How to extrude subd solid?

I want to extrude a plainer subd into a solid. Instead I get an open extrusion.
EXTRUDE FROG.3dm (335.9 KB)

Thank You

use OffsetSubD, but first you should fix this part

when you zoom in in flat mode you see that you have some overlapping edges where the normal inverts

that is going to cause a lot of hick ups. best you just delete that vertex point the inverted arrow is standing on. offsetting then should work. you might have to change the edges a bit to get back to the exact shape or make a new edge if its crucial.

Thank you very much!

solved ?
please mark encephalon answer as solution - so others don t need to open the topic to see it s solved.

thanks