Non-Planar Faces Overlay

Toggles a sticky viewport overlay that highlights every non-planar face of the active edit-mesh in real time. Fix a face — flatten it below the threshold — and its highlight disappears on the next redraw.

bl_idname: iops.mesh_nonplanar_overlay Mode: Edit Mesh Context: VIEW_3D Modal: no HUD: yes

What it does

• Checks every visible quad/ngon of the active object (triangles are always planar and skipped). A face is non-planar when any corner's plane deviates from the face's best-fit plane by more than the Non-Planar Angle threshold.
• Non-planar faces are filled with the theme's error color. Fill intensity scales with the deviation: faces just past the threshold are faint, faces warped 15° or more draw at full strength.
• A Non-Planar row in the iOps statistics overlay shows the current count while the mode is on — red when faces need fixing, green at 0 (which also confirms the mode is active when everything is planar).
• The overlay is sticky: it survives object switches and mode changes (it only draws in Edit Mode) and stays active until toggled off.

How to use

1. Enter Edit Mode on a mesh and run Non-Planar Faces Overlay (F3 search, or bind it to a hotkey).
2. Model. Highlights update live as you move vertices; deviation-heavy faces glow stronger.
3. Run the operator again to turn the overlay off.

Settings

• Preferences → Non-Planar Overlay → Non-Planar Angle — threshold in degrees (default 0.5°). Faces below it count as planar. The full-intensity ceiling (15°) is fixed.

Notes

• Only the active object is checked in multi-object edit sessions.
• Detection runs in world space, so non-uniform object scale is measured the way you see it.
• Hidden faces are ignored.