Atomic Perception

One thing to try, is to assign a default material. Then make sure the viewport Material button is turned on (it is by default), and activate the lighting with shadows button. You may want to add an area light or environment light as well.

Try using a particle system instead, then you can add the box as a collision object the points will avoid. There are a bunch of tutorials on shape changing points, look one up.

Use python to navigate the node tree, examining every parm value. Use the expression() method for each parm to return the expression value as a string, and compare that to $FSTART.
https://www.sidefx.com/docs/houdini/hom/hou/Parm.html [www.sidefx.com]