Help Aerodynamics for non cloth

[josemendez]

No I'm not confusing it with inertia.

For games you somtimes want to exaggerate the physics a bit, especially if you run fast in this case to get the feeling of motion.

I think you are wrong in your statement "While running at a constant speed (no acceleration), the ears would be completely still.".

Hi,

I was talking about inertial forces when stating that: if you’re on a car moving at a steady 100 km/h, you don’t feel any forces acting upon you: only if you suddenly accelerate or brake. This is the same thing that happens to actors inside a moving solver in Obi.

Obviously if you factor aerodynamics in, or any kind of external drag force proportional to velocity then then there’s a force being applied: the force you’d feel while A) stationary inside a gust of 20 km/h wind and B) running at 20 km/h with no wind is the same. I was simply pointing out that ears of any kind (or any other body appendage) aren’t light enough for aerodynamics to normally have any effect on them, but I understand you might want to greatly exaggerate its effect. In order for this to work in Obi, actors have to move relative to the solver.

This is not what experiencing when moving my attached transform with a rope that has small mass and high air drag coefficient, once I add a bit of wind through solver it moves a lot though.

I’m unable to reproduce this: moving a rope in absence of wind with high drag does have a noticeable effect. Make sure the transform you’re moving is not the solver itself, as that will move the rope as well while excluding world-space velocity effects. Could you share a video of this?

Nevertheless, note that in the case of a character you’ll need to take the solver out of its hierarchy and keep it static (that is, perform the simulation in world space) for this to work, otherwise particles won’t have any velocity relative to the solver and aerodynamics won’t have any effect.

If this is an inconvenience in your case, I can add a option to consider the solver’s velocity when calculating the relative velocity during aerodynamics. This would allow aerodynamics to work in absence of wind even when particles are not moving at all relative to the solver.

Kind regards,