# Physics Air Resistance: is this Chipmunk's global viscous damping?

• I'm a little miffed that Air Resistance influences rotation as well as movement. I would think it should only influence movement, and a different counter force (something against rotation) should have influence over rotation.

Is the Air Resistance setting this [quote from Chipmunk docs]:

(cpFloat) damping
Global viscous damping value to use for all rigid bodies in this space (default value is 1.0 which disables damping).

This value is the fraction of velocity a body should have after 1 second. A value of 0.9 would mean that each second, a body would have 80% of the velocity it had the previous second.

• @Deeeds No. Air resistance in real life slows down both motion and rotation, as should hyperPad air resistance.

• @Aidan-Oxley Objects don't have the same response to air resistance in their rotation as they do in their movement for various reasons.

Here's the two most important reasons:

1. weight distribution, think of a tire with no weight on the rim versus one with all weight on the rim
2. shape aerodynamics favouring either movement of the whole or rotation

• @Deeeds Doesn’t matter, as long as air resistance exists, no object will spin or move forever. I can though see how this could be useful for game making.

• @Aidan-Oxley EXACTLY!!

It makes things MUCH easier (and way more fun) to have air resistance on movement and rotation be seperate for all the good stuff.

There isn't the same drag on rotation on a ball spinning, for example, as there is on it moving.

And I think Chipmunk is the finest point of hyperPad. Its strongest, in fact. So it's a shame to not fully exploit its greatness.

List of hyperPad Best in Class features...

1. Physics Engine is Chipmunk... best in class (but not fully utilised)

3. Fast build and test time

Worst missing feature?

1. No UNDO in Behaviours and No UNDO after play testing

The above is strong enough to be points 1 through 5...

1. No Selection of Multiple Behaviours for Copy/Paste, Sharing, Grouping, Collapsing and Function Creation

The above is the rest of the points through to 10...

1. No drawing abilities, whatsoever (all art needs to be created and/or imported)
This one is weird because they recognised the need for unique sounds by putting in a little noise maker, but have zero drawing facilities.
2. Physic editor is rubbish, and this problem directly related to the above point.

etc...

• @Deeeds What game/app maker did you come from before trying out hyperPad? You complain about a lot of stuff hyperPad lacks lol. You can create air resistance that affects only motion manually.

• @Aidan-Oxley This is just observations. Not yet complaints.

I've varying experience with a few engines.

I don't have a favourite. Maybe Unreal Engine, but that's for different stuff. Not lightweight little 2D experiments.

Why do you try so hard to defend the current state of this app?

• @Deeeds I like hyperPad and I understand that they are a small team.

• @Aidan-Oxley It's only going to get a better team if they make the app better.

And making it better... there's a LOT of low hanging fruit on that tree.

• @Deeeds honestly I rather enjoy finding creative ways to work around the limitations of coding on an iPad app, which is why I spend more time building more difficult concepts than making actual games! Lol

• @iTap-Development I enjoy finished things. And finishing things.