Adding force to a picked object

Blitz3D Forums/Blitz3D Userlibs/Adding force to a picked object

JoshK(Posted 2005) [#1]
I have an onscreen rigid body that the user can push and pull by clicking on it with the mouse. I have a vector between the camera and the picked point. I have another vector that is the normal of the picekd surface. Now how would I calculate the force and direction from that? If you pick along the side of a box that is almost perpindicular to your view (you only see the edge) a very small portion of your force would actually be transferred to the box. It would just kind of slide out of the way.


DJWoodgate(Posted 2005) [#2]
I guess you could use the dot product to determine how much force to transfer. I suppose friction comes into it as well. I suspect movement would tend to be against the normal, but I guess there would also be a torque introduced which complicates things beyond my limited understanding. I imagine it would depend on where the centre of gravity is in relation to the picked point.

Anyway is this in relation to ODE? I assumed it would do that sort of stuff for you. If it doesn't it is not up to much.


JoshK(Posted 2005) [#3]
Yes. It will figure out torque, I just need to figure out the force to apply.

I am thinking the crossproduct would be it, or maybe a vector subtraction.