Jointing 3D Jointing Resources

Dont have any experience with modeling parts like but for references you can download lots to look at from here: Search Thingiverse - Thingiverse

Ive been poking at some models for a couple of day, not made any, but from the look of things a single joint can be done by making a limb, placing a ball intersecting it where you want the joint, subtracting it to make the cups, putting a same size ball back and merging it with the part of the limb you want it on.

This is my first go at trying what i just described to make an example of what i mean: imgur.com

First pic is a leg with the ball placed.
Second is with the ball subtracted.
Third is the ball added back in, joined to the thigh and a cylinder about to be subtracted to make the channel.
Fourth is a wedge to notch the ball so the string has someplace to go when when bending the joint.
Fifth is the result.

Obviously this quite crude and quickly thrown together but at least a basis for it, you would then clean up the cuts to make the edge of the cup look nice and blend the parts of the ball that dont need to be stick out excessively into the rest of the thigh.
The back of the knee may need a bit of a wedge removed to make space for the movement.
Also i think the ball should be shrunk slightly to make some clearance for it but that will depend on your printer, if its super accurate it might not be needed.

If you wanted a solid front with only a straight line at the knee you could cut the leg at the knee and recess the ball slightly backwards, that would make it so there straight position would lock and the ball be a lot less visible from the forward direction.

Double joints can probably be done in much the same way but using two balls stacked, joined to each other, subtracted from the limb, wedges cut and the cups cleaned up.

 

Check out Digidolls on youtube!

 

Very interesting, the variant of slightly protruding single ball joints seem to have very good mobility.

Ive been playing around with remixing the Alternate Polaris doll from thingiverse into the shape of everyones favorite dragon loli.

Got everything except the upper chest and the head complete and printed, gonna do a printable skull cap with the hair/horns on it to begin with since i dont know how to make wigs.

Here is what ive where ive got next to a the model for a full sized 1/3 doll:

(the head you see is off the 3d model i found and have been using as a reference, not actually a printable part yet.)