Getting a crease when using a Mirror Modifier I'm trying to model a spaceship and I ran into this weird predicament. I'm using a mirror modifier as can be seen and I get this annoying crease:


If I enter edit mode, you can see that the verticies are connected:


And adding mean crease doesn't fix much:


What's a good way to fix it?
You have some non-manifold inside faces caused by the mirroring. Select and delete them with X or Del.