Here’s a screencast:
The surfaces were matched on each side before joining.
My setup:
Model Name: Mac Pro
Model Identifier: MacPro5,1
Processor Name: 6-Core Intel Xeon
Processor Speed: 3.33 GHz
ATI Radeon HD 5870
Memory: 32 GB
It’s impossible to guess without the model, but I suspect the problem is because on the sides, four surfaces are meeting at a single corner. I think that’s something to be fixed for V6. Can you move the seams or merge surfaces so you don’t have 4 surface corners meeting at one spot?
It would be much easier to figure out with the 3dm file.
I went back to an earlier copy of the model and rematched the surfaces. I thought the operation would be complete along the selected seams but it’s more reliable if I do one side and then the other. I joined the surfaces and tested the fillet again. This time a surface didn’t disappear but there’s a strong artifact on the fillet
http://www.screencast.com/t/f0JE26hZkjW
I’llDeoderant.3dm 2.zip (330.9 KB)