you want to loft from the undended face to the dented position.
I think this would be best with surfaces:
1 - create the undented face (as a surface)
2 - offset this to the max depth of the dent
3 - create a sketch and draw the "start" and "end" of the dent - the edges where you want the dent to start to deform away from the original face and also the patch of the "fully dended" area
4 - use split face to remove the unwanted areas (inside the original face and outside the fully dented patch)
5 - use loft to go from the inside edges of the starting face to the outside edges of the dented patch - choose tangential conditions for both
6 - stitch all the surfaces together and then thicken the quilt to give you a solid.
alternative method #1: instead of having a dented patch/shape you can loft to a point (and have that tangential), depending on whether you want to control the shape of the dented patch.
alternative method #2: with 2015 (and I guess into the future), I guess you could probably use the direct/freeform modelling features. I've not got 2015 installed atm so I couldn't comment further.
I hope that makes sense - 2014 file attached.
Sam M.
Inventor and Showcase monkey

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