[x3d-public] X3D minutes 11 FEB 2022: , X3D4 Particle Systems component review, adding enabled field to X3DParticleEmitterNode ?

Thu Feb 17 01:48:44 PST 2022

John, thanks for looking ahead.  The best way to think through notional use
cases is by, ahem, using them - demonstrating with examples.  We do need
shared example scenes in our archives for this component.

We remain at the editorial stage of final review.  So we are not
re-inventing now.

When we can clarify the X3D4 specification, we are doing so.  If our current
final review leads proposals for future X3D4.1 spec, we add them to Mantis.
Onward we go.

all the best, Don

-- 

Don Brutzman  Naval Postgraduate School, Code USW/Br        brutzman at nps.edu

Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA    +1.831.656.2149

X3D graphics, virtual worlds, Navy robotics https://
faculty.nps.edu/brutzman

From: John Carlson <yottzumm at gmail.com> 
Sent: Friday, February 11, 2022 10:55 AM
To: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
Cc: X3D Public Mailing List (x3d-public at web3d.org) <x3d-public at web3d.org>
Subject: Re: [x3d-public] X3D minutes 11 FEB 2022: , X3D4 Particle Systems
component review, adding enabled field to X3DParticleEmitterNode ?

I think it would be better to offer a transition from enabled to disabled
and back.   But perhaps that's max speed and min speed?

But I agree that enabled is a good start, and adding a field for full on and
full off with no transition is a good idea.   One might think of scenes
where a door is shut.

I'm not sure if full on/full off matches physical reality.   I can think of
examples like bombs, volcanoes and dropping things though.

A combination of min/max speed and on/off would cover the cases I'm thinking
of.

John 

On Fri, Feb 11, 2022 at 12:36 PM Brutzman, Donald (Don) (CIV)
<brutzman at nps.edu <mailto:brutzman at nps.edu> > wrote:

Tweeted:

*	X3D meeting minutes 11 FEB 2022: #X3D4 Architecture Particle Systems
component review.  Community question: is it OK to add 'enabled' field to
all emitter nodes, providing simpler animation control by authors and end
users?
*	https://twitter.com/Web3DConsortium/status/1492205445120815105
<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Ftwitter.c
om%2FWeb3DConsortium%2Fstatus%2F1492205445120815105&data=04%7C01%7Cbrutzman%
40nps.edu%7Cdf587868e4dc45076d8808d9ed8ff681%7C6d936231a51740ea9199f75789633
78e%7C0%7C0%7C637805869539926559%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDA
iLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=IyApkG4TB7hbt%2
FYIPSGiNjOhs4LpScFDdOr5MDPrrHE%3D&reserved=0> 

Request: if anyone has links or screenshots of Particle System models in
X3D4, we are happy to share them publicly. Thanks in advance for all posts.

all the best, Don

-- 

Don Brutzman  Naval Postgraduate School, Code USW/Br        brutzman at nps.edu
<mailto:brutzman at nps.edu> 

Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA    +1.831.656.2149

X3D graphics, virtual worlds, Navy robotics https://
faculty.nps.edu/brutzman <http://faculty.nps.edu/brutzman> 

From: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu
<mailto:brutzman at nps.edu> > 
Sent: Friday, February 11, 2022 9:28 AM
To: X3D Public Mailing List (x3d-public at web3d.org
<mailto:x3d-public at web3d.org> ) <x3d-public at web3d.org
<mailto:x3d-public at web3d.org> >
Cc: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu <mailto:brutzman at nps.edu>
>
Subject: X3D minutes 11 FEB 2022: , X3D4 Particle Systems component review,
adding enabled field to X3DParticleEmitterNode ?

Attendees: Anita Havele, Vince Marchetti, Dick Puk, Don Brutzman.  Regrets:
Nicholas Polys, John Carlson.

1.	Completed X3D4 Particle Systems component review.  All Mantis issues
updated and resolved.  Latest modifications highlighted via CSS with
corresponding Mantis issues documented using /title/ attributes.

*	X3D4 Architecture, clause 37 Particle Systems component
*
https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/
components/particleSystems.html 

a. Improved issue notes, WindPhysicsModel:

*	Mantis 464: 40.4.10 WindPhysicsModel - Question on Speed 
*	https://www.web3d.org/member-only/mantis/view.php?id=464
*	Related issue: Mantis 768.  Deferred to X3D 4.1

Likely pressure equation for future use will be based on difference between
particle speed and wind speed.

Note that the turbulence definition (regarding variability of wind
direction) also needs improvement. For example, can highly turbulent wind
stop or reverse direction?

b. New deficiency noted: how do you turn off an emitter node?

No /enabled/ field is present.  Possibly /speed/ might be zero, but then
particle geometry would still be present and perhaps pulsing...  Possibly a
Switch node might hide it, but then the browser writer likely just turns it
off anyway to save computational resources, which is functionally equivalent
to enabled FALSE.

We discussed in some depth. Have raises an issue in Mantis, here posted
publicly.  We seek comment, and decide (hopefully next week) whether it is
something to be accomplished in X3D 4.0 or else deferred to X3D 4.1. 

*	Mantis 1380: ability to disable/enable X3DParticleEmitterNode 
*	https://www.web3d.org/member-only/mantis/view_all_bug_page.php

Authors are unable to easily turn particle emitter nodes on or off.

X3DParticleEmitterNode (and implementing nodes) need field:

   SFBool [in out] enabled TRUE

Implementation is simple for browsers. This field has no impact on legacy
content.

Current workarounds:
* Possibly /speed/ might be zero, but then a particle would still be present
and pulsing...
* Possibly a Switch node might hide the emitter, but then the browser writer
likely turns it off anyway to save computational resources, which is
functionally equivalent to enabled FALSE.

Of related note: X3DParticlePhysicsModelNode in this component does include
an enabled field, for identical purposes.

Vince discussed his Browser Review document noting X3D support, we hope to
look at this draft further next week.

No member-only information included on this page.

Hope everybody has another great week.  Have fun with X3D!

all the best, Don

-- 

Don Brutzman  Naval Postgraduate School, Code USW/Br        brutzman at nps.edu
<mailto:brutzman at nps.edu> 

Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA    +1.831.656.2149

X3D graphics, virtual worlds, Navy robotics https://
faculty.nps.edu/brutzman <http://faculty.nps.edu/brutzman> 

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