Physics stuff

[Tesselode]

OK, so I want to have a platform that isn't affected by gravity or other objects that can be rotated and can push a ball around. I tried using a static object for the platform and using body:setAngle, but then the ball can get stuck in or go through the platform and the platform doesn't apply any force to the ball. How do you think I should do this?

[Robin]

I think you should use Joints for that. Not sure how. (I don't have that much experience with Joints.)

[kikito]

A platform that isn't affected by gravity or other objects that can be rotated and can push a ball around

I'd really like to help you, but you need to be more specific. If the platform isn't supposed to affect other objects, how is it going to affect a ball, which is another object?

You mention that you want to change the angle of the platform. Do you need it to spin around a corner, or around its center of mass? What's its shape? Where is it in relation to the ground?

If you don't feel like answering all this, a simple image (i.e. ms paint) would suffice.

But yeah, almost certainly you will want to use a revoluteJoint.

[Robin]

Now that I think of it, LovelyBigPlanet has “floating platforms”, which have a very high level of friction, but are not static. Probably not what you're looking for, though.

[rhezalouis]

Something like this?

screenCapture

rotatingPlatform.png (2.28 KiB) Viewed 2849 times

[Robin]

That.

[Tesselode]

Pretty much, except the ball shouldn't be able to push the platform. I think that today I'll post what I had that was sort of working.

[Robin]

except the ball shouldn't be able to push the platform.

Then you need to make the platform super heavy.

[Tesselode]

except the ball shouldn't be able to push the platform.

Then you need to make the platform super heavy.

Well, that would just lessen the problem, not fix it.

Is there a way to do this with a static body for the platform?

[Robin]

Is there a way to do this with a static body for the platform?

Well, there's the rub: if it is static, it can't rotate.

Making it very heavy means that no other object has any noticeable influence on it. Isn't that good enough?