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Change in Collisions Behavior between FS 1.0 and 2.0?

Nov 21, 2008 at 1:11 AM
Hi Guys,

Nice work with version 2.0, I like the refactoring I've seen so far!

I'm seeing different behavior in collisions though, and I'm wondering if anyone has some suggestions? Basically, I'm seeing tunneling and geometries passing through each other more often in 2.0 than in 1.0.

Here is an example...

If you check out this version 1.0 Rag Doll demo, you'll see there are very few tuneling problems:

But if you check out the port of the above demo to Farseer 2.0, you'll see the tunneling is quite frequent, and the poor rag doll gets stuck quite quick:

I checked that my GeomFactory.Instance.GridCellSizeAABBFactor is 0.1 in both demos, and nothing has changed except the port.

Thanks for any ideas!

Nov 21, 2008 at 11:31 AM
Are you 100% sure that it's relaive to 2.0? I'm asking because I've not noticed any problems of this kind. Could you edit one of our samples to demonstrate the problem and write it here? (or send it to me)

I can't seem to reproduce the problem unless I use really high velocities.
Nov 21, 2008 at 12:57 PM
Here are the steps I took and what I am seeing...

The demo I have here was created using FS 1.0 and doesn't have many issues with tunneling:

The only thing I did with this code is (1) change assembly reference from Farseer 1.0 to Farseer 2.0 and (2) correct any compilation errors due to Namespace changes.

But the end result is more tunneling problems, as you can see at

I tried lowering GridCellSizeAABBFactor, but it doesn't seem to help. I tried lowering my timeframe (I originally had Simulator.Update(.02f)) - that seems to help a little with the tunneling, but slows things down too much.

Nov 21, 2008 at 1:01 PM
Hmm... What version of 1.0 is it?

I'll need a sample project with the error in it. Could you provide me with the source code?
I will take a look at it.