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Member Since 11 Sep 2013
Offline Last Active Apr 13 2014 09:01 AM

Topics I've Started

Linear Velocity and Angular Velocity Point of Intersection

04 April 2014 - 08:43 PM

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, ® 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:


is talking about adding them together if you have certain info...i tried but I am extremely lost.
Thanks for your time.

To Square Root or Not To Square Root

06 October 2013 - 04:13 PM

Hi Kastor here.


I have two algorithms for collison detection. One uses a square root operation, the other is the same operation without it. The problem is the square root operation is only 23 operations, whilst the one without the square root is 43 operations, a whoping 20 more opertations. Bot have phases and can be broken up into parts. Which one should I go for. Should I use the one square root opeation or not?


Thanks a bunch ;)

When to Use Interpolation in Animations

11 September 2013 - 12:00 PM

So, I am making a game with the help of Blender and Collada. Then I got to making the aimation system and realized that for the animations for the bones I should probably not use any interpolation in a single animation. As in, when you aniamte in blender you don't animate on every single frame. Therefore there is interpolation going on, usually cubic/beizier. However, if you are exporting the animation in Collada, should you bake the animation and then send it to your game. Becuase the later would be to export less matrices, creating a smaller file, but more computations at run time. Because instead of just doing the matrix multipications, you would also need to do an interpolation conversion. I only really see interpolation useful between animations and paramterizing animations. But an animation itself should have a full set of matrices per bone for each animation. If we can calculate it before runtime and it will always be the same, why not?


Is what I am saying make sense, or is there a huge concept that is currently flying over my head? I want to start programming this thing, but dont want to make a huge mistake resulting in me doing the whole project again. Just wanted a few pointers from people who have been doing it longer.


Thanks in advance!!  ;)