Delete grains from existing hole ?

[CinnamonMetal]

I want to kill any particles from going past this hole. I was thinking of finding the bounding box of the geometry but how do I find the area of the hole as to tell the particles to die when they hit the hole and or go outside of the hole with grains ?

Edited June 17, 2019 by CinnamonMetal

[nuki]

In your case, couldnt you just kill them if they hit a P.y threshold?

Otherwise you could create an sdf for the hole and kill them inside a sopsolver if the volumesample() of the particles P is < 0

[CinnamonMetal]

@nuki Create a group of the points of the hole, then create a VolumeSDF SOP of the geometry group, then in a wrangler use the volumesample() function; correct ?

[Sepu]

Just use a @P.y threshold as Martin said before, is more straight forward. 

[CinnamonMetal]

I'm rusty with volumes but I do want to know the steps to create an SDF of the hole ?

[nuki]

You have to make a watertight mesh that fits the hole like a plug. If you used a polyextrude, let it output the Sides Group, isolate those faces and polyfill that. Then create a vdbfrompoly, like in the attached file

sdf.hiplc