[Opensim-dev] Using ODE for vehicles and ragdolls

[Charles Krinke]

Dear Nlin:

This interests me also. Perhaps we can discuss and collaborate with others. Most of the hooks to get to ODE from scripts exist and we can extend and improve them as appropriate.

The part I am currently puzzled about is physical prim interactions. I am trying to understand the simple case of a ring over a pole or its inverse, a ball in a tube. 

In both cases, we seem to have the tendency for the two prims that are interacting to interpenetrate and the forces then fling them apart like they are spring loaded. 

Calming down the simple two-prim interaction case might go a long ways towards being able to build a train or a monorail, which is one of the projects that is currently on my list.

Charles




________________________________
From: nlin (message) <nlin.message at gmail.com>
To: opensim-dev at lists.berlios.de
Sent: Tuesday, November 18, 2008 6:11:08 PM
Subject: [Opensim-dev] Using ODE for vehicles and ragdolls

Hello,

There's been some discussion about SL-compatible vehicles in OpenSim recently, with its higher-level abstraction of how vehicles work. This would have the long-term goals of compatibility and ability to swap out physics engines while still using the same vehicle layer.

SL-compatibility and abstracting vehicles from the physics engine are good goals for the long term; sort of a top-down approach (start with the vehicle abstraction, map it to many different physics engines).

Complementary to this, I'd like to explore and start discussion of an alternative way of handling vehicles by using a bottom-up approach. Starting with the specific physics engine of ODE, can we use ODE-specific features to make simple vehicles? 

I did some experiments with OpenSim and ODE and the answer seems to be yes, we can make simple vehicles with ODE by using joints. We can also make ragdolls. I posted some videos to YouTube of the preliminary results:

http://www.youtube.com/watch?v=iYIh-eIwmjs
http://www.youtube.com/watch?v=z9bedzIuxdM

This is only prototype work for now, put together sort of quickly as a proof-of-concept with just enough "plumbing" (data flow) to work. There are a number of issues that need to be solved for this to work cleanly. As far as I know (please correct me if I'm wrong) there hasn't been much work done to try to get ODE joints/vehicles/ragdolls working in OpenSim, but I think it's an avenue worth exploring.

Is there interest in pursuing this approach for OpenSim vehicles? I would look forward to discussing some of the issues that would need to be solved.

Thanks,
N Lin (nlin)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://opensimulator.org/pipermail/opensim-dev/attachments/20081118/c8c6d95d/attachment-0001.html>