Yay, just finished the second installed attic-hatch build & install. Number three is easy, hatch is fine, just needs insulation. Number four is more complex. Some sketching and thinking is required there. It's a large pull-down ladder hatch.
After a bit of work on paper, I find #Blender pretty nice for working through some ideas before building a thing. Gotta keep telling myself to not get too fancy.
I could go the next step and do scale drawings and such, but really with a concept figured out, just figuring it out on paper as I build it is fast and easy.
…unless I'm trying to procrastinate, then I'll do a scaled design with lighting effects and textures – anything to avoid actually building the thing.
@ottaross
Ross, I’ve never actually ‘tried’ to procrastinate. It just kinda happens.
But after seeing your post, I’ll give it a try.
Maybe tomorrow.
Or next week sometime. 
@jd Put it on your calendar. lol
@ottaross Don't forget to defrost the freezer while you're at it