While working on an upcoming beginners guide to Wings, I put some thought into something I had never really thought about before… what the heck was the “Crease” command for? Functionally it seemed identical to extruding an edge along its normal. After some messing around though, I figured out the very small but somewhat important difference between the two commands.
The following video shows the difference in action.
Extrude vs Crease in Wings 3D
As you see, with Extruding, a 5 sided polygon is created just past the edge that was extruded. With crease the polygons are created using the next available vertex along the edge. This is a very minor distinction, as otherwise the two functions are almost identical, but the effect is most pronounced once smoothing is applied.
So, damned near the same, but slightly different. But in answer the question “Whats the difference between extruding and crease?” the answer is “not much”.