Anim8or Community
General Category => ASL Scripts => Topic started by: Nate_Bro on January 08, 2008, 08:47:55 pm

I'm working on a particle system, but I'm haveing trouble with reflections. I have colision detection, but when the particles need to change direction, my formula is not very good.
all i'm doing now is fliping the axis...
like (4,5) == (4,5)
Thanks for any help you can provide,

You need to reflect the incomming vector off the plane of reflection. Your computation assumes that the plane is x=0. In general the direction of the outgoing vector is:
Vout = Vin + 2N*Dot(Vin, N)
where N is the plane normal, Vin is the normalized incomming direction and Vout is the outgoing direction, (You need to normalize Vout after this computation.)
Here is a detailed description. See equation (3) (but not that the normal is reversed from my formula so the subtract the terms instead of adding them).
http://mathworld.wolfram.com/Reflection.html (http://mathworld.wolfram.com/Reflection.html)

when i read the first post i wasn't sure what you were asking, but now i get it.
had i known i would have said: to make bouncing realistic would require a bit of vector math, i don't know the specifics.
i believe steve has put it in pretty good terms

Thank you Steve, that helps a lot! I'm still new to vector math and normals, but I'm slowly learning :)

Thank you Steve, that helps a lot! I'm still new to vector math and normals, but I'm slowly learning :)
I hear what you're saying about vector math and it's role in 3D modeling software like Anim8or. I wish that someone would post some articles on how Anim8or uses this information to do stuff in Anim8or. Steve, you created a quite awesome product with some very advanced features. I use Anim8or all the time now and seem to grow more fond of it the more that I play with it. Leroy.