Blender

Hair from Blender

This page takes a hairstyle from Blender to Godot: the hair is groomed with Blender's hair tools, the character goes to Godot as a glTF file, and the hair as a .tfx (the strands) plus a .tfxbone (which bones each strand follows), plus .tfxmesh files for the collision shapes. The exporter, Blender to Godot Hair, ships with the addon as addons/tressfx/tools/tressfx_blender_export.py.

Requirements: Blender 4.2 or later (tested with 5.2) and Blender's own hair system, the Curves object. Older particle hair can be converted, see step 2.

A finished example ships with the addon: addons/tressfx/demo/blender_hair/source/blender_hair.blend holds a head with a spiked mohawk (one hair object) and two collider meshes (the head, the neck and shoulders), and addons/tressfx/demo/blender_hair.tscn is the same character in Godot. Open the .blend, change the hair, press Export to Godot and the demo picks up the new files.

1. Install the exporter

1. In Blender open Edit > Preferences > Add-ons.
2. Open the drop-down menu at the top right, choose Install from Disk and pick tressfx_blender_export.py.
3. Tick Blender to Godot Hair if it is not ticked already.

The add-on also has its own repository, Blender to Godot Hair, with release zips that install as a Blender extension.

The 3D Viewport's sidebar (press N) now has a TressFX tab, and File > Export has a TressFX Hair (.tfx) entry. To try the add-on without installing it, open the file in Blender's Text Editor and press Run Script; it stays until Blender is closed.

The TressFX tab follows the whole workflow in three boxes: 1. Hair shows what is selected and the next step (add hair, sculpt, pick the surface), 2. Colliders marks the meshes the hair must stay out of, 3. Export to Godot writes everything.

2. Groom the hair

Start from a character that is ready for Godot: a head mesh with a UV map and, if it is animated, either an Armature modifier with vertex groups (a skinned character) or a Bone parent (a character made of rigid parts). Blender works in metres, so does Godot; keep the scene's Unit Scale at 1.

1. Select the head mesh and press Add Hair to ... in the TressFX tab (or choose Add > Curves > Empty Hair). Blender creates a hair object whose surface is the head, switches to Sculpt Mode and picks the Add brush. The exporter reads UVs and bone weights from the surface; the tab shows it under Surface.
2. Sculpt the hair (the tab's Sculpt Hair button enters Sculpt Mode). The main brushes:
   • Add plants new curves where you click on the scalp. Set Curve Length and Count in the tool header before painting. Density adds or removes curves to reach a spacing.
   • Comb, Snake Hook and Puff shape the hair; Smooth removes kinks.
   • Grow / Shrink changes the length, Delete removes curves.
   • Turn on the collision toggle (the physics icon in the header) so combed hair stays above the scalp.
3. Keep an eye on the curve count (Overlays > Statistics). Every curve becomes a guide strand, and TressFXHair adds follow strands around each guide in Godot (num_follow_hairs). A few thousand guides with two or three follow strands each is a full head of hair. Short fur can use more guides with fewer vertices each.
4. Hair modifiers from the Add Modifier > Hair menu (Clump Hair Curves, Curl Hair Curves, Frizz Hair Curves, Braid Hair Curves, Trim Hair Curves and the rest) are baked into the export: the exporter reads the hair as you see it in the viewport. Interpolate Hair Curves and Duplicate Hair Curves work too, but they multiply the curve count; the follow strands do the same job for less.
5. Parts of a hairstyle that must move differently (bangs, a ponytail, a braid) belong in separate hair objects. Each one is exported to its own .tfx and becomes its own TressFXHair node with its own stiffness and gravity. To split a hair object, select the curves in Edit Mode and press P (Separate).

Particle hair from an older file. Select the mesh and press Convert Particle Hair in the TressFX tab. It converts the particle systems to hair objects, sets their surface and UV map, and hides the particle hair. (Blender's own Convert to Curves in the particle system menu leaves the surface empty; set it in the tab's Surface field.)

3. Mark the colliders

The hair needs something to stay out of: the head, the neck, the shoulders. In Godot a sphere or a capsule does the job (step 5), but you can also model the collision shape in Blender and export it with the hair.

1. Model a closed, low-poly mesh that sits just inside the skin, a few hundred to a few thousand faces. A copy of the body with a Decimate modifier and Shrink/Fatten applied is a quick start. Leave out the parts the hair never reaches.
2. Skin it like the character (an Armature modifier with the same vertex groups, Ctrl+P > With Automatic Weights, or a Data Transfer of the weights), or parent it to a bone.
3. Select it and tick ... keeps hair out in the 2. Colliders box. The mesh turns into a wireframe and is no longer rendered or put into the .glb.

The hair's rest pose must start outside the colliders: keep them a few millimetres under the scalp.

