Point Projection

I don't understand what you are trying to do. Are you cutting the model by a plane, so only the part on one side of the plane remains?
Or are you trying to intersect the polygons with each other for something?

Erik, thank you for your reply - I am sorry about the confusion on my earlier post. However, I now think the problem is not in the "cutting" of the polygon(s) but rather in triangulating them. The triangulation of the modified/cut polygon(s) is called using the Ear-Trimming algorithm which worked great in 2-Space (not so good in 3-Space).

For Example:
If I start with a polygon: (1,0,0),(3,0,3),(3,2,3),(2,2,2),(2,3,2),(1,3,0) and triangulate it I get 4 triangles:
Triangle 0:
(1,3,0),(1,0,0),(3,0,3)
Triangle 1:
(3,0,3),(3,2,3),(2,2,2)
Triangle 2:
(2,2,2),(2,3,2),(1,3,0)
Triangle 3:
(1,3,0),(3,0,3),(2,2,2)

Rendering the above 4 Triangles yields an odd-looking image. The z-coordinates look out of place in that they don't blend with the over all polygon (jutting out at almost right-angles).

At this point I am unsure if the major issue exists with the triangulation algorithm itself or somehow the z-coordinates need to be "smoothed" via some kind of linear interpolation between resulting triangles.

Any ideas would be great :)


Thank you.

Quote:

Original post by dinaharchery If I start with a polygon: (1,0,0),(3,0,3),(3,2,3),(2,2,2),(2,3,2),(1,3,0)

That's not a polygon!

To be more precise, it isn't planar (flat), so you shouldn't expect to be able to render it out of flat triangles.

Are the resultant polygons also convex?
It's very easy to triangulate convex polygons. For example put one new point in the middle, and combine it with every edge of the polygon.