If you like to think in code this CAD program is great, especially if the design can be broken down into primitives. This is an example of a very basic shelf I designed but I have been using it for everything from designing mounts to hold PIR sensors to a shed that will become the new Clacktronics workshop!
The interesting thing is that you end up with segments of code that can represent the real life segments you need to cut to construct your design. Even better if doing something more complicated you can make it parametric by using variables and even iteration.
I have done slightly more complicated tasks with it apart from shelving! Here is an example of a job I did where I used mini PIR sensors in 3d printed mounts so they could be used to detect human movement but on a narrow beam.
The PCB slotted perfectly into the mount and was held in with hot glue. Details for this project can be found on the Clacktronics Github page.