Swap normals (only Preprocessing)

Menu: Utilities->Swap normals

This command can be applied to lines or surfaces (in geometry mode) or to elements (in mesh mode). A selection is made (see Entity selection) and the orientation of the selected entities is inverted.

Viewing commands (zoom, rotation, etc.) can be applied and the normals will remain on the screen.

When this command is applied to surfaces or mesh elements, you can choose one of the following options:

• Select: Inverts the direction of the normals of the selected surfaces.
• Make coherent: Inverts the normals of all selected surfaces or elements so that all of them have their normal in the same direction as adjacent entities. This direction is arbitrary, but is common to all adjacent entities.
• Select by normal: You are prompted to enter a vector and all selected entities' normals are swapped so as to have their normal in the same direction (dot product positive) as the given vector.
• Pointing inside volumes: the normal of skin surfaces of selected volumes are swapped to point inside its volume. Surfaces shared by more than one volume are not swapped.

Note: With the Color option set (available in the Contextual mouse menu), all surfaces or elements are drawn in filled color. Their front side will be drawn in their regular color, and their back face in yellow.

Note: Volumes are correctly oriented by GiD, regardless of their surface orientation.