Modifying a degenerate surface normal

By using the Normal to Degenerate Surface command you can very easily define the normal of a degenerate surface. You can proceed as follows. You can follow this step-by-step example by loading file:"DegenerateSurface.e3"



Using the Normals command under Analysis, you can see the normal at the topmost vertex of the surface is not univocally defined:


 

1

Select the degenerate surface to be modified (please note that non-degenerate surface selection is not enabled). If the selected surface is not a NURBS, you will be asked for a confirmation to convert it into a NURBS (unless you have deselected the Ask before converting check box). Once the surface is selected, the normal at the topmost vertex is automatically defined and a preview is displayed. The command enables you to correctly define the normal but, as you can see, this inevitably has the effect of modifying the shape of the surface.

2

Click or to confirm. Click to discard your changes.

Now, if you check the surface normals using the Normals command under Analysis again, you will see the normal at the topmost vertex is correctly defined.