## Top-Down Recommendations

Official forum for the Chipmunk2D Physics Library.

### Top-Down Recommendations

Hello,

I am writing a game that is top-down rather than side-scrolling. Any recommendations on how to approach this with chipmunk? One issue that comes to mind is how to have the friction apply "sideways" rather than downward, etc. (There will be no "sideways" gravity, per se, as I will not be simulating "falling".)

Thanks for any insight y'all have to offer.

Dirk
dirkbj

Posts: 7
Joined: Wed Oct 03, 2007 11:56 am

### Re: Top-Down Recommendations

Now that I have had the chance to play with the framework, I can be a bit more detailed in my questions. Again, from a top-down perspective:

• How would I apply the shape.u and shape.surface_v to the forces and torque on a body?
• How can I create a "floor" upon which to "place" my bodies so that things like shape.u and shape.surface_v have something to act against?

Thanks for the help,

Dirk
dirkbj

Posts: 7
Joined: Wed Oct 03, 2007 11:56 am

### Re: Top-Down Recommendations

Sorry I haven't gotten back to you about this sooner.

I've thought about this as well for making a top down driving game. You can calculate the friction forces on the wheels easily enough and apply those to the body.

The problem is that the friction force won't quite have the stopping power that it should have unless it is made into a constraint that is solved along with the collisions and joints. This problem will really only show up in the case where you are pushing an object that should be held in place due to friction. Instead of staying put, it will slowly creep.

I've been thinking about doing away with joints in place of just generic constraints. (really just a name change) Constraints could include other things such as top down friction (for lack of a better term), damped springs done right, motors, etc.
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slembcke
Site Admin

Posts: 4164
Joined: Tue Aug 14, 2007 7:13 pm

### Re: Top-Down Recommendations

I would definitely like to see constraints, and it would be a great improvement in flexiblity.
altitudems

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Joined: Fri Nov 02, 2007 10:46 am

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