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Coding Passion

Grid and Snapping — Wall Plugin

Grid and Snapping

The plugin provides two snapping behaviors during wall placement: snap to grid and snap to wall.

Snap to Grid

When Snap to Grid is enabled in the Build Mode panel, all placement points are rounded to the nearest grid intersection.

SettingDefaultDescription
Snap to GridOffEnables the grid snapping behavior.
Grid Size100.0The grid cell size in cm. Minimum value: 1.0.

Grid snapping applies separately to the X, Y, and Z axes. Each coordinate is independently rounded to the nearest multiple of Grid Size.

Configuring from Blueprint or C++ (editor mode)

Grid snapping is configured via the editor mode class FEdModeCodPassionWall. It is not directly exposed to Blueprint as a subsystem setting — it is a property of the editor placement tool only.

Snap to Wall

When placing a wall (in the editor or at runtime) and the cursor crosses an existing wall actor, the cursor position automatically snaps to the bottom center of that wall at the nearest point.

This ensures wall endpoints connect cleanly without manually aligning coordinates.

The snap tolerance in the editor mode is hard-coded to 50.0 cm: if the cursor is within 50 cm of another wall’s surface, the endpoint snaps to that wall’s center.

Using snap-to-wall in your own runtime Blueprint

Call Convert To Bottom Center Position on the target wall:

HitWallActor -> Convert To Bottom Center Position
  Location:      (raw cursor hit location)
  Merge If Under: 50.0   ← snaps if within this distance of the wall's center
→ use result as the actual endpoint

Corner vertex joining

When two walls are connected via neighbor references, their shared vertices are recalculated so the meshes meet without a visible seam. This is not the same as snapping — it is a full geometry recalculation.

The connection works at any angle between the walls and with three or more walls meeting at a single point.

See Quick Start – Connect two walls for the step-by-step setup.

Merge Distance (painting)

The MergeDistance setting in the Paint Wall panel is a separate snapping concept for paint operations, not for wall placement. It snaps paint region boundaries to nearby wall endpoints or crossing nodes when painting.

See Materials and Wall Paint for details.