Hair Property Editor

Controls the basic parameters of a hair object, affecting mostly the render hairs. However, the parameters on the Dynamics page affect guide hairs.

To apply: Choose Create Hair from Selection or Create Hair from Curves on the Hair toolbar.

To redisplay: Select the hair object, click the Selection button on the Select panel, then click the Hair icon.

For more information in general about hair, see Hair and Fur Basics.

General

Display Settings

Controls how hair is displayed in the 3D views.

For more information, see Viewing the Hairs.

Display Type

Controls whether guide hairs or render hairs are displayed in the 3D views:

Guide Hairs displays the curves between which the render hairs are interpolated. This option provides the fastest display and interaction.
Render Hairs displays a percentage of the render hairs. This option gives a better approximation of the final result, but may be slower especially with a large number of hairs.
Use Display Mode displays differently depending on the display mode of each viewport. The hair object's bounding box is displayed in Bounding Box mode, the guide curves are displayed in Wireframe, Depth Cue, and Hidden Line Removal modes, and render hairs are displayed in Constant, Shaded, Textured, Textured Decal, and Realtime Shaders modes.

Note that guide curves are always displayed when the hair object is selected or active for component selection.

Render Hairs %

The number of hairs to display when render hairs are visible. This is a percentage of Total Hairs under Render Settings below. Increase this value to get a better approximation of the final result, or decrease it to get faster display and interaction.

Render Settings

Render Hairs %

The number of hairs to draw when rendering. This is a percentage of Total Hairs below. Typically you would use 100 for the final render, but you can decrease this value to get a rough idea of the final result for quick render tests.

Total Hairs

The total number of hairs in the hair object. If you use a Density Map to remove a proportion of hairs in some regions, then the actual number of hairs will be less than this value. In addition, you can add extra hairs using the Hair Multiplicity options.

You can adjust the number of hairs that are displayed using Render Hairs % under Display Settings above, and adjust the number of hairs that are rendered to file or in the render region using Render Hairs % under Render Settings.

Hair Geometry

Sets up the BSP tree for rendering hair geometry. Hair is rendered as a special hair primitive by the mental ray renderer.

For more information, see Setting Up for Rendering Hair.

Maximum Depth	Maximum number of branches down the tree until it stops splitting into more branches. Range is 1 to 64.
Maximum Size	Maximum number of hairs each leaf on the tree can hold before converting that leaf into a branch to allow for further splitting. Range is 1 to 80.

Hair Multiplicity

For more information, see Increasing the Number of Render Hairs.

Strand multiplier	Copies every hair strand by the specified number. Note that you must set a non-zero Splay value or the duplicated strands will be completely coincident.
Strand type	The method used to determine the area in which the hairs are splayed: Proportional (the default) determines the amount of splaying relative to the length of the hair. The shorter the hair, the smaller the area in which the duplicated hairs are splayed. Absolute sets the hair splaying to the absolute values set for the Splay at tip and Splay at Root parameters.
Splay at tip	Splay at tip offsets the new hairs (based on the value set for Strand multiplier) starting from the tip, creating the effect of sprouts — or hair plugs! The higher the value, the farther from the original hair the copies are splayed.
Splay at root	Splay at root offsets the new hairs (based on the value set for Strand multiplier) around the root area of the original render hair strand. The higher the value, the farther from the original hair the copies are splayed.

Hair Generation

Allow Stretching of Hair Segments

Activates Stretchy mode (see Stretching Hair Segments [ Hair ]), in which the guide hair segments can have their length changed (hair segments are normally fixed in length). When you style or animate hair in stretchy mode, the hair strands behave more like curves than an IK chain with fixed segment lengths.

Hair segments

The number of subdivisions along the length of the render hairs. Higher values produce smoother hairs but require longer processing times.

For more information, see Changing the Length of Render Hairs [ Hair ].

Render quality

Sets the quality of the rendered hair to low, which is faster but of lower quality, or high, which is better quality but slower.

Hair Collision

For more information, see Setting Up Hair Collisions.

Collision type

Sets the type of collision the hair has with objects set as obstacles.

Average Sphere creates a sphere around the obstacle object for the collision detection, giving fast calculations. This option disregards the settings in the Obstacle property editor.
Exact uses the actual shape of the obstacle object for the collision detection, which is desirable in most cases. This gives accurate results but may have a slower calculation time. This option disregards the settings in the Obstacle property editor.
XSI uses the settings in the Obstacle property editor as a basis for the collision detection. For example, if you have Actual Shape set as the Obstacle Type, the actual shape of the obstacle object is used in the calculations. This makes for a fairly fast calculation using whatever settings you have.

