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C# Face Normal Calculations

Started by awood969 Mar 29, 2011 at 2:47 PM 3 replies 2.3k views

Original Post

Mar 29, 2011 at 2:47 PM

Hi there,

Question is the title, how do you calculate face normals? I'm doing a little project in C# without using any graphics API (DirectX, OpenGL etc) so I need a way calculate face normals, I don't fully understand the theory im afraid :-(

Any help would be very appreciated!

Thanks
Andrew

Buckeye

Mar 29, 2011 at 3:08 PM

A face normal is calculated using the cross-product of vectors forming two sides of the triangle, and sharing the same origin.

I.e., given a triangle with 3 vertices v0, v1, v2:

normal = cross( (v2-v0), (v1-v0) )

Depending on the winding order of the vertices and how you calculate the cross product, you may have to flip the normal. You may also want to normalize the result.

awood969

Mar 29, 2011 at 4:21 PM

Aha, thank you :-D Per chance BuckEye you don't happen to have a handy dandy tutorial that explains how to create a Phong lighting model in c#?

Thanks
Andrew

Krypt0n

Mar 29, 2011 at 4:54 PM

Aha, thank you :-D Per chance BuckEye you don't happen to have a handy dandy tutorial that explains how to create a Phong lighting model in c#?

it's done in c# like probably in any other language. looking that up at google will give you tons of tutorials.

awood969

Mar 29, 2011 at 5:47 PM

That was my first second and third stab before coming on here to post.

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