Inverting Polygons and Polygon Meshes
The Modify > Poly. Mesh > Invert Polygons command on the Model toolbar changes the direction of the normals of a polygon mesh object. It can also invert the normals of selected polygons.
Polygon Normals and Double Edges
Normals are vectors that are perpendicular to the surface of polygons. They indicate the “outside” of an object for the purpose of shading and textures.
Normals are represented by thin blue lines. To display or hide them, click the eye icon (Show menu) of a 3D view’s menu bar and choose Normals.
The direction of the normals is determined by the direction in which you draw the vertices of a polygon.
• If the vertices are drawn in a counterclockwise direction, the normals face toward the camera and
• If the vertices are drawn in a clockwise direction, they face away from the camera.
If the normals of two adjacent polygons point in opposite directions, then a double edge is drawn between the polygons to preserve the integrity of the mesh.
The double edges are considered boundaries and are displayed in light blue if Boundaries and Hard Edges are visible in a 3D view.
You can invert all the polygons of an object by inverting the object itself or you can invert only the selected polygons.
To invert all polygons of a mesh object
1. Select a polygon mesh object.
2. Choose Modify > Poly. Mesh > Invert Polygons. The normals are reversed and the Inverse Normals property editor opens.
If desired, you can mute the inversion by turning the Inverse option off.
To invert selected polygons on a mesh object
1. Select a polygon mesh object.
2. Select some polygons on the mesh object.
3. Choose Modify > Poly. Mesh > Invert Polygons. The normals of the selected polygons are reversed.
Autodesk Softimage v.7.5