Hi guys:

I've got a problem. I would like to simulate a broken glass in several stages. I
mean, first the glass is hit so it goes moreless like this:
http://www.alucare.co.uk/controlpanel/shoppics/Image/broken%20glass.JPG
and then the glass is broken into pieces. I know moreless how to do the second
stage.

But the first one is quite more difficult. I have tried by texturing a box with
a crackled texture but no way. Then I have tried with an image_map, but again,
no success. It looks too much like an image, you know what I mean. A third idea
would be to divide the glass into pieces and to put them together (with a cgs
for example). I havent tried this last one.

The question is: do you know about someone working in something similar?

thanks on advance.

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"kike" <dry### [at] hotmailcom> wrote in message 
news:web.47fdd7d17def4b5dbe7bfb550@news.povray.org...
>
> Hi guys:
>
> I've got a problem. I would like to simulate a broken glass in several 
> stages. I
> mean, first the glass is hit so it goes moreless like this:
> http://www.alucare.co.uk/controlpanel/shoppics/Image/broken%20glass.JPG
> and then the glass is broken into pieces. I know moreless how to do the 
> second
> stage.
>
> But the first one is quite more difficult. I have tried by texturing a box 
> with
> a crackled texture but no way. Then I have tried with an image_map, but 
> again,
> no success. It looks too much like an image, you know what I mean. A third 
> idea
> would be to divide the glass into pieces and to put them together (with a 
> cgs
> for example). I havent tried this last one.
>
> The question is: do you know about someone working in something similar?
>
> thanks on advance.
>

I've not done anything like this, but variations of the two approaches you 
mention are what spring to my mind.

Starting with a crackle pattern with blackhole warps to concentrate the 
pattern around the holes. You could overlay turbulent radial patterns 
eminating from the holes. To get the fractures through the glass thickness 
you could use the same pattern as a height field then slice off the top and 
bottom with a plane bearing the pattern. That way you could give the height 
field a higher ambient setting to emulate the white veins inside the body of 
the glass.

Plan B - If you intend to define individual pieces that fit together for the 
flying glass, then you could use those pieces for the intact, cracked piece. 
You could give each piece a bright white edge by using an copy of that piece 
as an object pigment, scaled down very slightly in X and Y and scaled up in 
Z (centre on origin, scale and translate back again). I recall seeing a 
POV-Ray image on this news group that applied thick black lines around 
objects to achieve a cartoon-like effect, I don't know if they used this 
technique, but, if the author published their technique then you might be 
able to adapt something from that.

Regards,
Chris B.

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kike <dry### [at] hotmailcom> wrote:
> The question is: do you know about someone working in something similar?

  If that's the only thing you are asking, then the answer is no.

  OTOH, I can go ahead and ponder about your problem more.

  A broken glass is a 3D effect. I don't think it can be reliably
simulated with a surface texture. You'll have to create the microfissures
inside the glass which cause light to bend differently. Also the surface
of these microfissures is probably not completely transparent, as the
original glass surface is.

  I suppose the only way to simulate that is to try to copy exactly
what happens in real life: You'll have to create the microfissures
as geometry (texture tricks won't probably do), and you'll have to
give a less transparent texture to the surfaces of these fissures.

-- 
                                                          - Warp

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Warp <war### [at] tagpovrayorg> wrote:
>   A broken glass is a 3D effect. I don't think it can be reliably
> simulated with a surface texture. >                                                 
         - Warp

Yeah, you are right, this is the kind of things you can do with textures...
http://www.enriquesahagun.es/crackle.png
probably you can get better results this way but somehow you loose the
3dimensionality of the problem...

anyway, thanks

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kike nous apporta ses lumieres en ce 2008/04/10 05:03:
> Hi guys:
> 
> I've got a problem. I would like to simulate a broken glass in several stages. I
> mean, first the glass is hit so it goes moreless like this:
> http://www.alucare.co.uk/controlpanel/shoppics/Image/broken%20glass.JPG
> and then the glass is broken into pieces. I know moreless how to do the second
> stage.
> 
> But the first one is quite more difficult. I have tried by texturing a box with
> a crackled texture but no way. Then I have tried with an image_map, but again,
> no success. It looks too much like an image, you know what I mean. A third idea
> would be to divide the glass into pieces and to put them together (with a cgs
> for example). I havent tried this last one.
> 
> The question is: do you know about someone working in something similar?
> 
> thanks on advance.
> 
> 
Aparently, you want some kind of animation of the glass breaking apart. So, you 
already need to define your peices.
In that case, my aproach would be to start by creating all the pieces. Once the 
pieces are done, place them togheder in a planar configuration.

The bright lines are caused by a combination of total internal reflection and 
miltiple surface reflections between the edges of 2 adjacent pieces. Those 
surfaces are no less transparent than the original surfaces, in fact, they can 
be even MORE transparent as they are "new" surfaces without any grime nor 
scratches. If you want to give them a different texture, make it slightly more 
reflective.

-- 
Alain
-------------------------------------------------
Buy Land Now. It's Not Being Made Any More.

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I actually did a broken glass a few years back. The method I used was to create
a jagged height field and use this as a cutting object in a CSG difference. You
have to do it twice for each piece, one to remove the broken part and then again
to create the fragment. When you are done you can just assemble the pieces in
place and animate them coming apart.


Alain <ele### [at] netscapenet> wrote:
> kike nous apporta ses lumieres en ce 2008/04/10 05:03:
> > Hi guys:
> >
> > I've got a problem. I would like to simulate a broken glass in several stages. I
> > mean, first the glass is hit so it goes moreless like this:
> > http://www.alucare.co.uk/controlpanel/shoppics/Image/broken%20glass.JPG
> > and then the glass is broken into pieces. I know moreless how to do the second
> > stage.
> >
> > But the first one is quite more difficult. I have tried by texturing a box with
> > a crackled texture but no way. Then I have tried with an image_map, but again,
> > no success. It looks too much like an image, you know what I mean. A third idea
> > would be to divide the glass into pieces and to put them together (with a cgs
> > for example). I havent tried this last one.
> >
> > The question is: do you know about someone working in something similar?
> >
> > thanks on advance.
> >
> >
> Aparently, you want some kind of animation of the glass breaking apart. So, you
> already need to define your peices.
> In that case, my aproach would be to start by creating all the pieces. Once the
> pieces are done, place them togheder in a planar configuration.
>
> The bright lines are caused by a combination of total internal reflection and
> miltiple surface reflections between the edges of 2 adjacent pieces. Those
> surfaces are no less transparent than the original surfaces, in fact, they can
> be even MORE transparent as they are "new" surfaces without any grime nor
> scratches. If you want to give them a different texture, make it slightly more
> reflective.
>
> --
> Alain
> -------------------------------------------------
> Buy Land Now. It's Not Being Made Any More.

Post a reply to this message