It could be a combination of those things. Can you test locally?

I'm using Jitter Physics in my project for a more robust engine for mesh collision. It has taken some work as WPF examples are rare and Helix ones are virtually non-existent. It works, but I am still having some issues w/ it. I can try to get a simple example set up, but I might not be able to get to it soon.

I'm wondering if it might not be better to store the files location instead, or look into a different database. I use MSSQL Server 2012 with Entity Framework 4 to store binary data in a different type of program. These data are around 3-5 MB and it just take a few seconds to load it.

Thanks for the idea, but I've moved to importing obj files to get my desired geometry. One idea I did have though was to use a group of cutting planes, my initial experiment look promising, but probably not the best solution.