Creating of a utility site improvement from Custom box shapes and extruding vertically

I have pull boxes which are for ATMS, Finer etc. they have a radius at each corner. I cannot find a way to create a improvement from such line work. I know you can create utility’s but it seems they are interperated as a pipe. Extruding outworks rather the down words. I know you could copy a box from the external library but when you edit it it only handles it like a square box. It would be benificial to be able to create a improvement which closed line strings such as the ATMS pull boxes with radius’s that will drop verticall and hold that shape. I’m am using thins for Asbuilts on the project. I could just use a rectangle box but would be great to be able to use anything. This is something that I have thought of for years. Or a extrude command such as Cad. Object shape can be extruded and displayed as a solid for 3D visualization. I definitely think there are many upgrades that could be done to this module. Such as custom Manholes that are represented properly. For example Eccentric, with the center of lid offset rather than everything being just a typical cylindrical shape. Cad has these options plus more. I love TBC but sometimes have to revert to Cad for such things as these which I would rather not do. Also I have always thought that it would be really beneficial if you could explode the structures and have the line work for the boxes which can be exported to for the field. Makes locating corners rather than just have a center point. Useful when we have to cut PCCP or Asphalt to raise to FG. Many times they get paved over. It identify the orientation. I think a simple extrude command would be extremely beneficial in my opinion. I could use it in many ways for 3D visualization such as As built data presented to the client. For linework of structures the work around I use is to export structure as .xml, import into cad, export as .IFC and use the IFC explode command. It works but in several steps and time consuming.