Add Point3D input to VB script?

Hello guys,

I've come across David Rutten's Diffusional Limited Aggregation script and it is exactly what I've been looking for to test some scenarios for university.
Unfortunately, it's written in VB and I don't understand a whole lot, since I'm still a scripting beginner (in Python).

Could somebody please help me to add a Point3D input to the VB-container that makes it possible to change the start point of the dla to any chosen point?

Any help is welcome and appreciated!.

Thanks.

Edit: The script is by Daniel Piker, not David Rutten. My bad!