Touches without a single animation
Watch the clip above closely: nobody animated it. There is no "take hand" animation in the game, and no "pick up a mug from the floor" animation either. Both gestures are worked out while you watch.
How games usually do it
In a life sim, when two characters hug, kiss or hold hands, the game plays an animation made by an animator for exactly that pair of roles. The two characters are first moved to a planned position relative to each other, then the animation runs. The contact looks right only because someone lined it up by hand, for one body size.
That is why most games lock or narrow body sizes, ship several variants of the same kiss for different heights, or accept hands sinking into shoulders and arms passing through backs. Every new gesture means new animation work, for every combination it has to cover.
What Underlives does instead
A touch in Underlives is described, not animated: which hand, which place on the other person's body, how long to stay, what the hand does while it is there. When it happens, the game:
- finds the spot on the skin, not on the skeleton. It knows where that body's surface actually is, with its own shape, so a hand lands on a heavier shoulder or a slimmer waist the same way;
- chooses where to stand and how: stay put, step in, walk round, rise on tiptoe, crouch or kneel, whichever reaches with the least effort;
- moves the arm, the hand, the back and the head to get there, on top of whatever the body was already doing, so an idle keeps breathing under the touch;
- lets the other person answer: look back, return a hug, meet a hand or a kiss halfway.
The same machinery picks things up. In the clip, the man crouches, reaches and closes his fingers on a mug standing on the floor. Put the mug anywhere else and he will find another way to it.
Why it matters
Underlives is a city that lives without you: people have personalities, wants, relationships, and act on them whether you are there or not. A world like that cannot rely on a hand-made animation for every gesture between every two people. Gestures have to come out of the simulation itself, between any two bodies, anywhere.
It also means touches are mod content. A new gesture is a short text file (which zone, which hand, how long), with no animation to make. Modders already get the full list in the Touches documentation.
As far as we know, no other game computes a touch, a hug or a kiss on the actual bodies like this rather than playing a pre-made animation. If you know one, tell us on Discord: we would genuinely like to see it.
What's next
It is not finished. Some arms still bend oddly when two people stand very close, and we are working through the gestures one by one. We will keep posting clips here as it improves.