[Quang Nguyen]

Thanks Dan,

I got it like this:
u = [-1, 0, 0];
v = [0, -1, 0];
w = [0, 0, -1];

And it worked for my case. I wonder if you could help me simplify it more to speed up a little bit?

You saved me most times Dan!

[Quang Nguyen]

Hello Dan,

If I don’t have a layer to input but a 3D vector, how would I put it into this code?

Best regards,
Quang.

[Quang Nguyen]

Hi Michael! Thank you for your attention!

My emitter shoots several particles up and spread out around the Y axis like a cone. When the emitter moves, I want the cone to rotate along with the velocity of the emitter, like a firework trail. It can be easily done in 2D by rotating the Z. But in 3D I don’t know how to transform all of them.

[Quang Nguyen]

I think you can shift the Z anchor point of your 3d layer and rotate it around the Y axis.

[Quang Nguyen]

Mr. Dan, would you help me with the position as well? I want the child to update its position while the parent rotates, scales and moves so that the child’s position remains unchanged in world space. I am making a particle system like the one you guided before to export it to my game.

[Quang Nguyen]

Dan Ebberts has helped me solve it with this:

u = fromWorldVec([1,0,0]);
v = fromWorldVec([0,1,0]);
w = fromWorldVec([0,0,1]);

sinb = clamp(w[0],-1,1);
b = Math.asin(sinb);
cosb = Math.cos(b);
if (Math.abs(cosb) > .0005){
c = -Math.atan2(v[0],u[0]);
a = -Math.atan2(w[1],w[2]);
}else{
a = (sinb < 0 ? -1 : 1)*Math.atan2(u[1],v[1]);
c = 0;
}
[radiansToDegrees(a),radiansToDegrees(b),radiansToDegrees(c)]

Thank you all!

[Quang Nguyen]

Oh my god Dan! You saved me on this! It worked like magic! Thank you very much! I am always your fan!

[Quang Nguyen]

Thank you Walker Soyka for your solution. Unfortunately I want to make the particle system as simple as possible for my users to use and reuse. I should keep the number pf layers to minimum and parent the particles to the emitter and just these 2 types of layers so that when my users copy and paste they can make a new particle system in the same composition.

I have successfully counter the position and scale of these child particles, but for rotation in 3d it is very difficult. Can you help me with the method of no intermediate null?

[Quang Nguyen]

Counteracting parent’s orientation/rotation in 3D is what I’m looking for. Can everyone help me continue on this problem?