How to reverse direction of solid trim?

I am trying to make a 3D voronoi pattern inside this brep but it is trimming in the wrong direction. I have tried flipping all the brep surfaces and joining but it won’t work. Any advice would be greatly appreciated! :slight_smile:

Scripts (14.3 KB)
Models 1-10.3dm (2.5 MB)

It looks like your input BRep is not closed; the error on the red component is that trimming is only supported with closed Breps. If you go to the options and select a single backface color like orange in my case, you can see what is going on, the orange bit is folded, you need to correct that.