"Swimming" Physics with Rigidbodies

Question

I've always been stumped when it comes to this question. The best reference I can say is that I want to replicate a swimming physics setup like in Super Mario 64 (1996, Nintendo 64 title for those devs that go "uh?").

In Mario 64's implementation, there's two things I can see - one, the gravity changes to a more "slower" pull down rather than the on-land gravity, and when you press A to swim it applies some upwards momentum, as well as the direction you're traveling - so you end up going forwards on the Z axis Mario's facing (so to speak) and also a little up on the Y axis.

Unlike previous attempts where I killed gravity all together and I'm not doing that again because it caused my character's setup to do barrel rolls, I'm unsure how I would implement it.

I was wondering if anyone had any ideas on how to do underwater physics. I could use Character Controller and manually do gravity, but I perfer to use Rigidbody where possible (as it allows for more dynamic forces, etc). Do I tweak the gravity?

I do apologise for having no code, but I'm just collecting some implementation ideas before I put the pencil to the IDE.

Cheers!

Answer 1

Best Answer

Answer by FirePlantGames · Jul 07, 2015 at 12:53 AM

Well. Irrelevant note, but I'm pretty sure every dev knows what you're talking about when you mention SM64. But on topic; I think the best concept is to death the gravity and but keep friction. I don't have code to show for this, but since you didn't provide any, I am not obligated to either :P But that concept is probably your best bet, as this is essentially what SM64 water physics does.

Add comment · Show 6 · Share

MCoburn · Jul 07, 2015 at 12:57 AM 0

Share

So, i would lower the gravity "pull" (I think the default is like -9.81 in Unity3D physics) to say half that? Seems like a reasonable experiement.

FirePlantGames · Jul 07, 2015 at 01:40 AM 0

Share

Yep. But also add enough force "upwards" (On a global scale) to keep the consistent falling from pulling to fast and not like your underwater at all.

darkhog · Jul 07, 2015 at 01:40 AM 1

Share

That, or just increase rigidbody's drag.

FirePlantGames · Jul 08, 2015 at 02:32 AM 0

Share

Sure you cooould do that if you want to be logical and easy about it.

kingcoyote · Jul 08, 2015 at 07:22 PM 0

Share

I would highly recommend not changing the gravity from -9.81. Ins$$anonymous$$d, change the rigidbody's gravity scale from 1 to something like 0.25. If you change the global gravity setting, than anything that is above water will also act like it's under water.

$$anonymous$$aybe set the entire water surface as a trigger. When entering the water, set gravity to 0.25. When exiting the water, set gravity back to 1.

Show more comments

Answer 2

Answer by MCoburn · Jul 08, 2015 at 03:28 AM

Alright, so what I did was increase the drag on the character, to cause it to slow down. So the winner is memorymod with a bonus point to darkhog.

Now... time to implement this with the controller scripts...

Thanks for the help, I appreciate it.

Add comment · Show 1 · Share

FirePlantGames · Jul 08, 2015 at 07:13 PM 0

Share

no problem!

"Swimming" Physics with Rigidbodies

2 Replies

Your answer

Welcome to Unity Answers

Follow this Question

Related Questions