Hard Surface Preservation
Organic meshes (scans, sculpts) can be crushed freely. Hard-surface and CAD parts cannot. Holes must stay round, panel lines must stay straight, and material borders must stay where they are.
The Preserve options keep those lines exactly in place while everything else gets crushed. They are all off by default.
The options
| Option | What it keeps in place |
|---|---|
| Borders | Open borders: holes and cut edges. They do not shrink or wobble. |
| Materials | The borders between materials. |
| UV Seams | UV seam lines, so textures do not smear across them. Needs Keep UVs. |
| Sharp Edges | Edges you marked Sharp, plus any edge sharper than Sharp Angle. |
Corner points of preserved edges never move. The crushed mesh also gets those sharp edges marked Sharp.
One-click setup
The Hard Surface button turns on all four options and sets Sharp Angle to 30°. Click it again to turn all four off. The button shows as pressed when all four are on.
You can also switch options on one at a time. For example, turn on only Materials to keep material borders on an organic mesh.
Sharp Edges and Sharp Angle
Sharp Edges uses two sources:
- Edges you marked Sharp in Blender.
- Edges where the two faces meet at more than Sharp Angle (default 30°).
Bumps from scan noise do not count as sharp. An edge over the angle only counts when it sits next to flat faces or bends one way, like a real crease.
On a mesh that reads as a scan (mostly noise, few flat faces), the angle test is skipped. Only the edges you marked Sharp are kept. The report names the objects where this happened. See Limits.
UV Seams
UV Seams needs Keep UVs to be on. If Keep UVs is off, the UV Seams button is greyed out.
Protecting more means fewer triangles removed
Every preserved edge is a line the crush cannot touch. The more you preserve, the fewer triangles can be removed. On low-poly parts with many creases, the result can stop above your target. The report then says that the preserve options kept N triangles and shows the target, so you can see how far off it is.
If that happens:
- Turn off the options you do not need.
- Raise Sharp Angle, so fewer edges count as sharp.
- Raise the target.
See Limits for the full list.
Presets
Presets remember the four Preserve options and Sharp Angle. Save one preset for hard-surface work and one for organic meshes.