What is wrong with this Form Tool?

I have been trying for hours now to add a gusset into this sheet metal part.
It needs to be like in the attached photo, just a small dent really...

I keep getting the error:
"the thickness must be less than the minimum radius of curvature for the form tool"

Can anyone help with this please....?

3 Answers

no tools for this but you can made it by features
notice: your model not a right sheet metal part
please check my model (features & Configurations)

yes my version is 2012 but i upload parasolid part for you

Use the indent tool in the same manner that Saeid used the cut-extrude and extrude features, its a little easier.