So in attempting this project, I chose to model my own desk lamp, and rough modeled the first and second parallel arms. My issues stared when I realized I had no way of joining my two parralel sets of bones at the mid point (see mid arm back - mid arm front bones in the screenshot) Ideally I would want to join them at the mid-arm to establish the top of the lower parallelogram and bottom of the top parallelogram, but as a bone is a parent of a mesh, I can only get one bone to control that mid point.
How do I create parallelograms like this? I’m hoping to find the solution in a later lecture - if anyone can point me in the right direction I would be grateful.
I don’t quite understand what you are trying to do. You want to join the bones back in the parallelograms?
Do you really need two set of bones to control your parallel arms? It would be much simpler if you would just use one. In your case the lower arms can only rotate on Z right? And they really can’t do it separately, so you could use just one bone. For the upper part it’s the same.
I guess the only difference in using two parallel arms is when you move the lamp shade and the parallelograms constrict the movement of the arms so they can be close or further apart. If you want to achieve that level of realism in your mesh then I think you need to use bone constraints, possibly with other helper bones. Like have the master bones and then another set of bones for the other arm which is not directly parented to the master, instead use constraints with offsets.
I am not sure this would be the best way to go but at least I would try go that way. Hope this helps!
Thanks for your help Jax. Ive taken a quick look at the problem again during my lunch today. It looks like your right. - using two bones for the verticles with a rotation modifier (better than a single bone as it allows the distance between uprights to change), and using bones for the horizontals with ‘limit rotation’ modifier might just work. I’ll try a more thorough test tonight and post my solution here if it animates convincingly.
Hello.
So heres how far Ive got - its better but not perfect. Rotating the whole lamp on the lower pivot still tends to throw the bones askew. My bones are all measured and placed to match the length of the arms. There is still a small amount of distortion - but a forgivable one.
The real problem that still remains is, because the inner arms are effectively floating, the do get out of sync. The front upper arm in particular quickly gets into trouble. What I really need is a way of connecting the lower front and upper front bones to the mid and top point joints.
