Some day back in my old days, in the beginning of my new 3d life i was exposed to help riggers and VFX department on how to rig physical properties like vector forces etc with control curves. And i was surprised what an easy task this was and how much of a problem this meant for some people. Although i understand it could have been ages for them since they left school (yes, this is not even university level maths!) you probably didnt get a scientific path in high school. Anyways, im far from being a math nerd myself, and if you are an artist not very familiar with vectors and matrices you will probably discover how surprisingly easy this is.
What we want is basically to control the direction of a vector, for example nucleus' gravity by means of the rotation controlled by a handle/curve control.
So basically this corresponds to rotating a vector by a rotation matrix!
vr = [M].vo
being "vo" the original vector direction and "vr" the rotated vector.
Basically you perform this operation with the vector product node and hook its output in this case right into the axis unit vector of a vortex field.
In the outliner you have this marvellous, beautiful arrow that serves as the possible curve control of a hipothetically more complex part of a rig, which indicates the initial direction of the vector.
And the results are here in a demo video using nParticles and field forces!!
God! that was quick!! i think this is the shortest blog entry ive done so far!!!! and in the middle of a working week!!!!
Hope you enjoyed!
