Hair Deformers

Think of them as nodes inside Hair System modifier. They give you ability change chair look: add noise, curls, snap to surface etc.
Deformers are stacked on top of each other, just like Blender modifiers.

Note: Some deformers (e.g. clump, twist, braids) will only work, if Hair System (to which deformer belongs to) is Set as Child

Note: Most of the input properties of Deformers can be masked by input masks like: vertex group, texture, length mask etc.

Animation

Attach Curves UV

Attach strands roots to source mesh UVs. Without it hair won't follow animated mesh ('Surface Deform' modifier will not work).

Bake/Cache Hair

Save hair strands into cached memory. They will no longer be editable, but will be faster to animate, since they will not be re-generated on every frame change.

Surface Deform

Same as blender built-in modifier. Allows hair to follow source mesh deformation (by rig or shape keys).

Note: You may want to use Bake deformer first, so that strands will not be regenerated on every frame

Physics

You can add collision objects, control: wind, gravity, damping etc. Not perfect yet, but can give some nice results. For more advanced physics simulation we may need to wait for native blender geo-nodes physics integration.

Note: You may want to use Bake deformer first, so that strands will not be regenerated on every frame

Note: If you notice some jittering, try reducing gravity and increasing damping.

For now self collisions are disabled, since you would have to subdivide strands a lot, to get good results. Long hair simulation may not look the best. But at least new HTool 4.x physics does not exploade like it used to in HT 3.x

Assign Group ID

Assign Group ID attribute to strands. After baking hair system you can use this to select strands by group ID.

Braids (Child)

Clump child strands to Guide/Parent strands (FIRST tag) in shape of Braids. Set Hair System as child first

Color Set (System)

It will allow your to colorize haircards material with generated SystemColor attribute. You can enable `Use HSV sliders' and combine them with Input Masks to create some nice effects

Clumps (Child)

Clumps child strands toward parent strands. Set Hair System as child first

Curls

We add curls effect to second Hair System and play with the: Frequency and Phase. The amount of curls (and clumps) is determined by parent strand count. Child-parent setup is needed

Delete Strands

Remove strands based on input mask. In video above I used Randomize input mask to remove some % of hair

Generators

Duplicate Strands

Simple duplication of existing strands

Braid Generator

Each strand will be duplicated 2 times (3 strands with original one), and braided together. Works best with 'Circular' Profile

The Idea in above video is:

  • Take single strand, and convert it to 3 braided ones with 'Braid Generator'
  • Duplicate each sub-strand few times with Duplicate Strands deformer
  • Add some randomization with Noise deformer and UV Region Distribute deformer

This should make it more volumetric looking, since braid will be made from multiple textured haircards, rather than single one.

Instance on Strand

Instance any mesh on hair Strands (can be used to eg. add tie and tail on the end of braid) - since HTool 2.44

Mirror

Mirror hair, with optional option of bisect (remove one half of hair first, then mirror the remaining part)

Move in/out of Surface

Embed Roots

Helps to push hair roots into surface. Best to used before Align Tilt deformer, since it can lead to haircard twisting

Push Out

Pushes hair strands away from the surface. Use to preventing clipping through character geometr or adding volume for layered hair styles

Attach To Surface

Attach hair to surface. Useful when wanting to 'glue' hair roots to character geometry (scalp)

Move to Border

In the video above, a source mesh is created using two half-sphere meshes. We use the "Move to Border" deformer to move the strands to the edge of this mesh. Then, we apply the 'Track To Mesh' deformer, to clump tips of strands together

Note: Often I like to move hair to border but only for strands that are within certain distance to the border. This can be done by using Border Edge Distance input mask. This way we can keep some strands in the middle of the scalp, while moving others to the border.

Snap

Snap hair to source surface (could be used for wet hair effect)

Lengthen

Lenghtens hair strands. Unlike simple scale - it will make hair extend from the tips

Noise

Adding Uniofomr noise, to break up the straightness of the strands and then bit of 'Per Strands' noise to add some randomness to the strands

  • Global Scale - Scales overall noise effect. Default value 1.0 is good for default cube (2 meters in size). For human head (which is around 1/10th of its size) set it to 0.1
  • Uniform Noise - it will give overall flow to the hair, breaking up the straightness of the strands.
  • Per Strands Noise - this will apply unique noise to each strand, giving it a more messy look.
  • Frequency - controls the detail of the noise. If set too high, it will make hair look 'bumpy' and unnatural.
  • Influence Range - Blend between original (straight) strand and the noise effect.
  • Flatten along Normal - it will remove the normal component of the noise, making it look more like than a 'wave'.

