Once again this has to do with the matrix tutorial on highend3d.

I dont understand this:

Select particleshape1 and open the expression editor.Add the runtime expression

index=rand(1,26);

Play the animtion and you will find that each particles are now instancing a random letter and changes every frame. It is now near the effect we want. But we still need to write some expressions to control the motion of each particle.


Select particleshape1 and add one another array attribute "gate". It has not much meaning , just for used in the expression. Add the runtime expressions below to the particleshape1.

particleShape1.index=rand(1,26);
vector $temp=particleShape1.worldVelocity;
if ($temp.y<=rand(-10,-5))
{ particleShape1.gate=1;};
if ($temp.y>=(-1))
{particleShape1.gate=0;};

if (particleShape1.gate==1){ particleShape1.acceleration=<<0,rand(20,25),0>>;
//print("aaaa");
};
if (particleShape1.gate==0) {
particleShape1.acceleration=<<0,rand(-25,-20),0>>;
//print("bbbb");
};


You can find the tutorial in this place to see the whole thing, any help would be greatly appreciated; https://www.highend3d.com/maya/tutorials/harley1/

Thanks!

P.S. If someone could tell me where I could find a better or more clear explanation of how to do this, please tell me! Thanks again!