when modeling something like a car door, I use a split line to break out the surface that represents the door from the rest of the model. This works just fine but you can't really see the door because there is no gap between it and its surroundings like there is in a real product.

So my question is what is the best way to achieve this gap? should I just build it into my split line sketch then delete the small 2mm strip that will be running around the edge of the door? Or would it be best to isolate the door and add a ruled surface perpendicular to the door edge, offset it a couple mm's then use the offset surface as a trim tool?

Or perhaps there is a better method?

Suggestions?

Thanks