EDIT: I've removed some vagueness and replaced it with more of a description of the intended use case.
I'm looking for some suggestions for ways to infer what the player's "forward" vector is in a room-scale 360 experience. I'm not currently worried about extreme edge cases, especially if it sounds like the user may be intentionally not doing the intended thing, but I am interested in getting a decently accurate forward vector when they could be looking or facing any direction. I also don't care about "upness" or magnitude of the vector, so it'll end up being projected onto the (Unity's) X/Z plane and normalized.
I'm exploring the idea of punching as a means for locomotion. The player should move in the direction that they punch, which in itself I feel is an easy solve. The problem is, much like the problem of arm-swing movement, it is very hard and unnatural to punch exactly straight forward. People tend to punch at least a little across their body. This causes the player to weave back and forth through the world, like some sort of drunken master. I don't like the idea of using the headset's forward vector either. I want the player to be able to look around while playing; I feel it is an integral part of the experience to be able to look ahead one punch and plan the next move.
It's also important that sensor set up and room orientation should not be taken into account. I'm looking for something that could work in a large space with 360 tracking.
- Grabbing an average position of the hands, getting the vector from the head to this new position. This is where I've spent most of my time, I think. I've tried a weighted average, where hand position gets more or less weight depending on distance from head. In practice, this ends up exacerbating the problem
- Grabbing the vector from the head to the dominant hand
- Dropping a raycast to the floor and using the hit geometry's forward vector
- Getting a complicated IK rig setup, potentially hiding the geometry, and using the rig's hip placement/orientation to infer "forward"
None of these quite feel right to me, although the average-hand-position vector feels the right-est.
Is this a solved problem that I'm just not searching hard enough for? Anybody else have interesting solutions to this problem? Am I being too vague and should really just seek out a solution for a much more specific use-case and be happy with that?