NoteThe Friction and Elasticity parameters in the Obstacle property editor are not used in the calculation of hair collisions.

Effects

The parameters on this page affect only the render hairs. They have no effect on the guide hairs.

For more information, see Frizzing Out.

Frizz

Displaces each vertex in every strand according to a noise rotation, resulting in hair frizziness or static. It is relative to the length of the strand (before any Cut Map is taken into consideration) so that for the same value, vertices on shorter strands are displaced by smaller amounts.

Frizz at root	Adds a noisy rotation of the hair strands starting from their bases. This value sets the total rotational offset, and is scaled by three level 3 harmonic noise fields whose frequency is set by the Frequency. If Frizz at root is relatively high and Frizz at tip is relatively low, the effect is like using mousse to scrunch together hair at the tips while preserving the chaos at the roots.
Frizz at tip	Adds a noisy rotation of the hair strands starting from their tips. This value sets the total rotational offset, and is scaled by three level 3 harmonic noise fields whose frequency is set by the Frequency. The visual effect is frizziness.
Frequency	The frequency of the frizz noise pattern along the X, Y, and Z axes. This value is relative to the size of the hair-emitting element so that, for example, small objects are not relatively frizzier than large objects. In other words, the same value produces the same number of "bends" on small objects as on large objects. Link XYZ axes allows you to change all XYZ values to the same value by changing one.
Frizz Animation	Allows you to animate the frizz parameters for extra hair motion. You can use this in place of the Wiggle parameters for creating certain effects, such as wavy grass.
Frizz anim	Controls the amount that the frizz is animated (similar to Wiggle Amplitude).
Anim speed	Controls how quickly the frizz is animated (similar to Wiggle Speed).
Direction	Sets the direction of the frizz animation along the X, Y, and Z axes.

Kink

Displaces each vertex in every strand according to a noise pattern. The visual effect is kinkiness or waviness. It is relative to the length of the strand (before any Cut Map is taken into consideration) so that for the same value, vertices on shorter strands are displaced by smaller amounts.

Kink at root

Adds noise to the hair strands starting from their bases. This value sets the total offset, and is scaled by three level 3 harmonic noise fields whose frequency is set by the Frequency.

If Kink at root is relatively high and Kink at tip is relatively low, the effect is like using mousse to scrunch together hair at the tips while preserving the chaos at the roots.

Kink at tip

Adds noise to the hair strands starting from their tips. This value sets the total offset, and is scaled by three level 3 harmonic noise fields whose frequency is set by the Frequency.

Frequency

The frequency of the Kink noise pattern along the X, Y, and Z axes. This value is relative to the strand length (before any Cut Map is taken into consideration) so that for the same value, long and short strands have the same number of kinks.

Link XYZ axes allows you to change all XYZ values to the same value by changing one.

Thickness

For more information, see Setting the Render Hair Resolution (Segments).

Type	The method used to determine each render hair's thickness. Proportional (the default) determines the hair thickness relative to the size of the emitting area on the hair emitter's geometry. Basically, the larger the emitting area, the thicker (and longer) the render hairs. Absolute sets the hair thickness in an absolute size using the Root and Tip parameter values. The values are in 100ths of a Softimage unit. For example, a Root thickness value of 50 would make the roots 50/100 or 0.5 Softimage units in diameter.
Root	The size of the render hairs at their base.
Tip	The size of the render hairs at their tips. Depending on the thickness Type you select, the Root and Tip thickness values will have different results: With Proportional as the Type, the Root and Tip values are relative to the emitter size. For example, hair is thinner when emitted from a smaller area, so Root and Tip values at 1 would give different results than the same values for hair emitted from a larger area. With Absolute as the Type, the Root and Tips values are the actual diameter of the hair (at the root and tip, respectively) in 100ths of Softimage units.
Random scale	Applies a consistent random scale to the generated hair. The hairs are only scale down: the render hairs are never scaled to be larger than they are. A value of 1 is totally random, while a value of 0 changes nothing.
Cut Map	Allows you to connect a weight map or texture map to cut the length of the render hairs in different areas. At a value of 0, the render hairs are cut at the root. At a value of 1, render hairs follow the entire length of the guide curves. At values in-between, the render hairs follow a portion of the guide curves. See Cutting the Render Hairs [ Hair ] for more information.
Density Map	Allows you to connect a weight map or texture map to remove a proportion of hairs in different areas. The value of the map controls the probability of a hair being removed. Where it is 0, all hairs are removed; where it is 1, no hairs are removed. At values in-between, the corresponding proportion of hairs are removed. See Setting the Render Hair Thickness [ Hair ] for more information.

