How to remove a region with Remove region in Cympha Studio

Remove region deletes a marked rectangle of stray geometry or an attachment bump and fills it with clean surface in one action, a quick fix for scans in a dental case in Cympha.

Audience: Clinicians and lab designers who need to wipe out a compact, well-defined region of a mesh — a residual attachment bump on a post-treatment scan, a printed bracket footprint that's still visible on a model, a small lump of stray geometry, or a localised scan defect — and replace it with a clean surface in one action, without painting brush strokes.

You'll come away knowing: when Remove region (like attachment)… is the right tool, how to invoke it from the mesh right-click menu, how the rectangular drag-selection works, the typical attachment-removal workflow on a post-treatment scan, and what happens at the edges of the selection.

Time required: Seconds per region. A full arch's worth of attachments goes quickly once you've done the first one.

Before you start

You need:

A mesh already 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. Remove region (like attachment)… appears on the right-click menu of a user-added mesh only when no full .gvw case is open. If you have a case loaded and want to clean a separate scan, use ☰ → Clear scene first.
A desktop / wide layout. Remove region (like attachment)… is hidden on narrow / responsive viewports — Studio only shows it when the browser is wide enough for the rectangular drag-selection to work reliably. If you don't see it on the right-click menu, widen the browser window (or rotate a tablet to landscape) and right-click again.
A backup of the original file. The region replacement is applied immediately. <kbd>Ctrl</kbd>+<kbd>Z</kbd> restores the previous geometry, but it's a one-step undo — if you notice the problem after a further edit, the recovery is reimporting the source mesh.

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

Remove region vs the brushes. Use Remove region (like attachment)… when the defect is a compact raised bump with a clean surrounding surface — the classic case is an attachment footprint. Use the brushes (Smart cleanup, Delete region, Local smoothing) when the defect is fuzzy noise or when you want to paint along an irregular shape.

Step 1 — Open the mesh context menu

Right-click directly on the mesh body in the main 3D view. The menu title shows the file name.
Find Remove region (like attachment)… among the cleanup commands on the context menu. If it isn't there, see "Before you start" — most often the browser is too narrow, or a GuideMia case is loaded.

Step 2 — Confirm the Create dialog

Click Remove region (like attachment)…. Studio opens a small Create / Cancel dialog:

It explains what the tool will do — replace the selected region with a clean surface blended into the surrounding mesh.
The region replacement is local — it doesn't repair manifold issues elsewhere, so you may still want a whole-mesh Fix model pass afterwards.
Click Create to arm the rectangle tool. Click Cancel to back out — nothing has been changed yet at this point.

Why the dialog exists. Remove region is more destructive in a small area than the brushes are — it doesn't try to decide between delete and smooth, it just replaces the selected region wholesale. The dialog is the moment to bail if you opened the tool by mistake.

Step 3 — Drag a rectangle around the defect

With the tool armed, your cursor enters a rectangle-selection mode on the 3D view.

Left-press with the cursor on the mesh (not on empty space). The first click must land on the model — that's what lets Studio still rotate the view from a press on the background, so you can frame the defect with your camera before arming or even mid-tool.
Drag to extend the rectangle around the bump.
Release the left button to apply. Studio computes the replacement and updates the mesh in place.

You only need to enclose the bump itself — give the rectangle a little margin around the obvious footprint, but don't drag a huge box "to be safe": the larger you draw it, the more surrounding anatomy gets rebuilt or blended.

Work on the side you can see. Rotate the view so the side with the defect faces the camera before you drag — the tool operates on the surface in front of you, not on geometry hidden behind it.

Step 4 — Inspect the result

After release:

The selected region is replaced with a smooth patch.
The patch is blended into the surrounding mesh so there's no visible step at the boundary.
The area around the patch is locally smoothed so the join isn't sharp.

Orbit around the result to confirm the bump is gone and the surface flows naturally into the surrounding anatomy. If you need to nudge a small surviving artefact, switch to Local smoothing… (see How to clean up meshes with the brush tools) for a non-destructive touch-up.

Typical attachment-removal workflow

For a post-treatment scan that still shows attachment footprints (the scan was taken before attachment removal in the operatory, or it's a model that was printed before debonding):

Add the scan with Add model (+).
Orbit so the buccal surface of the tooth with the first attachment is facing the camera.
Right-click the mesh → Remove region (like attachment)… → Create.
Left-drag a rectangle around the attachment footprint, just larger than the visible bump.
Release; confirm the surface is clean.
Rotate to the next attachment and repeat. The menu has to be reopened per attachment — this is intentional, so you can pause and inspect between sites.
Once all attachments are gone, optionally run Fix model on the whole mesh to catch any tiny manifold issues left behind.
Save or export.

What success looks like

The bump is gone and the area where it sat now reads as continuous tooth surface.
The patch joins the surrounding mesh without a visible seam or step.
The transition band has been gently smoothed — the boundary is invisible at normal viewing distance.
No back-of-tooth geometry was affected.

Troubleshooting

Remove region (like attachment)… isn't on the right-click menu. You're on a narrow / responsive layout, or a GuideMia case is loaded. Widen the browser and right-click again, or use ☰ → Clear scene to unload the case.

The rectangle didn't start when I pressed. The first press has to land on the mesh body, not on empty background — Studio reserves empty-space presses for camera rotation. Press directly on the visible surface of the model and drag from there.

The replaced area looks flatter than I wanted. The replacement patch is smooth by design, not anatomical. Draw the rectangle smaller next time so less real anatomy ends up inside the replaced area.

My rectangle crossed an existing hole and the patch looks strange. Remove region works best on a closed surrounding surface. If the rectangle straddles an open boundary, the patch may not blend cleanly. Close the hole first with global Fill holes (see How to fill holes and smooth in Cympha Studio), then run Remove region on the bump.

I removed the wrong area. Press <kbd>Ctrl</kbd>+<kbd>Z</kbd> — geometry edits keep exactly one step of undo, restoring the mesh as it was before the replacement. If you've edited again since, reimport the original file with Add model (+) and start over.

A second attachment didn't trigger the rectangle. Each region replacement is one rectangle, then the tool exits. Right-click the mesh again and pick Remove region (like attachment)… again for the next site.

The patch left a small stray island near the seam. Run Fix model afterwards (see How to repair a mesh with Fix model) — its largest-region step will drop disconnected fragments.