Finding points in 3D space after rotations/translations (images included)

Alessandro · 2012-01-28T13:49:01

Hi, I'm trying to figure out how to retrieve points in 3D space in the following scenario. If you take a look at the included image (click it to show it full size), basically I have a head model with a green hair attached to a hook point on the head itself. The triangle coordinates (T1,T2,T3) of the hair follicle are known, and also hair points (H1,H2,H3,H4) are known. The head (and the attached hair) are due to rotations and transformations in 3D space. I do not have access to that information. What I know are the final triangle coordinates (T1,T2,T3) and the hair hook point (T3=H1). At this point I'd like to be able to calculate H2,H3,H4 so that they follow the original hair direction. I'm at odds with math, but I thought I could do it with vectors. If I save H1H2, H2H3, H3H4 before doing any transformation/rotation, could those be used later? I'm a bit confused...

Math and Physics Programming

Started by Alessandro January 25, 2012 02:00 PM

11 comments, last by alvaro 12 years, 2 months ago

Alessandro

306

Author

January 26, 2012 10:06 PM

Yes, already tried it and infact, normalizing the vectors as you suggested made points maintain the same distance.

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Alessandro

306

Author

January 28, 2012 11:05 AM

Alvaro, in case I need to use this routine on quads, instead of triangles, I suppose there is not much of a change. If T3 is the origin point (the one with the hair attached to), I need to get the two adiacent points coordinates and use those to do the math, right?

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