Uh-oh...many things are contagious around here. ;) Okay, this trial used the P4Male. First, I eliminated every object I didn't absolutely need to show this -- which you wouldn't do; he would still have shoulders, in other words. ;) I selected just the Head, copied it, then pasted it. I called the copy HeadIn. I then made the copy slightly smaller globally. Select Head. Select HeadIn. Make Boolean Difference. Now the head is hollow in a way that gives some actual depth to its "shell." I named the difference HollowHead. I generated a Rock (Vue 4 sure made that easy! ;) ) I lined the Rock up where it would look like a nice place. Select HollowHead. Select Rock. Make Boolean Difference. I named this difference BrokenHead. Render preview. Head is broken. But -- and this is what you were running into also -- the broken section extended well beyond the Rock boundaries. I don't know why this is. :/ Select BrokenHead. Copy. Paste. Ungroup the pasted copy. Make sure its parts (HollowHead and Rock) are still selected (should be automatic), then make a Boolean Intersection. Name it HeadChunk. Move HeadChunk to the desired position. This render shows BrokenHead and HeadChunk.