Using VRayFur

01. Introduction

VRayFur is an extremely useful, highly adaptable method of creating fur and hair in 3DS Max – it can even be used to make grass! This guide will explain all the settings used for this versatile object type and will use Terry Cloth as an example. Terry is a fabric with a surface covered with small loops of thread, and is used to make things such as towels or robes.

02. Common Parameters

a. Source object
Specifies the source geometry for the fur. You can click on this button only from the Modify panel (and not from the Create panel).

b. Length
Specifies the length of the fur strands.

c. Thickness
Specifies the thickness of the strands.

d. Gravity
Controls the force that pulls fur strands down along the Z-direction.

e. Bend
Controls the elasticity of the fur strands. When set to 0.0, the strands are hard and all straight lines. Greater values cause the strands to bend (e.g. under the influence of gravity).

f. Taper
Allows the user to add a taper to the individual strands of fur. Increasing this value will make each strand thinner in its upper end and wider in its base.

g. Knots
Fur strands are rendered as several connected straight segments; this parameter controls the number of segments.

h. Direction variation
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.

i. Length/Thickness/Gravity/Curl Var
Adds variation to the corresponding parameter. Values range from 0.0 (no variation) to 1.0.

j. Distribution
This section determines the density of strands over the source object.

i. Per Face
Specifies the number of fur strands per face of the source object. Every face will generate the specified number of fur strands.
ii. Per Area
Specifies the number of strands per squared scene unit. For example, if the system units are in meters, this parameter specifies the desired number of strands per square meter; if the system units are centimeters, it specifies the number of strands per square centimeter and so on. The area of the triangle faces (which is used to compute the number of strands for each face) is taken at the frame specified by the Ref. frame parameter. Every triangle face has at least one strand.

k. Curl
When enabled, adds curls to the fur.

l. Curl Radius
The radius of the individual curl.

m. Curl Angle
The number of curls on a strand.

03. Useful Maps

We will go over how some of these maps influence V-Ray fur later in this section. However, notice that some of the maps are RGB and some are monochromatic. Bend direction and Initial direction use different colors to denote different bend vectors, while other monochromatic maps like length use black and white to determine areas of, for example, long fur and short fur. For more details on these maps, see Chaos Group’s documentation on the subject.

04. VrayMaterial vs. VRayHairMaterial & Textures with Fur

With fur, it’s better to use the V-Ray Hair material because it is specifically designed for rendering hair and fur.
This special material simulates how light pases through fur.

Notice how the fur on the LEFT appear flat since the light is unable to pass through it like it naturally would. The fur on the RIGHT is using the hair material with basic settings and it looks more natural.

To apply a material to VRayFur, select the fur and click the “Assign Material to Selection ()” button in the Material Editor – or just drag the noodle from the right side of the material directly onto the Fur object.

Textures can be applied to fur the same way you would apply them to a model. The texture will display the same way as the model it’s attached to. So, if the UV’s aren’t right on the base object, then the texture will look stretched or completely wrong.

06. Thickness & Thickness Variation

05. Length & Length Variation

Determines the length of each individual strand of the fur. Length variation is important to prevent fake looking fur. Some situations require more variation than others.

07. Taper

Determines how thick the fur strands are as they reach the tip. On the left, there is no taper, so the fur’s
thickness is the same from the base to the tip. The left render has the same size base, but the tip tapers down to nothing.

08. Curl

In order to create realistic Terry, we need to use VRayFur with curl enabled. This will allow the strands to form loops. Two parameters control the curl: “Curl Radius”, and “Number of Curls”.

The transformation as “Curl Radius” increases.

The transformation as “Number of Curls” increases.

For Terry, keep the number of curls set to between 1 and 2. I’m going to use 1.3. The curl radius will decide how large each loop will be, so fluffier towels will have a greater curl radius value.

When curl is enabled, the length value represents the distance between the object’s surface and the end of each strand, not the total length of the strand. Therefore, setting the length value to 0” will create flat circles, rather than coils that have height.

Curls with the length set to a positive value.

Curls with the length set to 0”. (Same Radius and Number of Curls)

In this case, we want to set the length to a low number to add some fluff and dimension while still keeping the loops in tact. I have found that a length value that is double the curl radius works well.

09. Bend & Bend Variation

Determines how much the fur bends over after past the root of the strand. Fur with a consistent bend direction
doesn’t look good, so adding some variation helps.

Different RGB values cause the fur to bend in different directions. Here, we are going to use a bitmap of multicolored brush strokes in order to create natural variation across a furry ball . RGB to Vector image credit LightCollab.

The strength of of the bend direction map depends on the Bend value. A higher bend value will make the bend direction map more apparent. This shows what happens to Fur with a Bend Direction map as the bend Value increases and all other parameters remain constant. Notice how the hair gets “flatter” as it bends more due to the increased influence of the direction map.




Next, increasing the Direction variation can help break up the bend direction. Here, the direction variation value is increasing, while all other parameters remain constant. Even though there’s a bend direction map, the increased direction variation within that map is breaking up the patterns created by the map.

Direction var=.1

Direction var=.5

Direction var=.9

In addition to the Bend direction map, there is also the “Initial direction map”. For a terry cloth, we need loops instead of straight edges. An initial direction map work in the same way as a bend direction map – whereby a different color will point the fur in a different direction. RGB to Vector image credit LightCollab.

Here, a red vray color (RGB 255, 103, 103) is plugged into the Initial direction map. As the saturation increases from 0 to 255, the initial direction of each strand goes from perpendicular to tangent to the object’s surface.

The images below show the difference between initial direction and bend direction. Here, the same (red) vray color node is plugged into the initial direction map only (LEFT) and then the bend direction map only (RIGHT). Notice how on the left, the hair starts out at an angle but continues straight, whereas on the right the hairs start pointing straight out from the surface and then bend over near the midway point.

This is what curled fur looks like before and after adding the VRayColor shown above (RGB 255, 103, 103) as the Initial Direction map. All other parameters have been kept constant.

Curls with no Initial Direction map.

Curls with Initial Direction map (RGB 255, 103, 103)

Here are the vray fur settings have used so far in the previous examples applied to a stack of towels.

Next, we can add some subtle bend direction variation to fluff up the terry cloth.

Towels before and after adding variation to the fur

Here are our final V-Ray fur settings and the finished product! You can download the final model here.