Flipping the Surface Normal

[Mr. Mattia Brenner 6]

The easiest way to flip the normal of a given surface is by reversing one of the surface directions u or v. In a NURBS/B-Spline surface this can be done with the command .reverse(1,0) or .reverse(0,1).

In a Metasurface you can reverse start and end position or you create an image surface and in the u or v domain you enter [1,0] instead of [0,1].

[Mr. Claus Abt 14]

Arne was so kind to provide a couple of reverse, swap etc. functions recently: they appear as text in the upper toolbar once you have selected a pointbased surface or curve.

[Stefan Harries 3]

Hi folks,

 

Further to Mattia's and Claus' entry I would like to add a small example. It contains one simple B-spline surface and an image of it. The image is translated sideways in order to show both the source and the image in the same figure.

 

When both the U-Parameters and V-Parameters run within the interval [0, 1] the surface normals point into the same directions. However, reversing the V-Parameters of the image to [1, 0] flips the surface normals. To illustrate this a meshEngine was utilized on the two surfaces. (Within a meshEngine the normal direction is indicated by transparency in one and opaqueness into the other direction. Note that you can also change the normal direction within the meshEngine itself by selecting the Reversed option.)

 

Kind regards,

Stefan

 

P.S. You may want to check what happens when you change the U-Parameters from [0, 1] to [1, 0] and set the V-Parameters to [0, 1]. What does this do to your meshEngine (which I deliberately set up as an asymmetric mesh)?

surfaceNormal.fdb