offset along the surface normal.
Length/Thickness/Gravity/Bend map - these
maps are multipliers for the corresponding parameters, where black is a
multiplier of 0.0, and white is a multiplier of
1.0.
Density map - this map is a multiplier for
the strand density. Black portions of the map correspond to zero density
(effectively no fur will be generated in these areas), and white represents
the normal strand density, as specified by the distribution parameters.
These parameters control the display of VRayFur
in the viewports.
Preview in viewport - turns
on or off the preview
of VRayFur in the viewports.
Max. hairs - the maximum number of hair
strands that will be represented in the viewport. This may help to speed up
the viewports in the case of very dense fur.
Automatic update - when
on, the viewport preview of the fur will be
updated automatically as the source object changes. However, this may slow
down the interactive work with the viewports; in this case, turn the option
off to disable the automatic update.
Manual update - click this button to cause
the viewport preview to be updated.
![[VRayFur parameters]](vray_for_3ds_max_manual/vrayfur/vrayfur.png)
