[ODE] Ragdoll performance with OpenDE

Noley Edge noleyedge at yahoo.com
Tue Jan 13 09:30:50 MST 2004

I am attempting to do something similar and have run
into problems that I have posted here previously. I
have defined joints - hinge and ball type. My ragdolls
collapse to the ground when the simulation begins. 
Also, when my ragdoll collidies with anything the
geomtries come apart and are jetisoned off to
neverland. I can't seem to keep the "ball in the
socket" or the hinges "together".  Very frustrating.

Can you give me some examples of the parameters that
you defined for your joints (axis, anchor, erp,
cfm,lowstop, histop, etc.)?  

Are all of the geometries for a ragdoll in a single
space? Single joint group?

Do you have to do anything manually to maintain the
joints after collision?  

Any help is greatly appreciated.



Date: Tue, 13 Jan 2004 12:10:31 +0500
From: "Mohsin Hasan" <mohsin.hasan at trivor.com>
Subject: [ODE] Ragdoll performance with OpenDE
To: <ode at q12.org>
<008201c3d9a4$54df7360$6a01c80a at trivor.com>
Content-Type: text/plain;	charset="US-ASCII"


I'm new to OpenDE. I've done some work with Tokamak
but I really like 
feature set offered by ODE so I thought of switching
to ODE. I tried to
implement a Ragdoll demo with ODE with 10 Bones (9
joints). The demo 
to work fine. The only issue I have is performance. I
mean I create 5
Ragdolls and the performance of the simulation starts
to stall. I 
done anything fancy yet, just added simple hinge
joints. ODE is built 
single precision mode, MAX_CONTACT points for
collision is only 3 and I 
using dWorldStepFast1 method with only 8 iterations to
get extra bit of
speed but nothing seems to help. On the other hand my
Tokamak demo can
easily manage 40 Ragdolls (same configuration) without
any major 

My question is. Is ODE not suitable to implement
Ragdoll or commercial
quality game physics yet due to speed constraints? Is
there anything 
done to increase the performance? I know there are a
few experimental
functions to auto disable bodies like in Tokamak but
this will only 
once a body is in a resting state. If most of the
objects (Ragdolls) 
moving (falling) speed is just unbearably slow.



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