Unfolded lenght of plate

I have created this steel plate profile in grasshopper. but grasshopper are not make this plate using tekla plate.If I am taking plate for making this steel plate in tekla it is showing straight plate not curve as I want. its took only item for making this profile. If anyone know about any other option to make this steel plate profile.
And second thing which is I am facing in tekla. When I am creating single part drawing of this plate. I am not getting ecject lenght (unfold lenght) of this plate.
please see if anyone can resolve this issue.
Thank you in advance