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<div class="moz-cite-prefix">Dave,<br>
<br>
Do you have a particular open-source physics engine that you like?
Have you done any work in trying to integrate one into an X3D
scene? We would really like your input and expertise here.<br>
<br>
Thanks,<br>
<br>
Leonard Daly<br>
<br>
<br>
<br>
<br>
</div>
<blockquote cite="mid:553ACB55.5030406@realmofconcepts.com"
type="cite">This has been a bother for me since I got into x3d in
2003.
<br>
<br>
Follow me! @thatvrguy
<br>
<br>
On 4/24/2015 2:57 PM, Christoph Valentin wrote:
<br>
<blockquote type="cite">Hi Dave,
<br>
I believe, X3DOM has done that and I believe a lot of open
and/or closed source game engines have done that. No doubt.
<br>
The point is, to have it in an ISO standard on a high layer of
scene description (i.e. X3D/VRML).
<br>
All the best
<br>
<br>
Gesendet: Freitag, 24. April 2015 um 19:18 Uhr
<br>
Von: "Dave A" <a class="moz-txt-link-rfc2396E" href="mailto:dave@realmofconcepts.com"><dave@realmofconcepts.com></a>
<br>
An: "Christoph Valentin" <a class="moz-txt-link-rfc2396E" href="mailto:christoph.valentin@gmx.at"><christoph.valentin@gmx.at></a>,
<a class="moz-txt-link-abbreviated" href="mailto:x3d-public@3dnpvei.com">x3d-public@3dnpvei.com</a>, "Roy Walmsley"
<a class="moz-txt-link-rfc2396E" href="mailto:roy.walmsley@ntlworld.com"><roy.walmsley@ntlworld.com></a>
<br>
Cc: <a class="moz-txt-link-abbreviated" href="mailto:x3d-public@web3d.org">x3d-public@web3d.org</a>
<br>
Betreff: Re: [x3d-public] Gravity Sensor?
<br>
I think what you are asking for is a Physics Engine. Has one
been
<br>
integrated yet? It really needs it.
<br>
I think x3dom glued one in somehow.
<br>
Dave Arendash
<br>
<br>
On 4/24/2015 7:16 AM, Christoph Valentin wrote:
<br>
<blockquote type="cite">Thanks Lauren and Roy,
<br>
<br>
My question was from a theoretical perspective (maybe I will
do some trials with GeoSpatial component soon).
<br>
<br>
Thinking about railway cars, that contain scenery and avatar
can enter. --> need superposition of gravity and inertial
forces (from the acceleration of the railway car).
<br>
<br>
KR
<br>
<br>
<br>
<br>
Gesendet: Freitag, 24. April 2015 um 14:12 Uhr
<br>
Von: GLG <a class="moz-txt-link-rfc2396E" href="mailto:x3d-public@3dnpvei.com"><x3d-public@3dnpvei.com></a>
<br>
An: <a class="moz-txt-link-abbreviated" href="mailto:x3d-public@web3d.org">x3d-public@web3d.org</a>
<br>
Betreff: Re: [x3d-public] Gravity Sensor?
<br>
Yes there's ParticleSystems (thanks Roy), maybe the
<br>
X3DParticlePhysicsModelNode in particular is what you're
looking for, or the
<br>
X3DParticlePhysicsModelNode. Cheers, Lauren
<br>
<br>
<br>
40.4.4 ForcePhysicsModel
<br>
<br>
GravityPhysicsModel : X3DParticlePhysicsModelNode {
<br>
SFBool [in,out] enabled TRUE
<br>
SFVec3f [in,out] force 0 -9.8 0 (∞,∞)
<br>
SFNode [in,out] metadata NULL [X3DMetadataObject]
<br>
}
<br>
The ForcePhysicsModel node specifies a physics model that
applies a constant
<br>
force value to the particles. Force may act in any given
direction vector at
<br>
any strength.
<br>
<br>
The force field is used to indicate the strength and direction
of the force
<br>
(e.g., gravity) that should be applied. Force is specified in
metres per
<br>
seconds-squared (m/s2). If the particles are defined to have
zero mass by
<br>
the emitter, the ForcePhysicsModel node has no effect.
