Flip Orientation reverses the direction of all selected lines: each line runs from its last vertex to its first one. The shape and position of the lines do not change. It works on lines objects only; to fix inverted normals of a mesh, use Flip Normals.
Flip the Direction
- Select one or more lines objects in the Scene tree.
- Click Lines › Flip Orientation.
The command runs at once, without a panel, and nothing changes in the viewport, because only the order of the vertices is reversed. To undo it, press Ctrl+Z (Cmd+Z on macOS) or click Flip Orientation again.
When the Direction Matters
- Lines to Distance Map with the Contours orientation sign method decides which side of a closed contour is inside from the direction of the contour, so a reversed contour swaps inside and outside.
- Lines Derivative expects consistently oriented lines.
Check the Direction
Open Lines Info and switch Mode to Edge. VertId shows the start and end vertex of the edge, for example 15_v 16_v. After Flip Orientation the same edge shows 16_v 15_v: the direction is reversed. The Sym value stays the same.
The top line of the Lines Info panel tells you whether all edges of the object run in one direction (Topology is consistently oriented.). Flip Orientation reverses every edge at once, so it does not fix a line whose parts point in different directions.
