For example, disco mirror-balls and sequins on clothing catch light and reflect
it.
Also, silver glitter seems to refract light in a spectrum, not just white or
silver.

My intent is making a movie that has 'random' flashes and flickers.

Thanks in advance for any suggestions.

Leef_me

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"Leef_me" <nomail@nomail> wrote:
> For example, disco mirror-balls and sequins on clothing catch light and reflect
> it.
>
> My intent is making a movie that has 'random' flashes and flickers.
>
> Thanks in advance for any suggestions.
>
> Leef_me

For a disco mirror ball, I think the best thing to use would be a mesh with a
reflective and highly specular texture in conjunction with photon mapping. I
have noticed a similar effect with some diamonds I have made the same way.

For sequins on clothing, while I haven't actually done anything involving
people,
a texture_map seems to me to be the best course, for example

object {
  Clothing
  texture {
    bozo texture_map {
    [ 0.1 Sequins ]   //play around with these values
    [ 0.2 Cloth ]
   }
   scale //appropriate scale value
}

The Sequins texture would have to have a high reflection value, > 0.6, like the
disco ball. If you want a spectrum of reflected colours, use dispersion in the
interior statement of the object.

You could of course fake the colours, by making a more complex texture_map with
random colours. I have a random colour macro that I would be willing to post if
you're interested.

Be aware that photon mapping takes time, my diamonds scene took 25 minutes to
render at 800x600, for a 30 fps animation, this would mean >14 hours to render,
assuming that you are moving/rotating the objects that use photons, if not, use
a photon save_file.

Hope this helps,
D103

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"D103" <nomail@nomail> wrote:
> "Leef_me" <nomail@nomail> wrote:
> > For example, disco mirror-balls and sequins on clothing catch light and reflect
> > it.
> >
> > My intent is making a movie that has 'random' flashes and flickers.
> >
> > Thanks in advance for any suggestions.
> >
> > Leef_me
>
> For a disco mirror ball, I think the best thing to use would be a mesh with a
> reflective and highly specular texture in conjunction with photon mapping. I
> have noticed a similar effect with some diamonds I have made the same way.
>
> For sequins on clothing, while I haven't actually done anything involving
> people,
> a texture_map seems to me to be the best course, for example
>
> object {
>   Clothing
>   texture {
>     bozo texture_map {
>     [ 0.1 Sequins ]   //play around with these values
>     [ 0.2 Cloth ]
>    }
>    scale //appropriate scale value
> }
>
> The Sequins texture would have to have a high reflection value, > 0.6, like the
> disco ball. If you want a spectrum of reflected colours, use dispersion in the
> interior statement of the object.
>
> You could of course fake the colours, by making a more complex texture_map with
> random colours. I have a random colour macro that I would be willing to post if
> you're interested.
>
> Be aware that photon mapping takes time, my diamonds scene took 25 minutes to
> render at 800x600, for a 30 fps animation, this would mean >14 hours to render,
> assuming that you are moving/rotating the objects that use photons, if not, use
> a photon save_file.
>
> Hope this helps,
> D103

Hi again,

I've done some experimenting, and the mesh gave the expected results for a
mirror ball, but I could not get a decent cloth/sequins texture. However, see
what you can come up with.

An image_map might be the next best thing, but I doubt you could get the
required caustics from it.

Regards,
D103

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> For a disco mirror ball, I think the best thing to use would be a mesh with a
> reflective and highly specular texture in conjunction with photon mapping. 

A sphere with facet normals would also be an option.


Regarding the sequins, some 2d pattern such as leopard
could be used to fake the reflective spots for objects that
support uv_mapping, e.g:

#declare T_BASE   = texture {pigment {color White}}

#declare T_SEQUIN = texture {T_Gold_1A}


sphere
{
   y,1

   texture
   {
     uv_mapping

     // roundish spots

     leopard

     scale 0.005

     texture_map
     {
       [0.00 T_BASE]
       [0.01 T_BASE]
       [0.01 T_SEQUIN]
       [1.00 T_SEQUIN]
     }
     */


     // hexagonalish (requires version 3.7)
     /*
     tiling 2 rotate 90 * x

     turbulence 0.1

     scale 0.005

     texture_map
     {
       [0.00 T_SEQUIN]
       [0.92 T_SEQUIN]
       [0.92 T_BASE]
       [1.00 T_BASE]
     }
     */
   }
}

Although these spots can reflect photons they are not flat, though.

Post a reply to this message

> For example, disco mirror-balls and sequins on clothing catch light and reflect
> it.
> Also, silver glitter seems to refract light in a spectrum, not just white or
> silver.
>
> My intent is making a movie that has 'random' flashes and flickers.
>
> Thanks in advance for any suggestions.
>
> Leef_me
>
>

If you are only concerned with the visual flash, you don't need photons, 
only a strong, and relatively tight, specular or phong highlight.

You do need photons if you want to see the reflected beams on 
surrounding surfaces.

The facet normal pattern can be usefull. There are 2 versions, one for 
mostly flat surfaces and one for curved ones.

If you want to have coloured reflections, you can use the aoi pattern to 
have variously coloured reflections. The facet pattern can be usefull 
here also.

You can also use small transparent prisms with some ior and dispersion. 
Dispersion will increase rendering time, especialy if using photons.



Alain

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