[ODE] Ragdoll performance with OpenDE

[Mohsin Hasan]

Noley,

Exactly this happened to me when I started my simulation. In my case it was
a wrong parameter to the function dJointCreate* that was causing the
problem.

I was passing the collision space to the function (as shown below) and it
was causing my joints to collapse

dJointCreateHinge (world.id(), collisionSpace);

Replacing the above call with 

dJointCreateHinge (world.id(), 0);

solved the issue though I am still unclear why it is the case. I will try to
look into this once I have some time.

Let me know if this fixed your problem.

Regards,
Mohsin

-----Original Message-----
From: ode-bounces at q12.org [mailto:ode-bounces at q12.org] On Behalf Of Noley
Edge
Sent: Tuesday, January 13, 2004 10:31 PM
To: ode at q12.org
Subject: Re: [ODE] Ragdoll performance with OpenDE

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.


--Noley


------------------------------------------------------

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>
Message-ID:
<008201c3d9a4$54df7360$6a01c80a at trivor.com>
Content-Type: text/plain;	charset="US-ASCII"

Hi,

I'm new to OpenDE. I've done some work with Tokamak
but I really like 
the
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 
seems
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 
haven't
done anything fancy yet, just added simple hinge
joints. ODE is built 
in
single precision mode, MAX_CONTACT points for
collision is only 3 and I 
am
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 
hiccups. 

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

Regards,
Mohsin


-----------------



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