Note: Higher values of noise can push hair into the character head. To prevent this, use Push Out deformer after the noise deformer.

Radius Set

Set Radius - for hair tapering, strand width randomization, etc. Can also guide Curls amplitude or Braid size - for child Hair Systems

Roll Strands

Basically the same as blender build-in Roll

Scale

Scale hair up or down. With trim deformer we can reduce length of hair, but Scale deformer helps to make them longer.

Simplify Strands

Resamples strands - assigning lower points count to shorter strands

Slide Points

Give more resolution to hair root or tips (depending on 'Influence Range'), by 'sliding' points along the curves

Smooth Strands

Smooth out the strands

Tag

Assign Tag

Here we assign R tag to right side of head (masking it with vertex group). Then in 'Scale' Hair System that is set to Strands Filter we resize these tagged strands with Scale deformer

Note: Assigning any tag e.g. X will create negative tag 'X, for example if we create tag RIGHT with some strands, then tag 'RIGHT will contain opposite set of strands.

Delete Tagged Strands

Simple delete strands operation based on their Tag. In video above I removed strands tagged as R then GUIDE strands (bit hard too see, since they are covered by other strands)

Tilt

Add Tilt

Add tilt to hair strands. If 'Flip Probability' is 0.5 - then half strands will be rotated clockwise and half counter clockwise

Align Tilt

Aligns tilt to hair source surface (hair normal will point outside of surface)

Align Tilt to Parent

Aligns tilt to Parent (Guide) strands. Hair card backfaces are shown in blue. Great for Dragon Ball hairstyle :)

Align Tilt to Target

Aligns tilt to target surface (hair normal will point outside of target surface)

Align Tilt to Mesh Border

Align strands tilt to border of source surface (usually scalp). Backfaces are shown in blue

Force Align if checked, it will align curve and force curve normal to point outside border edge. If unchecked, tilt will be aligned to border, but curve normal will point with the 'flow' - see video above.

Track To:

It 'glues' hair tips to tracked (target) curve. You have control over tracking shape (straight or curved) and count of sampled points.

Track to Mesh

'Glue' hair tips, to target mesh object. If Separate Target per Island is enabled then only strands from the nearest mesh island (based on target origin location) will be affected (see video below)

With Separate Target per Island strands from one (closest) island will follow the guide. To prevent hair tips from 'sliding' use Bind Track Mesh button

In deformer settings you have control over shape of 'glued' curves - they can go straight or bent toward the target mesh.

Note: Closest active/affected island is determined by Tracked object origin. Move it to change 'active' island.

Note: It is good idea to create 'bind' shape-key, just after 'Bind Track Mesh' is pressed, on tracked mesh, and then work on extra 'Deform' shape-key. This way you can restore original 'bind' shape, re-run the 'Bind' and then switch back to 'Deform' shape-key.

Track to Curve

Similar to 'Track to Mesh', but it will 'glue' hair tips to target curve object.

Use Bind button to prevets hair tips from 'sliding' on tracked curve surface

Demo of 'Cornrows' feature with Track to Curve deformer. In this case the 'Samples Count' parameter defines density of 'cornrows'

Note: Closest active/affected island is determined by Tracked object origin. Move it to change 'active' island.

Note: Hair Tool Curve Shape Keys can be used to switch between 'bind' and 'deform' shape. This way you can work on non-destructive way, and restore original 'bind' shape at any time.

Second example of making 'Cornrows' hairstyle with Track to Curve deformer

Trim

It will shorten strands roots and/or tips. Best to use with randomization mask

Twist

Twist effect requires to set Hair System to be set as child. For best effect is is good idea to place it after Clump deformer

Profile Distribute

Mesh Profile or Multi Curve Profile holds profile objects list for instancing on strands, but it does not tell which strand will receive which profile object. This is where 'Profile Distribute' deformer comes in.

It will tell which strand will receive which profile object, based 'Profile_ID' attribute, assigned to each strand.

You can use multiple 'Profile Distribute' Deformers, and stack them on top of each other (think of them as layers). In video above, I used RED and GREEN profile objects as base layer, then added PURPLE on top - masked by vertex group

UV Region Distribute

Hair Profile holds UV Boxes/Regions amount and dimensions, but it does not tell which strand will receive which UV Region. This is where 'UV Region Distribute' deformer comes in - it will assign random (or masked) UV Region to each strand.

Note: use multiple 'UV Region Distribute' deformers + Input Masks, to achieve layered UVs effect (see video below),

Example use of multiple 'UV Regions Distribute' Deformers, to stack them on top of each other (as layers). Region ID_2 as base layer + Region ID_0 on top - masked by vertex group

Note: UV Region Distribute is often created automatically when hair system is added