There are many tools available to produce wrap patterns for tube/pipe mitering but we like to use solidworks to produce them, ensuring your template updates with any design changes. This method will work for both weldments, sheet metal and general 'boss extrudes'.
Here's how we do it.
1. Here we have our frame that we wish to make and the item we'd like a flat pattern for (red).
It is first worth mentioning that solidworks 'flat pattern' command will give you a flat pattern of the mean circumference not the outside diameter circumference so best practice is to thin the wall thickness to as little as possible. We are going to use 0.1mm for this example.
2.Start sketch on end face of pipe and offset OD inside by 0.1mm
3. Add a small cutout to your preferred seam quadrant. This is going to allow the pipe to be flattened.
4. Extrude cut this through all of your pipe excluding all other bodies.
5. Snap to sheet metal tools and select "insert bends".
Select the linear edge of the now split seam
and press ok.
6.This item can now be treated as if it were any other type of sheet metal component.
We then recommend making a configuration of your part as a "template config" and suppressing all the above mentioned features in all other configs.
This ensures your cut lists and drawing views remain parametric and true.
Chucking on a reference dimension is also useful to check if the template has printed 1:1 or not.
Thanks for reading.
Matt, Rubix Design