Hi, I was wondering how to accomplish this.
I have a sphere with a funky layered texture.  What I want to do is make
this
layered texture semi transparent, and then project light through it from
above
to a white plane below.
I've tried making it transparent by tweaking the color maps' filter
settings,
and that doesn't work.  I ended up using a texture_map average with
pigment {rgbf <1,1,1,1>} and that sort of gets the job done, but now my
colors are washed out and no matter how bright my light is, the projected
colors are dull.

Is there a way to get a realistic projector effect in regular or megaPOV? 
i.e.
like projecting light through a slide and onto a white movie screen?
Can I make the plane pick up colors better?

Or maybe a better question is how do I take my funky bozo/marble/crackle
sphere and make it semi-transparent the way I want, with full colors?

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CreeD <mes### [at] nqinet> wrote:
> Hi, I was wondering how to accomplish this.
> I have a sphere with a funky layered texture.  What I want to do is make
> this
> layered texture semi transparent, and then project light through it from
> above
> to a white plane below.
> I've tried making it transparent by tweaking the color maps' filter
> settings,
> and that doesn't work.  I ended up using a texture_map average with
> pigment {rgbf <1,1,1,1>} and that sort of gets the job done, but now my
> colors are washed out and no matter how bright my light is, the projected
> colors are dull.
>
> Is there a way to get a realistic projector effect in regular or megaPOV?
> i.e.
> like projecting light through a slide and onto a white movie screen?
> Can I make the plane pick up colors better?
>
> Or maybe a better question is how do I take my funky bozo/marble/crackle
> sphere and make it semi-transparent the way I want, with full colors?

For maximum colouration of the light you'll want to use a filter value of 1,
with saturated colours, e.g. rgbf <1, 0, 0, 1> will filter white light to be
completely red, whereas rgbf <1, .5, .5, 1> will give a washed out red.  You
could also try decreasing the ambient and increasing the diffuse finish
values of your plane to increase the contrast and brightness of the
reflected light.

Apart from that, there shouldn't be any reason why you can't use
multi-layered, semi-transparent textures as a projector - I've just tried a
quick example myself in official POV and everything seems to work as
expected.  Perhaps some code would help to clarify the problem...

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the problem you may have is that there is no transparent path right
through the object.  one idea is surface texturing.  i think there was
something in the megapov docs about it.  thant would give you a texture
on the surface with a hollow inside.  speaking of hollow, i know hollow
is needed for media to be visible, but i don't know how or if it affects
objects with textures.  also, as an experiment, try starting with a
totally clear sphere and adding each layer one at a time so you can see
the effect each has to the overall transparency.  remember that the top
layers need to have the most transparent areas so the bottom ones can
show through.

CreeD wrote:
> 
> Hi, I was wondering how to accomplish this.
> I have a sphere with a funky layered texture.  What I want to do is make
> this
> layered texture semi transparent, and then project light through it from
> above
> to a white plane below.
> I've tried making it transparent by tweaking the color maps' filter
> settings,
> and that doesn't work.  I ended up using a texture_map average with
> pigment {rgbf <1,1,1,1>} and that sort of gets the job done, but now my
> colors are washed out and no matter how bright my light is, the projected
> colors are dull.
> 
> Is there a way to get a realistic projector effect in regular or megaPOV?
> i.e.
> like projecting light through a slide and onto a white movie screen?
> Can I make the plane pick up colors better?
> 
> Or maybe a better question is how do I take my funky bozo/marble/crackle
> sphere and make it semi-transparent the way I want, with full colors?

Post a reply to this message

"Chris Colefax" <chr### [at] tagpovrayorg> wrote in message
news:396d055b@news.povray.org...
| CreeD <mes### [at] nqinet> wrote:
| > Hi, I was wondering how to accomplish this.
| > I have a sphere with a funky layered texture.  What I want to do is make
| > this
| > layered texture semi transparent, and then project light through it from
| > above
| > to a white plane below.
|
| Apart from that, there shouldn't be any reason why you can't use
| multi-layered, semi-transparent textures as a projector -

Ah, but remember that official POV-Ray versions change layers to 'transmit' regardless
of using
'filter' in them or not.  That could be the problem.
Other than that, Chris is right, drop the ambient to zero, use diffuse 1 (or higher)
and use a rgb
1 or higher for the light source or plane color also (but probably not both).

Bob

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The suggestions for fixing the plane's ambient and diffuse helped a lot.

I figured out what the problem was -
The problem was that I'm too lazy to manually tweak 4 or 5 10-part color
maps
to get the colors to stop being washed out =)
Even the shortcuts are time consuming.
I tried the same deal with a box instead of a sphere and the results were
much better.

Thanks to all who replied.

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