Hair_Make_Hair - Diffeomorphic/import_daz GitHub Wiki

Make Hair

This is the main tool for converting mesh hair to hair curves. The same tool works for sheet hair, polyline hair, and strand-based hair. For documentation on converting mesh hair to particle hair relevant to Blender 3.x and before, see Make Particle Hair.

With the human selected and her hair active, press Make Hair. Since it can be difficult to remember which mesh to select first, the hair and human meshes are listed below the button, so we can easily detect if the meshes have been selected in the wrong order. Here we intend to let the hair grow on the scalp mesh, but we could have chosen to grow it directly on the head instead.

The options are arranged in four groups.

Create:

• Mesh Hair Strand Type:
  • Sheet: Use for sheet hair
  • Line: Use for polyline hair
  • Tube: Use for tesselated SBH. Can also be used for some sheet hair.
• Output:
  • Hair Curves: The hair systems based on geometry nodes. Not yet implemented and not available in Blender 3.4.
  • Particles: The old-style particle hair.
  • Curves: Ordinary curves.
  • Polylines: Line meshes, one for each strand.
  • Mesh: Single line mesh.
• Single Output: Hair output is a single object.
• Strand Orientation: How the strands are oriented in UV space.
  • Top-Down: Vertically with roots at top and tips at the bottom. The default and absolutely most common.
  • Bottom-Up: Vertically with roots at bottom and tips at the top.
  • Left-Right: Horizontally with roots to the left and tips to the right.
  • Right-Left: Horizontally with roots to the right and tips to the left.
• Separate Loose Parts: Separate hair mesh into loose parts before doing the conversion. Usually improves performance but can stall for large meshes.
• Check Strips: Check that the hair mesh consists of strips in UV space. Typically this gives an error if you have forgotten to separate the scalp.
• Keep Mesh Hair: Keep (reconstruct) mesh hair after making particle hair.
• Remove Particle Hair: Remove existing particle systems from this mesh.
• Sparsity: Ignore some hairs if this number exceeds one.

NOTE ON STRAND ORIENTATION. by Alessandro

The strand orientation is important because it allows to define how the strands flow in the hairstyle. The addon uses the uv map to reference the strands. We can select the strands in the uv map to see which orientation is used, for example a top-down orientation will have the strands from the top to the bottom.

In some cases different orientations may be used in the same hair style so we have to separate the hair by orientation before conversion. If this is not practical to do because the hair is particularly complex then the hair conversion can't be done correctly.

Material:

• Multi Materials: Create different particle systems for each material of the original mesh.
• Keep Material: Keep the existing materials. Mainly for polyline and strand-based hair, where hair materials are created when the meshes are imported.
• Material To Keep: If we create hair with a single material, choose which of the original materials to keep.
• Hair Material Method: Method used to create the hair materials, further described in the page on Material Methods.
  • Hair BSDF: Node tree with the Hair BSDF node (Cycles only).
  • Hair Principled: Node tree with the Hair Principled node (Cycles only, Blender 2.8x and later only).
  • Principled: Node tree with a principled node (Eevee and Cycles).
• Hair Colors: The colors of the particle hair.After a slight delay Aiko has particle hair, and the mesh hair can be hidden or deleted.

Settings:

The plugin attemps to add two geometry node modifiers to the hair curves, Set Hair Curve Profile and Duplicate Hair Curves. The settings refer to parameters of these modifiers. If the geometry node trees are not present in the blend file, the settings have no effect.

• Render Children: The number of hair children displayed in renders.
• Viewport Factor: The fraction of children displayed in the viewport.
• Child Radius (mm): Radius of children around parent.
• Hair Radius (mm): Radius of the individual strands.
• Strand Shape:
  • Standard: Standard strand shape.
  • Fading Roots: Root transparency (standard shape with fading roots).
  • Root And Tip Shrink:

Here the hair curves with modifiers. If the modifiers are not added automatically, they can be added from the asset browser.

The Fading Roots option adds a node group to the hair materials, just before the outputs.

The node group adds transparency to the strand roots.

Deform

• Parent to Head: Since hair curves don’t have vertex groups, they are bone parented to the head bone by default. This makes sense for hair but not for fur.
• Hair Proxy: Create a proxy mesh which deforms the hair curves. The parent to head option affects the proxy mesh as well.
• Surface Deform: Add a surface deform modifier to the proxy mesh.
• Hair Simulation: Add a cloth simulation to the proxy mesh. The simulation is done on top of the surface deform.
• Proxy Mesh: The type of the hair proxy mesh.
  • Line: Line proxy mesh.
  • Sheet: Sheet proxy mesh.
  • Tube: Tube proxy mesh.
• Copy Vertex Groups: Copy vertex groups from the original hair mesh to the hair proxy.

If Hair Proxy is enabled, a proxy mesh is created.

It has a vertex group that determines the distance along the strands from the roots.

A modifier is added to the hair curves that makes them follow the proxy. This modifier is first in the modifier stack.

If the Surface Deform option is enabled, a surface deform modifier is added to the hair proxy. It is place above the cloth modifier responsible for simulation.

If the Hair Simulation option is enabled, new option appear.

• Proxy width (mm): Width of the proxy strands.
• Pinning Group: Add a pinning group to the hair proxy.
• Mapping curve: The weights of the pinning group, from root to tip.
• Cloth Simulation: Add a cloth simulation to the hair proxy.
• Collision Collection: Cloth preset.

A cloth simulation is now added to proxy mesh, which also affects the hair curves due to the follow proxy modifier.

Tip: The cloth modifier can slow down the viewport a lot, because Blender has to recalculation the simulation. It is therefore a good idea to put the hair curves and the proxy mesh in a separate collection, which can be disabled during posing.

For an example of hair simulation, see the post on Hair Simulation.

Polyline Hair

The Make Hair tool can also be used for polyline hair. The workflow is the same, except that the Mesh Hair Strand Type must be set to Line. The tool automatically detects the strand type.

Here is the Mohawk hairdo converted to particle hair.

Strand-Based Hair

The Make Hair tool also works for tesselated SBH. In this case the Strand Type must be set to Tube, which is also done automatically.

Below the tesselated SBM is converted to particles and rendered.