Hi,
	I was wondering if it was possible to tell an object to cast no reflection? 
Probably much like a "vampire effect" ;) or like the media_interaction or
cast_shadow in lights... etc...

Any ideas?

Thanks,
	Simon
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| Simon Lemieux           | Website : http://www.666Mhz.net  |
| Email : Sin### [at] 666Mhznet | POV-Ray, OpenGL, C++ and more... |
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In article <3A0DE308.EC379B17@yahoo.com>, lem### [at] yahoocom wrote:

> 	I was wondering if it was possible to tell an object to cast no 
> reflection? 
> Probably much like a "vampire effect" ;) or like the media_interaction or
> cast_shadow in lights... etc...

"cast_shadow"? You mean "shadowless"? Or was it "no_shadow", I can never 
remember which one is used for light_sources...
I think what you want is the "no_reflection" keyword in 
MegaPOV...standard POV doesn't have special support for this feature, 
you have to trick it by using fancy bounding.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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Chris Huff wrote:
> 
> standard POV doesn't have special support for this feature,
> you have to trick it by using fancy bounding.
> 

Specifically, bound the object with very small boxes/spheres near (or around)
the camera, and any light_sources that you want this object to interact with.

-- 
Margus Ramst

Personal e-mail: mar### [at] peakeduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg

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Chris Huff wrote:

> "cast_shadow"? You mean "shadowless"? Or was it "no_shadow", I can never
> remember which one is used for light_sources...

The way I remember is that no_shadow is singular but shadowless can be plural.
So no_shadow is for objects and shadowless is for lights.

> I think what you want is the "no_reflection" keyword in
> MegaPOV...standard POV doesn't have special support for this feature,
> you have to trick it by using fancy bounding.

Interesting, I never thought of that. You mean like bound it with a polygon
that from the camera's viewpoint contains the object?

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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Margus Ramst wrote:

> Specifically, bound the object with very small boxes/spheres near (or around)
> the camera, and any light_sources that you want this object to interact with.

Ah...

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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David Fontaine wrote:

> > I think what you want is the "no_reflection" keyword in
> > MegaPOV...standard POV doesn't have special support for this feature,
> > you have to trick it by using fancy bounding.
>
> Interesting, I never thought of that. You mean like bound it with a polygon
> that from the camera's viewpoint contains the object?

That's right, I forgot lights...

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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> Specifically, bound the object with very small boxes/spheres near (or around)
> the camera, and any light_sources that you want this object to interact with.

Interesting, so, will doing these bounding boxes hack make my object appear in
front of the camera but not in the mirror beside it?

Thanks,
	Simon

-- 
+-------------------------+----------------------------------+
| Simon Lemieux           | Website : http://www.666Mhz.net  |
| Email : Sin### [at] 666Mhznet | POV-Ray, OpenGL, C++ and more... |
+-------------------------+----------------------------------+

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Simon Lemieux wrote:
> 
> Hi,
> I was wondering if it was possible to tell an object to cast
> no reflection? Probably much like a "vampire effect" ;) or like the
> media_interaction or cast_shadow in lights... etc...

I think the way to do it is to give it a bounding object that surrounds
the camera viewpoint.  This way the reflected rays miss the bounding
object and cause it to not appear.

object {
  Vampire
  bounded_by { sphere { CameraLocation,.01 } }
}

Rays from the camera will always intersect the sphere, hence the
object will directly appear; but the reflected rays will almost
certainly miss that sphere, causing the object to not appear in the
reflection.

Regards,
John
-- 
ICQ: 46085459

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> I think the way to do it is to give it a bounding object that surrounds
> the camera viewpoint.  This way the reflected rays miss the bounding
> object and cause it to not appear.
> 
> object {
>   Vampire
>   bounded_by { sphere { CameraLocation,.01 } }
> }
> 
> Rays from the camera will always intersect the sphere, hence the
> object will directly appear; but the reflected rays will almost
> certainly miss that sphere, causing the object to not appear in the
> reflection.

Very interesting!...  But... it doesn't seem to work...

I tried the simplified scene with a white sphere and a mirror, the bounded_by is
set to the camera position, everything seems alright, but I see two spheres...

Do I need any other keywords in order to make this work?

Thanks,
	Simon
-- 
+-------------------------+----------------------------------+
| Simon Lemieux           | Website : http://www.666Mhz.net  |
| Email : Sin### [at] 666Mhznet | POV-Ray, OpenGL, C++ and more... |
+-------------------------+----------------------------------+

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In article <3A0E1A03.3FEA6199@faricy.net>, David Fontaine 
<dav### [at] faricynet> wrote:

> The way I remember is that no_shadow is singular but shadowless can be 
> plural.
> So no_shadow is for objects and shadowless is for lights.

But if you have more than one light, you object has as many shadows as 
you have light sources...


> Interesting, I never thought of that. You mean like bound it with a 
> polygon that from the camera's viewpoint contains the object?

Bound it with a union of spheres or boxes, one around the camera and one 
around each light that you want it to interact with.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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