Instancing

Instancing allows you to replace hairs with any type of geometry during the rendering process. Create a group that includes the objects you want to use as instances, and each object in the group is assigned to the hairs during rendering. You can choose how the objects are assigned, as well as how they are oriented.

For information on instancing, see Rendering Objects (Instances) in Place of Hairs.

Enabled	Enables the rendering of the instanced geometry you define in the Instance group box instead of the hair geometry. When this option is off, the hair geometry is rendered as a special hair primitive by the mental ray renderer.
Instance group	Group of objects you have picked to replace the render hairs during rendering. Select one or more objects you want to instance and create a group that includes them.
Pick	Click this button, then in the explorer select the group of objects you have created to be instances.
Remove	Removes the current group of objects from being used as hair instances.
Instances on Guide Hairs	Applies the instances only to the guide hairs, but not to the render hairs. This is an easy way of having the instances appear only at the hair emitter's vertices.

Assignment

For information on using these options, see Selecting How Instances are Assigned.

Object Assignment

Select the method by which the instanced objects are assigned to the hair:

Random: Distributes the instances on the hair randomly, meaning that you can't control which instance object is assigned to which hairs.
Using Weight Map: Uses the values on a weight map to assign the instances to the hair. Where the weight map's values are 0, the object listed at the bottom of the instance group (in the explorer) is used; where the values are 1, the object listed at the top of the instance group is used.

Object Assignment Map

If you selected Using Weight Map as the Object Assignment, you must select the weight map to use for distributing the instances.

Fuzziness (%)

Using values from 0 to 100%, this option blends the values of the weight map so that the division between the instanced objects is less distinct.

Orientation

Allows you to control the orientation of the instanced geometry according to a tangent map or to the location of target objects.

For information on using these options, see Setting the Instances' Orientation.

Type	Select the method by which the instances are oriented: None: Instance orientation is not changed. Tangent Map: Instances are oriented according to a tangent map, which give each instance a local XYZ coordinate system based on the RGB values of the emitter's VertexColor property (tangent maps are stored in this property). Tangent maps orient the instance so that its X axis follows the U direction of the hair emitter. Follow Object: Instances are oriented according to the location of one or more target objects. You can use multiple objects for which the instances will pick a direction which is a weighted average by distance to each target object; that is, the target object closest to the hair has more of a "pull" than a target object that is farther away. For a single object, the instances always point toward that target.
Tangent Map	If you selected Tangent Map as the Type, you must select the tangent map to use for the orientation of the instances.
Target Group	If you selected Follow Object as the Type, you must select the group of one or more target objects whose location the instances will follow.
Spread	Rotates the instances locally in degrees (0 to 360). A distribution method is used to allow for some randomization of rotation values among the instances. Select Linear for a simple, linear distribution of the Spread value among the instances. Select Gaussian for a normalized distribution of the Spread value among the instances based on a bell-shaped curve.

Dynamics

The parameters on this page have an effect only when dynamics has been applied to the hair object. These parameters are applied to the guide hairs, but have a visible effect on the render hairs.

If you have animated parameters for certain styling operators (Clump, Comb, Puff, Rotate, and Scale), you cannot use dynamics on the hair.

For more information, see Making Hair Move with Dynamics.

Stiffness	The tendency of the hairs to hold their original, styled shape while under the effect of dynamics. This is the stiffness of the guide hair starting at the hair tips, with the effect lessening toward the root. A value of 1 means that hair will always keep its styled shape.
Root Stiffness	Same as Stiffness except it determines the stiffness at the root of each guide hair. The default value of 1 means that the guide hairs will always keep their styled shape at the root.
Wiggle	Simulates a light breeze by randomly displacing the vertices of guide hairs. Amplitude controls the size of the displacement. Speed controls the speed of displacement.
Dampening	Determines how quickly the hair recovers from the effect of dynamics. The default value is 0, but higher values (maximum value is 1) make the hair bounce back into its styled position more quickly.

Presets

Click a button to set the Frizz, Kink, and other parameters to preset values for different hair types. You can then tweak those parameters further if you wish on the Effects tab.

Note that these buttons do not affect the guide curves and you must still groom the guide curves to obtain the desired hair styling.