<br>
<br>
<br>
40.4.1 BoundedPhysicsModel
<br>
<br>
BoundedPhysicsModel : X3DParticlePhysicsModelNode {
<br>
SFBool [in,out] enabled TRUE
<br>
SFNode [in,out] geometry NULL [X3DGeometryNode]
<br>
SFNode [in,out] metadata NULL [X3DMetadataObject]
<br>
}
<br>
The BoundedPhysicsModel node specifies a physics model that
applies a
<br>
user-defined set of geometrical bounds to the particles.
<br>
<br>
The geometry field specifies a piece of geometry that models
the bounds that
<br>
constrain the location of the particles. When a particle
touches the surface
<br>
of the bounds, it is reflected. The particles may be
restricted to an inside
<br>
location or an outside location. All geometry defined by the
bounds are
<br>
considered to be non-solid, regardless of the setting of the
solid field. It
<br>
does not matter whether the particle impacts the front or back
side of the
<br>
geometry. Particles are reflected at the same angle to the
normal of the
<br>
surface to which they impact, continuing in the same
direction. The
<br>
calculation of the correct normal is determined by the rules
of the geometry
<br>
that forms the bounds.
<br>
<br>
EXAMPLE A particle can be made to bounce off an elevation grid
representing
<br>
terrain.
<br>
<br>
<br>
<a class="moz-txt-link-freetext" href="http://www.web3d.org/documents/specifications/19775-1/V3.2/Part01/components">http://www.web3d.org/documents/specifications/19775-1/V3.2/Part01/components</a>
<br>
/particle_systems.html
<br>
<br>
<br>
<br>
<br>
-----Original Message-----
<br>
From: x3d-public [<a class="moz-txt-link-freetext" href="mailto:x3d-public-bounces@web3d.org">mailto:x3d-public-bounces@web3d.org</a>] On
Behalf Of Roy
<br>
Walmsley
<br>
Sent: Friday, April 24, 2015 5:31 AM
<br>
To: 'Christoph Valentin'; 'X3D Graphics public mailing list'
<br>
Subject: Re: [x3d-public] Gravity Sensor?
<br>
<br>
Christoph,
<br>
<br>
In X3D the only place where forces, including gravity, can be
included is in
<br>
the Particle systems component.
<br>
<br>
There isn't anything like a "gravity sensor". You have to take
care of it
<br>
yourself. This could be done using external code and
interacting through the
<br>
SAI. Alternatively, you could use a Script node to keep
everything internal
<br>
to the scene.
<br>
<br>
>From your reasoning point d) I am assuming you are working
with the
<br>
GeoSpatial component. What sort of things do you want to apply
gravity to?
<br>
<br>
Roy
<br>
<br>
-----Original Message-----
<br>
From: x3d-public [<a class="moz-txt-link-freetext" href="mailto:x3d-public-bounces@web3d.org">mailto:x3d-public-bounces@web3d.org</a>] On
Behalf Of
<br>
Christoph Valentin
<br>
Sent: 24 April 2015 10:04
<br>
To: X3D Graphics public mailing list
<br>
Subject: [x3d-public] Gravity Sensor?
<br>
<br>
A few questions to the community.
<br>
<br>
Is there something like a "gravity sensor" in X3D/VRML?
<br>
<br>
Reasoning:
<br>
<br>
a) The Web3D Browser cares for gravity and collision
detection, when
<br>
controlling the movement of the avatar.
<br>
b) However, when controlling the dynamics of an arbitrary
object, I have to
<br>
care for gravity and collision myself
<br>
c) In classical scenes, the gravity is 9.81 m.s^-2 in -y
direction, no
<br>
problem
<br>
d) But how to calculate gravity in an X3D-Earth scene? Don't
we need a kind
<br>
of "gravity sensor" here?
<br>
<br>
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</blockquote>
--
<br>
Follow me! @thatvrguy
<br>
<br>
</blockquote>
<br>
<br>
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<br>
<br>
<div class="moz-signature">-- <br>
<font class="tahoma,arial,helvetica san serif" color="#333366">
<font size="+1"><b>Leonard Daly</b></font><br>
X3D Co-Chair<br>
Cloud Consultant<br>
President, Daly Realism - <i>Creating the Future</i>
</font></div>
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