Hey there Paul! You mean my post brought you back to the forum? I’m honored! 
The hinge issue utilizing bones wasn’t working as planned because the “rigged” knee would twist or turn at various moments- even with constraints. I’ve seen it work in a few tutorials on Youtube but it wasn’t working for me. In many instances, the control bone would either go “through” the whole leg with no effect , or it would engage the rest of the armature only after I pulled the control bone away on the Y axis and then forward again. There was always a delay before the movement began. And this wasn’t even an animated test- this was just moving with mouse and keyboard.
After that, I decided on another technique…
Constraints and dampers seemed better suited for what I wanted to do. This time, I created a half-cylinder, and using inset and extrude, created panels with an underlying framework.
So far so good. I used all of my settings from the base form folding panel and basically copied and pasted the settings on to each individual panel set. At this point, I thought my theory was sound… until I tried to fold the flaps using the control ring. As before, the panel sets on the “shoulders” or “corners” of the frame work go way out of wack.
I tried local space and world space settings. I tried applying and not applying rotation and scale transforms. The problem persists. What am I missing here?
The above rear view shows how the panels segments on the top, which utilize the X axis and the panels on the side, utilizing the Z axis, fold as expected. The other segments… Uggh.
These constraint settings are for the parent panel, the panel that initiates the fold by rotating on the X-axis.
The Damped Track constraint is for the control ring, that moves along the Y axis. As I move the ring forward, the panels/petals open up. But more on that later…
These above constraints are for the child panel that inversely follows the parent. In other words, when the parent panel folds on the X-axis, the child mirrors the action, with both panels meeting in the middle as it were to create a “tenting” action. I tried variations with Target as Local and World Space and Owner as Local and World Space. I tried different Axis combinations. Nada. So, on to my next brain storm…
So I deleted the framework and started fresh with just the simple parent and child panels to verify that I hadn’t made any errant settings. One thing that irks me is that, the intensity setting is like “all or nothing”.
At any intensity setting, the slightest movement of the Control ring completes the entire movement. It’s like a jump-cut in a movie. There is no ease and out. I tried different intensities… no dice. I tried changing the location constraint on the Control ring and that became a lesson in diminishing returns; the farther I extended the constraint, distance wise, while it did make the movement of the panels slower, it also didn’t allow them to close fully.
In terms of movement cycles, I found that an intensity setting of .333 was able to provide me with the 60 degree angle fold I wanted. But it just snaps into place. So…
This morning I had the bright idea of making an array along a bezier curve. Hey, it’s done for treads right? What could go wrong? Unlike a tank treat, the center of the panels are at the ends, in order for them to stay in alignment. The problem arises when I animate the panels. The panels distort or “flare” at the height of the fold.
In simple terms, all I want to do it have “French doors/ Accordion” shapes fold along the arc of a half-circle, without distortion, with complete control from beginning to end with a constraint or rig.
Now, granted I could easily do this as an animation and be done with it, but I want to try something new.
Any ideas?
