OK, people, imagine this.....
My primary occupation is a sparktester.  A sparktester uses a high speed
hand held grinder with a 2-1/2" abrasive wheel to "sparktest" steel to
determine the approximate percentage of the chemical elements (carbon,
phosphurous, sulphur, silicon, moly, vanadium, & others) that make up the
steel alloy.  The various elements burst in unique shapes in the the spark
stream emitted from the contact....I swear!

We have never been able to adequately photograph these tests for published
training manuals.  I know what they look like, and I would like to see if it
can be described by ray tracing (Pov-Ray 3.1)

Can someone give me a start in the right direction? I would like to dipict
only the wheel and the spark stream which is emitted from the contact with a
particular grade of steel.  Any help in getting off the ground here would be
appreciated.

Thanks,
Dennis A. Smith
dsm### [at] netnitconet

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Should be a simple matter of CSG (constructive solid geometry, fancy
term for shapes combined into various other shapes by means of additive,
subtractive, and combination of the two, modeling; excuse me if you
already knew that) and using appropriate high ambience (glowing)
textures.
Afraid you are probably going to at least have to start a script/render
to show something of what you intend though to get real good help on it.
Maybe not, you never know here.
I did a lot of pyrotechnics as a 14 year old boy so I know a bit about
what you mean. Phosphorous, sulfur, charcaol, and a whole lot of other
chemicals too numerous to mention, even silicon (ground, powdered
glass).
Nothing of sparktesting however :(
Colors and types of spark I can imagine based upon compositions and size
of the particles but that's been two dozen years since I "burned"
chemicals. Not the exact same thing I'm sure.
Really it sounds quite simple though, give a holler about need of
special shapes and someone will probably have an idea. Or the spark
stream effect, there's a include file (or is it executable?) somewhere
for doing that sort of thing, albeit probably not in the way you want.
Hopefully the grinder will get spinning soon enough for you.


"Dennis A. Smith" wrote:
> 
> OK, people, imagine this.....
> My primary occupation is a sparktester.  A sparktester uses a high speed
> hand held grinder with a 2-1/2" abrasive wheel to "sparktest" steel to
> determine the approximate percentage of the chemical elements (carbon,
> phosphurous, sulphur, silicon, moly, vanadium, & others) that make up the
> steel alloy.  The various elements burst in unique shapes in the the spark
> stream emitted from the contact....I swear!
> 
> We have never been able to adequately photograph these tests for published
> training manuals.  I know what they look like, and I would like to see if it
> can be described by ray tracing (Pov-Ray 3.1)
> 
> Can someone give me a start in the right direction? I would like to dipict
> only the wheel and the spark stream which is emitted from the contact with a
> particular grade of steel.  Any help in getting off the ground here would be
> appreciated.
> 
> Thanks,
> Dennis A. Smith
> dsm### [at] netnitconet

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.htm
 mailto:inv### [at] aolcom?PoV

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I found the "spark" maker here on my computer. Holler if you want it. I
couldn't find a url to it in the readme. The name is Stomps Spark
Generator if you want to try searching for it.
Never mind, found it:

 http://www.sky.net/~keystone/trace/spark.htm

But it looks like its not what I was thinking of, more of a lightning
maker instead.
I know there is another such thing, "sparker.inc" maybe? I've seen it
make that grinding wheel type spray of sparks, so it does exist. Perhaps
someone here will know.


Bob Hughes wrote:
> 
> Should be a simple matter of CSG (constructive solid geometry, fancy
> term for shapes combined into various other shapes by means of additive,
> subtractive, and combination of the two, modeling; excuse me if you
> already knew that) and using appropriate high ambience (glowing)
> textures.
> Afraid you are probably going to at least have to start a script/render
> to show something of what you intend though to get real good help on it.
> Maybe not, you never know here.
> I did a lot of pyrotechnics as a 14 year old boy so I know a bit about
> what you mean. Phosphorous, sulfur, charcaol, and a whole lot of other
> chemicals too numerous to mention, even silicon (ground, powdered
> glass).
> Nothing of sparktesting however :(
> Colors and types of spark I can imagine based upon compositions and size
> of the particles but that's been two dozen years since I "burned"
> chemicals. Not the exact same thing I'm sure.
> Really it sounds quite simple though, give a holler about need of
> special shapes and someone will probably have an idea. Or the spark
> stream effect, there's a include file (or is it executable?) somewhere
> for doing that sort of thing, albeit probably not in the way you want.
> Hopefully the grinder will get spinning soon enough for you.
> 
> "Dennis A. Smith" wrote:
> >
> > OK, people, imagine this.....
> > My primary occupation is a sparktester.  A sparktester uses a high speed
> > hand held grinder with a 2-1/2" abrasive wheel to "sparktest" steel to
> > determine the approximate percentage of the chemical elements (carbon,
> > phosphurous, sulphur, silicon, moly, vanadium, & others) that make up the
> > steel alloy.  The various elements burst in unique shapes in the the spark
> > stream emitted from the contact....I swear!
> >
> > We have never been able to adequately photograph these tests for published
> > training manuals.  I know what they look like, and I would like to see if it
> > can be described by ray tracing (Pov-Ray 3.1)
> >
> > Can someone give me a start in the right direction? I would like to dipict
> > only the wheel and the spark stream which is emitted from the contact with a
> > particular grade of steel.  Any help in getting off the ground here would be
> > appreciated.
> >
> > Thanks,
> > Dennis A. Smith
> > dsm### [at] netnitconet
> 
> --
>  omniVERSE: beyond the universe
>   http://members.aol.com/inversez/POVring.htm
>  mailto:inv### [at] aolcom?PoV

