So, I have been studying angular velocity and linear velocity--and I want to use this information determine if a ray intersects a plane. linear velocity = dp/dt angular velocity = dΘ/dt thus for linear velocity, you have a point in space: the intersection point could be described as I = Po + rV (Po) position initial, (I) position final, (V) linear velocity vector, (r) a scalar then, eloquently you can set it to the plane equation (Pp) point on plane, (Np) normal of plane (I - Pp)*Np = 0 I*Np -Pp*Np = 0 by replacing I for the above equation (Po + rV)*Np -Pp*Np = 0 when worked out you can find r thus Po plus the velocity vector times a certain scalar will get you the intersection point. How will this change if you are dealing with angular velocities. If you guys remember, rotation always stumps me this guy, in his blog: http://www.wildbunny.co.uk/blog/201...tion-for-dummies/comment-page-2/#comment-3697 is talking about adding them together if you have certain info...i tried but I am extremely lost. Thanks for your time.