This script allow you to create Voronoi cells based on any object vertex cloud or any particle system.
This script based on FRACTURE VORONOI script by GARP
1) Download script
2) Run it via menu "MaxScript - Run Script" or DragAndDrop it on 3dsmax viewport
3) Choose "Pick container Mesh" button and click on the mesh you want to become cells' container. (Cells will be cut out of this object)
4) Choose "Select group of objects" and select objects you want to serve as a pointcloud(cell centers) inside the container mesh. You can use any geometry or particle systems. Note what particles with geomerty shapes will be understandable as group of geometry, not like a points. But if you will set a Vertex type shape in PFlow then particles will be correctly transfered to point cloud.
5) Choose "Do!" and wait.. (please dont use hi-res meshes if you don't want to get a damn-long processing)
All used objects (Source object) will be hidden so you can back to them any time.
Cells will inherit colors (but not materials) from the source objects, so you can easily select part of cells from the same source by the color (Edit - select by - Color).