4. Export

In the 3. Export to Godot box:

1. Folder: a folder inside your Godot project. // means the folder of the .blend file.
2. Vertices: 8 for short fur, 16 for most hair, 32 for long or curly hair. Each curve is resampled to this many evenly spaced points.
3. Bone Weights: writes a .tfxbone next to each .tfx when the head is moved by an armature.
4. Colliders: writes every marked collider as <object name>.tfxmesh.
5. Character: also writes the scene as a .glb, named after the .blend unless you type a name. Colliders and other objects disabled for rendering are left out.
6. Press Export to Godot. Every visible hair object is written as <object name>.tfx; the box lists the files and the result of the last export.

To export the character yourself, use File > Export > glTF 2.0, keep +Y Up and turn on Apply Modifiers (Mesh section). The hair was placed on the head as Blender shows it, with its Subdivision and other modifiers; without them the head in Godot has a different shape and the hair floats. File > Export > TressFX Hair (.tfx) exports only the active hair object.

What the exporter writes:

• The strands in the character's rest pose. The armature is switched to Rest Position for the export and back afterwards, so you can export in the middle of an animation.
• Positions in Blender world space turned Y-up, the same space the glTF exporter uses, so hair and character line up in Godot without any offset.
• A root UV per strand, from the surface's UV map. The strand shader uses it to tint each strand with the colour of the skin under it (base_albedo).
• For each strand, the bone weights of the surface at the root, blended from the three nearest vertices and reduced to the four strongest bones. A root on vertices without any bone weight is bound to the nearest bone and reported in a warning. When the head hangs from a bone (a Bone parent, no Armature modifier), every strand follows that bone.
• Bone names as Godot's importer writes them: : and / become _, so Mixamo's mixamorig:Head is written as mixamorig_Head.
• For each collider, its triangles and vertices in the same space and rest pose, each vertex with the four strongest bones of its vertex groups (or the parent bone).

The status bar shows the strand and bone count, or a warning when something is missing.

5. Set it up in Godot

1. Add the imported character to your scene.

2. Add a TressFXHair node. Set tfx_path to the .tfx. Leave import_scale at 1.

3. Animated character: set tfxbone_path to the .tfxbone and hair_skeleton to the character's Skeleton3D. If the node picker does not list the skeleton, right-click the character in the Scene dock and enable Editable Children. The hair node can sit anywhere in the tree. Static character (a bust, a statue): leave both empty and make the hair node a child of the character with no offset of its own. The hair then follows the character's transform.

4. Give the node a material, as in Getting Started: a ShaderMaterial with addons/tressfx/shaders/tressfx_strand.gdshader. Put the character's albedo texture in base_albedo to colour the roots like the skin under them.

5. Set num_follow_hairs to 2 or 3.

6. Add the colliders and list them in the hair's collision_meshes:

   • From Blender: a TressFXCollisionMesh per .tfxmesh, with tfxmesh_path set. For an animated character also set its hair_skeleton (it can sit anywhere); for a static one make it a child of the character with no offset, like the hair.
   • Primitives: add a BoneAttachment3D next to the character, turn on Use External Skeleton, pick the skeleton and the head bone, and put a TressFXCollisionMesh with a SphereMesh under it, moved to the centre of the head. See Getting Started.

   The editor draws the colliders in orange; select the hair to see all of its colliders on top of the body. The Hair Colliders button in the 3D toolbar hides and shows them.

Then press play, or scrub an animation in the editor, and tune the look and the motion with Tuning.

Keep both programs open while you work: after Export to Godot, the Godot editor reimports the .glb, every TressFXHair reloads its .tfx and .tfxbone and every TressFXCollisionMesh its .tfxmesh within a second or two. A new hair object or collider needs its own node.

Troubleshooting

The hair floats next to the character or is rotated. The character was exported without Apply Modifiers or with +Y Up turned off, or it was moved in Blender after the hair was exported. Export both again with the Export to Godot button. For a static character, check that the hair node has no offset relative to the character.

Output: "bone 'X' from hair.tfxbone not found in the skeleton". A bone was renamed after the hair export, or the character comes from another file. Export the hair again from the file the character was exported from.

The hair does not follow the head. hair_skeleton or tfxbone_path is empty, or the export warned that there was no surface mesh: set Object Data Properties > Surface on the hair object and export again. Check that the surface mesh has vertex groups named after the bones.

The hair stands out from the head at the start. The colliders are larger than the head; see Troubleshooting.

Export says "has no curves". The hair object is empty: plant hair with the Add brush first.

File > Export says "Select a hair object". The active object is not a hair (Curves) object. Click the hair in the viewport or the Outliner first, or use the TressFX tab, which exports all hair objects at once. For particle hair, convert it as described in step 2.

The hair stands out or jumps at the start. Its rest pose is inside a collider. Select the hair in Godot: the orange shapes that cover strands are too big. Shrink the collider in Blender and export again.