What it checks

Checks read the object's own mesh, in every mode. A modifier that is not

applied is not part of the model yet and is left aside.

Using it

Everything lives in the viewport's Overlays popover, under Mesh Check.

1. Select the mesh objects to inspect and switch Check Data on. The

   selection is followed: select another object, it is checked; deselect

   it, it is dropped.

2. Switch Show Overlay on to draw the highlights.

3. Tick the checks you want. Each has its colour beside it.

The Faces Offset and Points Offset push the highlights a little

above the surface so they never fight the mesh for the same pixels.

Each checked object gets a collapsible block of statistics: vertices, faces

and triangles, then the count of every active check.

Seeing through the mesh

Show Hidden also draws the highlights hidden behind the mesh, through

it, fainter, so what is in front can still be told from what is hidden.

Alpha sets how faint. When the viewport itself is in X-ray, hidden

highlights are drawn this way regardless.

Very large meshes

A print-ready mesh is all triangles, and painting a million of them yellow

tells nothing that the number does not. Above the Draw Limit (100 000

by default, in the preferences), a check is still counted but not drawn:

the object's block shows a warning and the check reads (not drawn).

Preferences

Edit > Preferences > Extensions > Mesh Check GPU edition:

- Draw Limit, Show Hidden and Hidden Alpha, as above;

- edge width, face and edge opacity, the two offsets, vertex size;

- one colour per check.