*Realistic* Physics for simulation

[ScorpionWasp]

1 - Is there an “easy” and performant way to calculate a sprite’s cross section in the direction it’s currently moving, for realistic air/water drag effects? You know, for emergent, organic air/watercraft properties such as max speed and fuel consumption.

2 - I notice that 3D physics materials have both static and dynamic friction variables, whereas 2D physics only have “friction”. That strikes me as a really odd design decision. Surely static and dynamic friction are equally relevant in 2D physics? What’s the rationale here? How should I go about implementing static friction in 2D?

3 - Is there a way to calculate what PERCENTAGE of a sprite is making contact with an effector? For example, a jumping whale that is still fully submerged will be subjected to different drag than one who has only the very tip of their tail still in the water.

[MelvMay]

@ScorpionWasp

I notice that 3D physics materials have both static and dynamic friction variables, whereas 2D physics only have “drag”. That strikes me as a really odd design decision. Surely static and dynamic friction are equally relevant in 2D physics? What’s the rationale here? How should I go about implementing static drag in 2D?

No design decision from Unity; we use Box2D and this is how it’s modelled whereas 3D use PhysX. We’ve exposed what’s available.

@ScorpionWasp

3 - Is there a way to calculate what PERCENTAGE of a sprite is making contact with an effector? For example, a jumping whale that is still fully submerged will be subjected to different drag than one who has only the very tip of their tail still in the water.

Why not use the effector to do that itself. There’s the AreaEffector2D and potentially the BouyancyEffector2D that may provide what you want.