Thanks alot for your linked blend-file with masked areas and kind info!
Yet feeling totally noob-terrible for my part: Nothing moves when playing the timeline. And beyond frame 50 the particles disappears.
This is what I see: https://drive.google.com/open?id=1VoTgBOUeZktjg0so7vsfSlID3J5n0_wF
I'm sorry to say I can't comprehend what is going on and do not grasp the concept (ie. “... controls spherical texture”). I've long ago learned about Texture Space (yet cannot get the yellow box with dotted line meaningfully to switch on in the file). Is this related to your setup?
Trying to “deconstruct” the file also leaves me puzzled. The object named “Cube” to make it behave as a normal one I can’t ”reset” (==deleting the material attempting to make it visible, adding new materials etc. just to figure out the nature of it) Even the use of the 1-29 linked collections I don’t understand.
It’s a bit up hill (to me;-)) for the moment as you might see but could you give me a cloue of the idea behind?
I Guess I must have to learn more about the Blender texture space concepts you use before I understand your explanation/file. Would very much like if you have links or perhaps some words to search for. With gratitude for your helpfulness!