Line Intersecting Sphere

You''ll get a better response from the "Maths and Physics" forum - maybe one of the moderators could move the thread for you...

Anyway, off the top of my head, you''d probably want to look into using polar coordinates, they''re usually pretty good at this sort of thing

Look up the help file contents for D3DX math functions, see if any of those look like the thing you want.

hth
Jack

Tell me what you are trying to do and maybe I can help. I can''t think of a reason why you would wanna do what you are doing. Cause in most 3d mathematics you use simple repetitive concepts to get what you want. There is a method to tell the closest point on a line to another point.

So once you had that point you can take the distance between 2 points and see if the line intersects the sphere. But if you wanted to get the hit point on the sphere you would would have to add a little more math.

Trigonometry will help you there. You now can create a line from the center of the sphere to the point to the sphere. Then you just need to fine the next point which length is the radius and lies on that original line.

If you forgive the fact that I''ve just published this from MS-Word, you''ll see it''s one of my revision notes on ray/sphere intersection, with code, a fully dimensioned diagram, and a walk-through sample. If you have the slightest knowledge of vector math it should be all you need.

You won''t need the "More elaborate" method at the bottom of the page...

Click here