Hy everybody!

How can I create an invisible plane to shade objects? I need this, because
there's an another object, what have a lot of point lights, and their power are
too strong.

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"gregtom6" <gre### [at] freemailhu> wrote:
> Hy everybody!
>
> How can I create an invisible plane to shade objects? I need this, because
> there's an another object, what have a lot of point lights, and their power are
> too strong.

The following flags can be set in any objects individually or together:

no_image: object is not visible directly, but produces shadows and is visible in
reflections

no_reflection:  object is visible, but not in reflections

no_shadow: object does not produce a shadow


In your case it looks like you would want to add the no_image and no_reflection
flags to your plane.

See 3.4.9.7 & 3.4.9.9 of the docs for more info.

-tgq

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> Hy everybody!
>
> How can I create an invisible plane to shade objects? I need this, because
> there's an another object, what have a lot of point lights, and their power are
> too strong.
>
>
>

How about reducing the power of your point_lights, or beter, combine 
them into one area_light? Good if they are aranged into a squarish, 
circular or spherical pattern.

The area_light would have the advantage of been faster, especialy if you 
use the adaptive feature.
Add circular to have it act as if it was a disk.
Also add orient to have it acts like a sperical light.

Anyway, you can add no_image to any object. The affected object will 
still cast shadows and be visible in reflection. If you also want it to 
eacape reflection, then also add no_reflection.



Alain

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On 04/06/2011 03:06 PM, gregtom6 wrote:
> Hy everybody!
>
> How can I create an invisible plane to shade objects? I need this, because
> there's an another object, what have a lot of point lights, and their power are
> too strong.
>
>
>
You can vary the see through properties of the plane (or any other 
object) with pigment identifiers ... rgbt or rgbf is what you should be 
looking for:

http://wiki.povray.org/content/Documentation:Reference_Section_2.1#Specifying_Colors

But maybe you don't need to shade with an object. You could vary the 
strength of the light source ...

http://wiki.povray.org/content/Documentation:Tutorial_Section_2.1#The_Light_Source

maybe fade distance might be helpful, but have a look at the entire 
tutorial just to get a feel for what's going on.

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Alain <aze### [at] qwertyorg> wrote:

> > Hy everybody!
> >
> > How can I create an invisible plane to shade objects? I need this, because
> > there's an another object, what have a lot of point lights, and their power are
> > too strong.
> >
> >
> >
>
> How about reducing the power of your point_lights, or beter, combine
> them into one area_light? Good if they are aranged into a squarish,
> circular or spherical pattern.
>
> The area_light would have the advantage of been faster, especialy if you
> use the adaptive feature.
> Add circular to have it act as if it was a disk.
> Also add orient to have it acts like a sperical light.
>
> Anyway, you can add no_image to any object. The affected object will
> still cast shadows and be visible in reflection. If you also want it to
> eacape reflection, then also add no_reflection.
>
>
>
> Alain
The lightning object is a spaceship, and it has got a lot of point lights. If I
reduce the fade distance and/or fade power, that won't light the ship.
The lights are enough strong on the ship, but too strong, if an object is too
close to the ship.

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gregtom6 wrote:

> The lightning object is a spaceship, and it has got a lot of point lights. If I
> reduce the fade distance and/or fade power, that won't light the ship.
> The lights are enough strong on the ship, but too strong, if an object is too
> close to the ship.

In case you want to render a realistic image, you can't have it both
ways. If you think it looks odd, then something may be wrong about other
setup. If there are lights directly on the ship they would not provide
much light to the hull, as the angle of incidence will be very small.
So if you think the ship should be bright, the hull itself needs to
be glowing (ambient/emissive) or you need an external light source
such as a star.

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Christian Froeschlin <chr### [at] chrfrde> wrote:
> gregtom6 wrote:
>
> > The lightning object is a spaceship, and it has got a lot of point lights. If I
> > reduce the fade distance and/or fade power, that won't light the ship.
> > The lights are enough strong on the ship, but too strong, if an object is too
> > close to the ship.
>
> In case you want to render a realistic image, you can't have it both
> ways. If you think it looks odd, then something may be wrong about other
> setup. If there are lights directly on the ship they would not provide
> much light to the hull, as the angle of incidence will be very small.
> So if you think the ship should be bright, the hull itself needs to
> be glowing (ambient/emissive) or you need an external light source
> such as a star.

