@FRA32 - I don't have a problem with people posting to old threads, especially if they have something new and/or interesting to add to the conversation. The thing that I do not like is when someone leaves a confusing or ambiguous single-word comment which leaves me scratching my head wondering "What did he mean by that?".
@powerphisics & faytree - I'm sure there are lots of 3D rendering programs out there, but few are simple and easy to use for most inexperienced users. That's the beauty of Algodoo. It can be used by people of all levels of knowledge and experience. That's why I think that a 3D version of it would be awesome!