It all depends on what you are making the model for - if the the inner walls are going to be seen, then model them otherwise don't bother. As for the circle, try different #'s of segments to see what works best for the current project - there is no correct answer.

Hi folks. For me, the quickest way of repairing this damaged cup would be to: 1 - Delete one half containing the damage. 2 - Copy the remaining half. 3 - Flip the copy. 4 - Join the two half. 5 - Smooth the junction line. It is faster to do than writing this post. Just ideas.

You need more leverage so a larger gear might help. Otherwise I have no idea

Window -> Styles go to the Edit tab, select the first icon (3d box with no faces, only lines), and uncheck endpoints. My preference is to make sure all of those are unchecked as they slow down your model. Only use them if you want them on to print or export. -Brodie

Try clicking a hinge then another hinge, It creates a gear between them.

You simply need to group different groups to get the result you want. Tiring and troublesome, but i bet it will come out great.

@tachyon said: SketchyPhysics3? Are you referring to the 2Beta version that is in the project wiki page? Also, if you guys don't mind, do you know what's going here: http://www.sketchucation.com/forums/scf/viewtopic.php?f=61&t=18454 I got the bottom hinge to work, but the top one is giving me grief. No, he means Sketchyphysics 3. I'm not sure which wiki you're talking about, but here's the newest one, organized by the community. http://sketchyphysics.wikia.com/wiki/SketchyPhysicsWiki . It's kinda a WIP but you can find links to download SP3 RC1 on windows and mac, and info on SP3's new features, along with the bigger user projects, a couple of tutorials and notes about the joints.