Make sharp joints/edges on knees, elbows, and shoulders

[CodyBDrawin']

There are a lot of cartoons and standalone web animations I've seen where characters have fine, angular points on certain joints and areas of their bodies, such as otherwise smooth-faced characters' chins being a point rather than a curve; elbows, shoulders, and knees being at a straight angle (anywhere from 0°-180° depending on how straight it is), and so on. I've only ever made characters and watched tutorials where stuff like knees and elbows are rounded, which yeah, is more realistic, but I'm keen to try out more "pointy" joints and edges.

Problem is that I don't exactly know how to do that - or rather, do it properly, because I have made multiple attempts that were not successful - with bone-rigged characters, assuming it is possible. I'm hoping that perhaps someone around here would know and would be able to tell or ideally show me. The two big ones I need help with are 1) having a sharp angle (also understand that I'm just using the best terms I can for what I'm talking about; I may be completely oblivious to the proper terminology) on where the arm meets the torso and the leg meets the pelvis; and 2) elbows and knees.

[Greenlaw]

I'm not exactly sure what advice you're seeking but I rigged many of the 2D characters in the first Boss Baby series and a lot of them had pointy joints. You can see some of this on my 2020 reel starting at around 1:18. Maybe the following tips will help...

The arms and legs are mostly rigged using point binding. In the actions for the elbow and knee Smart Bone, frame 1 is a smooth point on both sides of the limb and it becomes a peak point almost immediately. That's really all that's going on in there. Since both sides are 'pointy' by design, this was straightforward to setup.

Victor Paredes rigged some of the characters for us and he introduced a useful technique for animating the joint folds. In our original setups, the arms were a single shape but duplicated with upper and lower regions filled differently in each duplicate; this allowed us to easily 'wrap' the limb around the torso and keep the arms looking like a seamless shape--this is a fairly typical setup when using vector art. Victor's addition was to drag the elbow point for the overlapping limb section across the lower layer limb section to create the fold. By changing the stacking order of the limb sections, the set up created a convincing fold to show the arm pointing towards camera or facing way with minimal animation.

The technique works nicely when you have pointy joints and it was much simpler than what I was doing, which was hiding using stroke exposure to extend the line and a separate SBD to change the fold direction for the limb z-angle. This technique may be less effective for characters with more realistic joints, but it was usually perfect for Boss Baby characters.

I think the most noticeable example of this technique on my reel can be seen in the terminator-theme version of Timmy (animated by Tyler Melee.) It's even more noticeable in the space-theme versions of the parents which were rigged by Victor. This footage isn't on my reel but it can be seen in the show.