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/POVring.htm
 mailto:inv### [at] aolcom?PoV

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Bob Hughes wrote:

> But it looks like its not what I was thinking of, more of a lightning
> maker instead.
> I know there is another such thing, "sparker.inc" maybe? I've seen it
> make that grinding wheel type spray of sparks, so it does exist. Perhaps
> someone here will know.
 
Might be able to use one of the liquid spray plugins for this.
Colefax has one the might do the job but I have never tested the
file so know little of it's capablilities.

http://www.geocities.com/SiliconValley/Lakes/1434/

-- 
Ken Tyler

mailto://tylereng@pacbell.net

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Wow! I thought only scrap-heap-foraging-blacksmiths used spark testing on a
regular basis. But you say you do it as an occupation. I guess I just learned
something!

I've only had limited experience in this field (only to the extent of
differentiating between mild steel, driveshafts, and files). I could imagine
that this would be difficult to capture on film. At the same time, however, to
render an image that is not just a pretty picture, but conveys accurate info
would in my opinion take a some work as well. The one advantage you'd have is
(relative) complete control over the composition and lighting of your picture.
As such, my humble suggestions would be:
	1. If you haven't used POV (or whichever renderer you choose) expect to
invest some time in familiarizing yourself with the program.
	2. Lay out exactly what you want to depict (e.g.. the trajectory of the
spark, how and where it "bursts", angles, distances). This way, someone else
can give you better advice on modeling should you need it.
	3. For modeling, (at least for POV) think in terms of solid 3D shapes:
spheres, cones, cylinders etc., and leave the glow and color for later.

If you are really serious, and continue to have questions, keep asking the
people on this group - it's a GREAT resource, and has helped me a lot!

Abe

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Yep, with a little work and tweaking that thing can do ANYTHING!!!

I think it's the best place to start if you're trying to make sparks.

--
Lance.


---
For the latest 3D Studio MAX plug-ins, images and much more, go to:
The Zone - http://come.to/the.zone

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OK, is this the kind of thing you're talking about?

http://www.fortunecity.com/skyscraper/parallax/359/particles.jpg

--
Lance.


---
For the latest 3D Studio MAX plug-ins, images and much more, go to:
The Zone - http://come.to/the.zone

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Lance,
That's very close to what I am talking about.  I would need to create a much
more clearer and detailed image to adequately portray the characteristic
elements the sparktester can actually visualize with the human eye.  Was
particles.jpg created with the 'spray plug-in'?  Can I get the script, or
source, for particles.jpg to play with, or tweak?

Dennis

Lance Birch wrote in message <36edd32e.0@news.povray.org>...
>OK, is this the kind of thing you're talking about?
>
>http://www.fortunecity.com/skyscraper/parallax/359/particles.jpg
>
>--
>Lance.
>
>
>---
>For the latest 3D Studio MAX plug-ins, images and much more, go to:
>The Zone - http://come.to/the.zone
>
>
>

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Well, the particles were made with 3D Studio MAX (using a VERY basic
particle system, just an emitter).  But the same principals apply for
POV-Ray with the spray plug-in.  You can find the plug-in at
http://www.geocities.com/SiliconValley/Lakes/1434/

I also added a glow effect to the particles... I guess that this could be
achived with media?  Or maybe the Lens Effects plug-in (one of Chris' also).
I'd expect that the particles you'd be modelling would be a little sharper
and smaller, like that of an arc welder?  You might want to try adding some
small "Sparkle" flares to the particles to simulate that way it looks.  I've
had very good results using Chris' "Sparkle" flare type.

Oh, by the way, the particles also have a slight motion blur on them, in
your case, considering the type of particles you're talking about, you may
want to create the particles using luminous cones based on the animation
parameters... i.e.  the base of the cone is the particle p1 at t=0.5 and the
point of the cone is p1 at t=0.45.  This way the particles will appear to
fade off as though they are being flicked from the emitter.  In
particles.jpg I used tetrahedrons which also work quite well.

Hope this helps.

--
Lance.


---
For the latest 3D Studio MAX plug-ins, images and much more, go to:
The Zone - http://come.to/the.zone

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