2B Tickled in the Machine Breakdown (Patreon)
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First off want to say hello and thanks to all my new Patrons! Looks like we got a good influx from the tickling community, and I'm happy to have you here. While there will be a variety of stuff here, tickling will always be a core part. I'm still pretty darn early into this journey, so I'm excited to have you along for the ride.
Let's get into it!
This one was a bit of a monster to get through, as towards the end animating and keeping track of 12(!) tickling devices became cumbersome. Thankfully I had a goal in mind from the start, and relied on having everything blocked out and a clear plan of action.
The main challenge was to keep the tickling devices (mainly, the hands) in consistent contact with 2B's increasingly writhing body. To do this, I used over two dozen empties parented (with the Child-Of Constraint) to the various parts of 2B's body. I then parented the hands/devices to these empties, at varying levels of influence.

Having two constraints, one to the chest and one to the (tight!) tummy, both set to 50%, helped to keep the hand in consistent contact. At the end of the day, there's no real way to avoid some clean-up, which I ended up having to spend a considerable amount of time brute-forcing my way through.
For the actual grabbing of flesh, I used shapekeys. This was easy when the hand was stationary, but when the hand moves across the body (such as on the inner-thigh), the challenge became how to animate a "moving" shapekey, or at least create that illusion. Using the inner-thigh as an example, I ended up creating 3 vertex groups (loop selections on the thigh) and 1 shapekey duplicated 3 times, and then assigned to the vertex groups. So, I would select an edge along the inner thigh, pull it out a bit under a shapekey, duplicate this shapekey 3 times (giving me thigh.1.L, thigh.2.L, and thigh.3.L) and then assigning vertex groups to these shapekeys. This gave me some consistency in the deformation.

For the hands I ended up going with basic IK rigs. The foot scrubbers used a different method I learned about while making this video; "bone hooking." Using a curve aligned with the tubes of the foot controllers, I "hooked" the curve object points to bones, giving me the ability to animate them all squiggly like (select bone in pose mode, shift+select curve, tab into edit mode, select curve point, Ctrl+H "hook to selected bone").

My original plan was to use this same method for the hands, but I'm thankful I didn't, as while it represents a "tube" a bit better, it's very time consuming to animate, as every bone needs to be animated to be convincing. In the end, I got the best of both worlds (though I will continue to investigate methods for future tickling videos).
The set itself became a bit of an issue later on as render times began to increase. The "beams" that go all the way up (using an array+mirror modifier) became very memory intensive (adding a million+ faces when turned on). My solution was to do something I've never done before; animate the visibility on/off in accordance with the shot. This was a bit tedious to do, but it let me keep my render times under 20 seconds a frame (necessary when you have 6,000+ frames).
In looking at tickling reference video, I discovered that the face doesn't actually move that much when laughing. I wanted to have movement/dynamism in the face though, so I decided to focus on the lips, making sure they slid up/down convincingly, exposing the gum-line (which really sells the effect of painful laughter). I used this technique all throughout the video, increasing it towards the end.

I had a choice to make on this last shot of 2B being tickled. I had already animated most of the movement and then had the inclination to... put it out of focus. Normally I ere on the side of clarity, as no one wants this kind of work to get TOO artsy, or at least the art should support the purpose (S M U T). In this case, though, I figured I could give myself some leeway. I felt the shot being off-center and out of focus made it feel as if the machine is impartial to 2B's predicament, and that it will continue to go on-about it's business no matter how much noise and writhing the poor robot does. What's the term for this technique? It's, uh... (*googles it*) "Mise-en-scène."
https://en.wikipedia.org/wiki/Mise-en-sc%C3%A8ne


Finally, for this last shot where the building lowers into the ground, I really didn't want to parent everything to an empty (the rig, the building, the 12 tickle devices, etc). Not that it wouldn't work it just felt... finicky. So, I simply raised the whole landscape UP! With the camera parented to the land, I added two keyframes on the Z-axis. The best solutions are often the simplest.

I hope you enjoyed this video! Feel free to ask any more questions in the comments or on my Discord. I've been very happy with the response and again, welcome all the tickle lovers to this community.

Succubus Doms Elf is on the way, and I'll have another foot-club video out fairly soon (along with a loop at some point this month, when I need a break from the big animation).
Take care!