Purge Unused
Remove unused materials while keeping materials needed by saved variants.
- Where to find it
- Main toolbar → Purge Unused
- Scope
- Model materials, including saved variant references
- What changes
- Removes eligible unused material definitions.
On this page
How to use it
- Choose UMM’s Purge Unused.
- Review which materials were removed and which variant materials were preserved.
Expected result
Discard an unused test finish while keeping walnut needed by an inactive kitchen variant.
Controls & options
| Control | What it does |
|---|---|
| Purge Unused | Run UMM’s variant-aware removal of unused materials. |
| Result | Review removals and the number of variant materials preserved. |
Saved variant protection
Imagine Natural Oak is applied while Dark Timber is saved as an alternative. The dark material may have no current model assignments, but the saved look still needs it. UMM reads saved variant references when deciding what cleanup may remove.
Protection covers references in saved sets and supported saved mapping data. It is not limited to the currently selected or applied variant.
Purge behavior
UMM’s Purge Unused preserves materials referenced by Material Variants even when they are not currently painted on geometry. Materials still assigned in hidden geometry or unused definitions also count as model references.
An apparently unused material remaining after cleanup can therefore be expected behavior. Review your saved choices before deciding it should be removed.
Related duplicate protection
UMM excludes variant-protected materials from duplicate replacements that would remove them. Two similar-looking materials may intentionally remain because a saved look or mapping refers to a particular material.
Merge Duplicates still handles eligible unprotected duplicates. A material with locked references can also be retained; the result explains what could not be removed.
Removing saved alternatives
Review the variants and families you no longer need, then remove their saved configuration deliberately. Removing a saved variant does not itself repaint the current model or guarantee that all its materials are now removable.
Other variants, saved mappings or actual assignments may still refer to those materials. Run UMM cleanup again and review the result.