Issues with creating drawing from object

ok, i’m having issue with trying to create a 2d drawing so i can machine my part.
i have created a model and used the union to make the full object. however when i switch to drawing mode the object will not be selected.

what are my options

Could you share a bit more about the issue—are you seeing an error message or missing features?

If you’d like, you can submit a ticket on the support portal

ok, hopefully this will help explain more. first my goal is to create a model of a structure that i am going to be welding. so it is made up of a bunch of square tubes. i started out of tubes and placed them in the structure to what i needed to weld. From there i clicked on a bunch of the tubes and used “union” to create a full part. now i was not annal in amking sure my tubes 100% matched the butt joins etc. instead once i unioned them togeather they looked good. now if i click on any of the structure it turns blue showing the full stucture selected. At this point i could send that to a stl and 3d print it. however since i am welding this from tubes i need a drawing to show the lengths to cut, i need the Dims to know where to drill my holes etc. So when i now try and create a flat drawing so i can place the dims on that… i cannot select any of the object. the software will not find or allow me to select this “union” part.