Convert z-coordinates to y-coordinates from a threshold

Hi all!

I’m creating a black hole on TouchDesigner. I have a breakthrough but it doesn’t meet my expectations. Let me explain. In the diagrams below, you can see that I’d like to switch a shot from a certain threshold. In my case, when I get closer to 0 to z I’d like to convert the values of z to y and vice versa (if I’m not mistaken). I’d like to apply this mechanic to a point cloud from a TOP. Here’s what I’ve already done that will give you a vague idea of my expectations.

Thanks for reading and I look forward to hearing from you!

I think I understand that you want the “light bent from the stars behind the black hole” to appear when the camera gets to a certain position?

It depends how you’re getting your coordinates but if you’re using r,g,b for x,y,z particle positions you could use a Reorder TOP to do the particle switching and maybe a Logic CHOP being fed camera position to trigger a Select or Switch TOP in the network.

It looks like you only want to effect particles in the negative Z hemisphere? So I guess you’d use a Threshold TOP to select those particles based on the blue channel.