Why offset cannot be created on attached sketch? It is imported from Adobe Illustrator CS6 as a DWG file.
There are some small curves that have a minimum radius that is smaller than the offset amount that you want. You need to rebuild a sharp corner here (dotted lines).
Then you can make a larger fillet on the corner to allow a larger offset.
There are some small curves that have a minimum radius that is smaller than the offset amount that you want. You need to rebuild a sharp corner here (dotted lines).
Then you can make a larger fillet on the corner to allow a larger offset.