Archived

This topic is now archived and is closed to further replies.

Unit sphere...

This topic is 5114 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

I'm trying to create a unit sphere by recursively subdividing the faces of the four triangles of a tetrahedron centered at the origin, giving four new triangles for each face. What then? I need to get those points on the unit sphere. Do I normalize or something? I have a feeling that it's so simple and right under my nose...please show it to me EDIT: forgot a sentence!!
Human beings, by changing the inner attitudes of their minds, can change the outer aspects of their lives.
William James (1842 - 1910) [edited by - rohde on December 14, 2003 12:11:51 PM]

Share this post


Link to post
Share on other sites
Basically, you''d just subdivide and push it outwards along the faces normal. Only problem is calculating how far to push the point out, normally this is calculated based on the difference in normals between the 3 corners (the sharper the angle, the further out it is pushed). I am not sure the exact algorythm off hand and would have to play with it a bit to figure out a good way .

Share this post


Link to post
Share on other sites
quote:
Original post by Ready4Dis
Basically, you''d just subdivide and push it outwards along the faces normal. Only problem is calculating how far to push the point out, normally this is calculated based on the difference in normals between the 3 corners (the sharper the angle, the further out it is pushed). I am not sure the exact algorythm off hand and would have to play with it a bit to figure out a good way .


That''s what I meant with "right under my nose": face normal!! Doh...thanks



Human beings, by changing the inner attitudes of their minds, can change the outer aspects of their lives.

William James (1842 - 1910)

Share this post


Link to post
Share on other sites
with a tetrahedron, you''re gonna end up with some pretty substantial "corners" in your mesh. if you subdivide and normalize each point, you''ll end up with smaller triangles near the original corners of your tetrahedron and larger ones towards the centers. you can alleviate this somewhat by starting with a dodecahedron or even an icosohedron, but it''ll still be an issue...

Share this post


Link to post
Share on other sites