Model repair in Cympha Studio: mesh tools overview and decision tree

This model repair overview matches each Cympha Studio mesh tool to the scan problem it fixes, with a typical repair order for the scans you attach to a dental case in Cympha.

Audience: Clinicians and lab designers new to Studio's mesh menu. You've added a scan and right-clicked it, you can see a list of commands (Fix model, Fill holes, Smooth, three brushes, Remove region (like attachment)…), and you want to know which one to reach for given the symptom you're looking at.

You'll come away knowing: how to open the mesh context menu, a one-sentence description of each tool's strength, a decision tree that maps symptoms to tools, and the canonical repair sequence to use when a scan needs more than a single pass.

Time required: Three minutes to read. The tools themselves take seconds to seconds-per-stroke once you've picked the right one.

Before you start

You need:

A mesh added to the scene — via the top-toolbar Add model (+), ☰ Open optical scan file…, drag-and-drop, or a URL. Formats: .stl, .ply, .obj.
No GuideMia case loaded. The standalone mesh cleanup commands appear on the right-click menu only for user-added meshes when no full .gvw case is open. If you have a case loaded, use ☰ → Clear scene first, or open the scan in a fresh Studio tab.
A desktop browser with a mouse. Some commands (notably Remove region (like attachment)…) are gated to wide layouts and won't appear on narrow / responsive viewports.

Sign into studio.cympha.com and open your mesh.

Step 1 — Open the mesh context menu

Right-click directly on the mesh body in the main 3D view. Right-clicking empty space won't open the menu — Studio needs a pick on the mesh itself. The menu title shows the file name, and the cleanup commands are listed right on this context menu.

The toolkit, one sentence each

| Tool | What it does, in one sentence | |---|---| | Fix model | Whole-mesh repair pipeline — duplicates merged, non-manifold geometry stripped, largest region kept, small holes filled, light global smooth. The "I just loaded an STL, give me a sane mesh" button. | | Fill holes | Whole-surface hole closing with a light global smooth. Same idea as Fix model but skips the destructive non-manifold passes. | | Smooth | Whole-surface Laplacian smooth — no topology changes, no triangle removal. Pure noise reduction across the entire mesh. | | Smart cleanup… | Brush mode — each stroke is auto-classified as delete (then hole-fill) or smooth based on how much of the painted region sits on an open boundary. The everyday targeted brush. | | Delete region… | Brush mode — every stroke removes the painted triangles and closes the resulting hole. Use when you want each stroke to cut, never smooth. | | Local smoothing… | Brush mode — always smooths the painted region, never deletes triangles. Safest brush when the defect is noise on anatomy you don't want to lose. | | Remove region (like attachment)… | Rectangle-drag mode — replaces a compact raised region with a ruled patch, snaps the seam, fills, locally smooths. The "wipe an attachment footprint" button. Desktop / wide layout only. | | Make dental model | Direction-arrow + dialog — extrudes the open boundary of a thin shell scan along an arrow toward a cut plane, producing a closed solid (a dental base). See How to build a solid dental model from a scan. |

Decision tree — match the symptom to the tool

"I just loaded the scan and want a single sane cleanup pass."
→ Fix model. See How to repair a mesh with Fix model.

"The mesh has obvious open holes everywhere but otherwise looks fine."
→ Fill holes. See How to fill holes and smooth in Cympha Studio.

"The mesh is bumpy / stair-stepped / noisy all over but topologically clean."
→ Smooth. (Same doc as Fill holes.)

"There's one specific bump / noisy patch I can see and the rest is fine — I want a targeted edit."
→ One of the three brushes. See How to clean up meshes with the brush tools for the full decision among them. Short version:

Smart cleanup… — let Studio decide delete vs smooth.
Delete region… — always delete the painted triangles (and close the hole), never smooth.
Local smoothing… — never delete, only smooth.

"There's a compact bump that's clearly a residual attachment footprint, and I want it gone in one click."
→ Remove region (like attachment)… (desktop / wide layout only). See How to remove a region with Remove region.

"My scan is a thin shell — open underneath — and I need a closed solid (printable base, classroom-ready model)."
→ Make dental model. See How to build a solid dental model from a scan.

"I removed too much material on the last stroke."
→ Press <kbd>Ctrl</kbd>+<kbd>Z</kbd>. Mesh geometry edits keep exactly one step of undo — it restores the previous model geometry (and redo reapplies it). To go further back than one step, reimport the source file with Add model (+). Keeping a backup of the source .stl / .ply / .obj is the safety net.

The canonical repair sequence

For a fresh intraoral scan that has multiple symptoms — small holes, some noise, and one or two attachment footprints from a pre-debond scan — work in this order:

Fix model for a single global pass (manifold cleanup + small holes + mild smooth + drop floating islands).
Fill holes if any open boundaries survived the Fix model pass.
Brush touch-up (Smart cleanup…) for any specific noisy patch you can still see.
Remove region (like attachment)… per attachment footprint, one rectangle each.
Optional final Smooth if the whole surface still reads as a touch noisy after the targeted edits.

Save or export when you're happy with the result.

Why this order. Fix model is the cheapest pass per change-rate of result — it's one click and fixes the easy stuff. Targeted tools come after so you're only spending careful attention on what Fix model couldn't catch. Remove region sits late because the global passes can shift the surrounding surface, and you want the surrounding surface stable when you place the rectangle.

Choosing between whole-surface and targeted

The whole-surface commands (Fix model, Fill holes, Smooth) treat every triangle the same. They're fast, they're one-click, and they can't tell whether a spike is noise or anatomy.

The targeted tools (the three brushes, Remove region (like attachment)…) limit the edit to a screen region you draw or paint. They're slower per defect but they don't risk degrading anatomy outside the region.

Rule of thumb: start with the whole-surface pass that gets you 80% of the way there in one click, then add targeted edits only for the residual defects you can see by eye. Don't reach straight for the brushes on a fresh scan — you'll spend an order of magnitude more time than running Fix model once.

What success looks like

The mesh you loaded is now manifold, has its small holes closed, and is smooth enough for downstream registration / measurement / export.
Any compact residual defects (attachment footprints, stray bumps) have been removed without affecting the surrounding anatomy.
You haven't deleted any anatomy you wanted to keep — backup of the source file confirms this if you have any doubt.

Troubleshooting

The right-click menu doesn't show the cleanup commands. A GuideMia case is loaded. Use ☰ → Clear scene and right-click the mesh again.

Remove region (like attachment)… isn't there but everything else is. The layout is too narrow. Widen the browser window and right-click again.

I want to undo a stroke. Press <kbd>Ctrl</kbd>+<kbd>Z</kbd> — geometry edits keep exactly one step of undo. To go back further than one step, reimport the source file with Add model (+). Keep a backup of the original as the ultimate safety net.

Fix model dropped a piece of geometry I wanted. The largest-region step trims disconnected components. If the scan had a legitimate detached piece you wanted to keep, skip Fix model and reach for Fill holes plus brushes instead.

A whole-surface pass changed anatomy I cared about. Press <kbd>Ctrl</kbd>+<kbd>Z</kbd> to restore the previous geometry, or reimport, and use the brushes from the start — targeted tools only edit what you paint.