Slot Split

By the end of this page you'll know how to click strands to move them into a different material slot, create a new mesh, and swap it into the scene.

Creates: A mesh asset, not a mask. Use this when different parts need completely different shaders.

The Split / Merge toggle at the top switches between two directions. Split exports strands to another slot, and Merge combines multiple slots back into one submesh.

When masks won't work

Masks control effect strength within one material. But "this part only with transparent shader," "this part only with emission material" — when the shader itself must differ, masks can't handle it. Instead, you split the mesh into submesh units.

Procedure

1. Select object → Load — instantly colored by current slot layout (see legend top left)
2. Specify target slot by clicking a row in the scene legend or mesh card
3. In scene view, Ctrl + click strands to move — selected strands show in target slot color
4. If you moved wrong, Reset Moves or Reset Structure to undo
5. Review Apply Plan card for per-mesh save paths and badges
6. Apply — confirm dialog, save new mesh assets, swap scene SkinnedMeshRenderer

Preview auto-restarts after apply.

Add and delete slots

Button	Does
+ Add Slot	Create new slot and auto-set as target
×	Delete slot and merge into slot above

A [Structure Changed] badge appears when structure changes.

Refresh

Refresh re-reads only the currently loaded mesh, regardless of Hierarchy selection. You can click another object in the scene, then come back — your target won't change.

Two kinds of reset

Button	Reverts
Reset Moves	Strand moves only. Slot adds/deletes stay
Reset Structure	Slot adds/deletes back to Load time

Apply Plan

The card above Apply shows what will happen before you commit.

Badge	Meaning
Create new	Makes new mesh asset file
Unique path	Same name exists; creates with different name
Overwrite	Previously Mask Maker-made output updated keeping GUID

Overwrite only happens on Mask Maker-owned files

Only outputs with matching Mask Maker ownership mark and original GUID/local ID keep their GUID on update. External files · unmarked files · files with different origins are never overwritten.

GUID preservation means prefab and animation references don't break.

Abort or failure rolls back everything. No partial-apply state remains.

Duplicate materials for new slots

By default, new slots get the same material as the original slot — you manually swap to your material after apply.

With Duplicate materials for new slots on, each new slot gets its own material (_SplitN.mat). You can immediately change values.

What's preserved

Data	Status
Blend shapes	Preserved
Bone weights	Preserved
UV (all channels)	Preserved
Normal · Tangent	Preserved
Submesh assignment	Only this changes
GUID	Kept when updating owned output
Undo/Redo	Supported

Merge Mode

The reverse of Split. Combine multiple slots back into one submesh — when you realize you didn't need to split, or to reduce draw calls.

Procedure

1. At the top, pick Merge
2. Select object → Load
3. Pick 2 or more slots to merge — slot card checkboxes (base map thumbnails visible) or Ctrl + click in scene view
4. Choose Keep Material. The merged submesh will use this material; the rest leave only the renderer (material assets are not deleted). Default is the first-picked slot
5. Merge — the confirm dialog shows a summary (Slots N→M, Triangle count)

The selection count displays as {picked} / {total} slots selected (need 2 or more).

Warnings don't block execution

Warnings appear in two cases but don't prevent running — there are intentional use cases.

Warning	Meaning
Base maps differ	After merge, only the kept material's texture is used
Selected slots' UV areas overlap	On one texture they'll share the same region

What gets saved and how to undo

Item	Behavior
New mesh	Saved as *_merged.asset next to the original (scene-only meshes prompt for save location)
Original asset	Unchanged
Renderer	Swapped to new mesh; merged slots removed from material array
Other renderers using same mesh	Rebind together — never a partial update
Ctrl+Z	Mesh and material array revert together

If you abort or fail mid-apply, the whole thing rolls back — no partial state.

Locks if Split mode has unapplied changes

If you've moved strands or added/deleted slots in Split mode without Apply, you can't use Merge. Apply them first, or use Reset Moves / Reset Structure to clean up.

Scene view operation (Merge mode)

Operation	Result
Ctrl + click	Select / deselect that slot
Ctrl+Z / Ctrl+Y	Undo / Redo

The Keep Material slot is picked from the panel, not the scene. Selected slot cards get a keep badge.

Scene view operation (Split mode)

Operation	Result
Ctrl + click	Move strand to target slot / undo
Ctrl + drag	Toggle passing strands
Ctrl+Shift + drag	Box add-select
Ctrl+Shift+Alt + drag	Box deselect
Plain click	Select scene objects normally
Ctrl+Z / Ctrl+Y	Undo / Redo

For inner and backface strands, turn on Backface Mode.

→ Hotkeys