I use "3D Builder" which is a free program included with Windows 8 and 10. It's extremely easy to use compared to something like 3DSMax (which I use as well) - have a go and see what you can turn out.
Check out my other threads - I made a ducting connector to allow easy access to my bulb in a light tube fitting. It was a simple bolt together thing rather than have to wrestle with tape, jubilee clips and flimsy ducting.