How to make a roll cage in solidworks?
1 Answer

If you know where you plan to attach the roll cage, model this reference geometry first and constrain to it with the rest of your cage. I will omit this step in my example.
Curvy pieces will require the 'swept boss/base' command, straight pieces can be created with 'swept boss base' or 'extruded boss/base'.
Picture 1
Use 'project curve' select 'sketch on sketch' to combine two sketches (such as top view and side view) into a '3d' curve to create paths for tubes that sweep in 3d.
Picture 2
The paths for 2d sweeps can be constructed with 2d sketches on planes.
Picture 3
'Delete face' command is often your friend when it comes to cleaning up loose ends.
Picture 4
If the cage is symmetric, consider modeling just half of it and 'mirror' the body to complete the model to make the job easier.
Have fun!