[Opensim-dev] density

[Charles Krinke]

I'm not criticizing the mass of the avatar at all, but I am trying to look forward to a time when we could have different masses of prims and objects and go beyond what traditional secondlife is used to.

In thinking about that, I am hoping we could discuss how we might make a table or enum's of several materials such as shown in the client for rubber, glass, metal, stone and see some advantage in our use of physics for materials of differing densities and frictions.

Perhaps it may not matter what the avatar density is so much, as it might matter how we move forward in defining additional material properties for OpenSim that make use of the packet types already defined.

Charles




________________________________
From: Teravus Ovares <teravus at gmail.com>
To: opensim-dev at lists.berlios.de
Sent: Sunday, March 22, 2009 2:32:58 PM
Subject: Re: [Opensim-dev] density

A couple of points here

As far as LSL is concerned, mass is the same whether metal, rubber, glass,
rock or plywood from what I've been told.    There are other changes
though..  like bounciness.

The mass of the avatar has been the same since implementation and
works well with the Avatar PID controller in the ODEPlugin.   Changing
the avatar mass may make the Avatar PID controller malfunction as it
is.   Chances are it will need to be re-tuned for a lower mass (which
is what I /think/ you're syaing here)

Other comments?

Teravus

On 3/22/09, Charles Krinke <cfk at pacbell.net> wrote:
>
> We have m_density defined in two different places with two different values.
>
> One is in:
> ...\OpenSim\Region\Physics\OdePlugin\ODECharacter.cs - (72,
> 22) :
>
> public float m_density = 60f;
>
> Another is in:
> ...\OpenSim\Region\Physics\OdePlugin\ODEPrim.cs(152):
>
>
>  private float m_density = 10.000006836f; // Aluminum g/cm3;
>
> And in looking at the usage to calculate mass, it looks like the math is
> right, but yet, the avatar seems to have a higher density then the prim.
>
> I know that these are empirically determined, but in trying to look forward
> to a world where we actually might use the density of metal, rubber, glass,
> rock, plywood to do some additional physics *stuff*, it seems that we might
> want to see if we can harmonize our notion of density a little bit.
>
> Perhaps I am just missing the boat here. But, I would like to understand how
> we might be able to move forward a little bit on density some time.
>
> Charles
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>
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