[Opensim-dev] Using ODE for vehicles and ragdolls

[Kyle "G"]

+1 Hurumph for Charles and Nlin we badly want to see our stationary monorail
come to life.
Kyle G
www.reactiongrid.com 
 
From: opensim-dev-bounces at lists.berlios.de
[mailto:opensim-dev-bounces at lists.berlios.de] On Behalf Of Charles Krinke
Sent: Tuesday, November 18, 2008 10:55 PM
To: opensim-dev at lists.berlios.de
Subject: Re: [Opensim-dev] Using ODE for vehicles and ragdolls
 
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)
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