No. I want only small light sources on the hull, to light small areas.
My ship has got a lot of small point lights, and it seems to be there're a lot
of lamps on the ship.

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"gregtom6" <gre### [at] freemailhu> wrote:
> Christian Froeschlin <chr### [at] chrfrde> wrote:
> > gregtom6 wrote:
> >
> > > The lightning object is a spaceship, and it has got a lot of point lights. If I
> > > reduce the fade distance and/or fade power, that won't light the ship.
> > > The lights are enough strong on the ship, but too strong, if an object is too
> > > close to the ship.
> >
> > In case you want to render a realistic image, you can't have it both
> > ways. If you think it looks odd, then something may be wrong about other
> > setup. If there are lights directly on the ship they would not provide
> > much light to the hull, as the angle of incidence will be very small.
> > So if you think the ship should be bright, the hull itself needs to
> > be glowing (ambient/emissive) or you need an external light source
> > such as a star.
>
> No. I want only small light sources on the hull, to light small areas.
> My ship has got a lot of small point lights, and it seems to be there're a lot
> of lamps on the ship.

Ok, I finally solved this problem. When I gave 0 value to fade distance, it went
wrong, but when I changed that to 1, it solved the problem:)

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"gregtom6" <gre### [at] freemailhu> wrote:
> "gregtom6" <gre### [at] freemailhu> wrote:
> > Christian Froeschlin <chr### [at] chrfrde> wrote:
> > > gregtom6 wrote:
> > >
> > > > The lightning object is a spaceship, and it has got a lot of point lights. If
I
> > > > reduce the fade distance and/or fade power, that won't light the ship.
> > > > The lights are enough strong on the ship, but too strong, if an object is too
> > > > close to the ship.
> > >
> > > In case you want to render a realistic image, you can't have it both
> > > ways. If you think it looks odd, then something may be wrong about other
> > > setup. If there are lights directly on the ship they would not provide
> > > much light to the hull, as the angle of incidence will be very small.
> > > So if you think the ship should be bright, the hull itself needs to
> > > be glowing (ambient/emissive) or you need an external light source
> > > such as a star.
> >
> > No. I want only small light sources on the hull, to light small areas.
> > My ship has got a lot of small point lights, and it seems to be there're a lot
> > of lamps on the ship.
>
> Ok, I finally solved this problem. When I gave 0 value to fade distance, it went
> wrong, but when I changed that to 1, it solved the problem:)

Yes, as per recent discussions, fade distance should be small, but not that
small!

-tgq

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> Christian Froeschlin<chr### [at] chrfrde>  wrote:
>> gregtom6 wrote:
>>
>>> The lightning object is a spaceship, and it has got a lot of point lights. If I
>>> reduce the fade distance and/or fade power, that won't light the ship.
>>> The lights are enough strong on the ship, but too strong, if an object is too
>>> close to the ship.
>>
>> In case you want to render a realistic image, you can't have it both
>> ways. If you think it looks odd, then something may be wrong about other
>> setup. If there are lights directly on the ship they would not provide
>> much light to the hull, as the angle of incidence will be very small.
>> So if you think the ship should be bright, the hull itself needs to
>> be glowing (ambient/emissive) or you need an external light source
>> such as a star.
>
> No. I want only small light sources on the hull, to light small areas.
> My ship has got a lot of small point lights, and it seems to be there're a lot
> of lamps on the ship.
>
>

In that case, you can use spot_light that point at the hull's areas that 
you want illuminated.
Just remenber that the radius is in degrees, not in units around the 
point_at location. (I've seen scenes with that mistake)

You can still use fade_distance and fade_power for those.
As a bonus, you may get some speed improvements as you will save on the 
shadow ray tests.



Alain

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