I have been putting a perspective grid in my scene that floats just clear of
the floor.
I use it as a visual measuring tool in the final image.
Currently I have used a grid composed of small cylinders but find that the
processing time is substantial and I am looking for an alternate idea.
Has anybody made a similar grid?

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David Vincent-Jones wrote:
> 
> I have been putting a perspective grid in my scene that floats just clear of
> the floor.
> I use it as a visual measuring tool in the final image.
> Currently I have used a grid composed of small cylinders but find that the
> processing time is substantial and I am looking for an alternate idea.
> Has anybody made a similar grid?

You might try a crossing gradient on a very thin box instead.
Something untested like this:

       box { -1,1
   texture {
   pigment { gradient x 
 color_map {
             [.45 rgbf 1][.45 rgb 1][.55 rgb 1][.55 rgbf 1]
           }
             scale .1
           }
    finish { ambient 1 diffuse 0 }
           }
   texture {
   pigment { gradient z 
 color_map {
             [.45 rgbf 1][.45 rgb 1][.55 rgb 1][.55 rgbf 1]
           }
             scale .1
           }
    finish { ambient 1.5 diffuse 0 }
           }
             scale <20,.1,20>
           }

-- 
Ken Tyler -  1200+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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David Vincent-Jones wrote:
> 
> I have been putting a perspective grid in my scene that floats just clear of
> the floor.
> I use it as a visual measuring tool in the final image.
> Currently I have used a grid composed of small cylinders but find that the
> processing time is substantial and I am looking for an alternate idea.
> Has anybody made a similar grid?

	I haven't, but if I were to do one, I'd use a plane with a gradient
layered texture, like:

texture {
  pigment {
    gradient x
    pigment_map {
      [ 0.9 color rgbf 0 transmit 1 ]
      [ 0.9 color Blue ]
    }
  }
}
texture {
  pigment {
    gradient z
    color_map {
      [ 0.9 color rgbf 0 transmit 1 ]
      [ 0.9 color Blue ]
    }
  }
}

		Jerome

-- 
*******************************

* they'll tell you what can't * mailto:ber### [at] inamecom
* be done and why...          * http://www.enst.fr/~jberger
* Then do it.                 *
*******************************

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"Jerome M. BERGER" wrote:

>         I haven't, but if I were to do one, I'd use a plane with a gradient
> layered texture, like:

I would recommend a thin box instead of a plane because the bounding is more
efficient and they render faster.

-- 
Ken Tyler -  1200+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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Ken wrote:
> 
> "Jerome M. BERGER" wrote:
> 
> >         I haven't, but if I were to do one, I'd use a plane with a gradient
> > layered texture, like:
> 
> I would recommend a thin box instead of a plane because the bounding is more
> efficient and they render faster.
> 
	You're right, but then I would use a very *thick* hollow box instead
(btw the plane should be hollow too). It should be thick enough so that
the bottom edge is below everything in the scene. A thin box would
increase the trace level (and therefore the render time) a lot...

		Jerome

-- 
*******************************

* they'll tell you what can't * mailto:ber### [at] inamecom
* be done and why...          * http://www.enst.fr/~jberger
* Then do it.                 *
*******************************

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On Tue, 09 Nov 1999 12:24:15 -0800, "Jerome M. BERGER"
<jbe### [at] enstfr> wrote:

>	You're right, but then I would use a very *thick* hollow box instead
>(btw the plane should be hollow too). It should be thick enough so that
>the bottom edge is below everything in the scene. A thin box would
>increase the trace level (and therefore the render time) a lot...
>
>		Jerome

Not if the thickness is 0, like box { <-1000,0,-1000>, <1000,0,1000> }
which, though odd, is perfectly legal.


Peter Popov
ICQ: 15002700

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Peter Popov wrote:
> 
> On Tue, 09 Nov 1999 12:24:15 -0800, "Jerome M. BERGER"
> <jbe### [at] enstfr> wrote:
> 
> >       You're right, but then I would use a very *thick* hollow box instead
> >(btw the plane should be hollow too). It should be thick enough so that
> >the bottom edge is below everything in the scene. A thin box would
> >increase the trace level (and therefore the render time) a lot...
> >
> >               Jerome
> 
> Not if the thickness is 0, like box { <-1000,0,-1000>, <1000,0,1000> }
> which, though odd, is perfectly legal.

Thanks Peter, I was just going to bring that up. It basicaly will make a box
with a thickness the same as a triangle or a disk object.

-- 
Ken Tyler -  1200+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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Peter Popov wrote:
> 
> Not if the thickness is 0, like box { <-1000,0,-1000>, <1000,0,1000> }
> which, though odd, is perfectly legal.
> 
	I didn't know you could do that... Doesn't it raise coincident surface
problems, though? Or does POV handle it in a specific way?

		Jerome

-- 
*******************************

* they'll tell you what can't * mailto:ber### [at] inamecom
* be done and why...          * http://www.enst.fr/~jberger
* Then do it.                 *
*******************************

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"Jerome M. BERGER" wrote:
> 
> Peter Popov wrote:
> >
> > Not if the thickness is 0, like box { <-1000,0,-1000>, <1000,0,1000> }
> > which, though odd, is perfectly legal.
> >
>         I didn't know you could do that... Doesn't it raise coincident surface
> problems, though? Or does POV handle it in a specific way?
> 
>                 Jerome

It handles it just like a triangle with no problems with coincident surfaces.
Renders much faster than a plane does too. Try it you'll like it :)

-- 
Ken Tyler -  1200+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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On Tue, 09 Nov 1999 13:19:13 -0800, Ken <tyl### [at] pacbellnet> wrote:

>> Not if the thickness is 0, like box { <-1000,0,-1000>, <1000,0,1000> }
>> which, though odd, is perfectly legal.
>
>Thanks Peter, I was just going to bring that up. It basicaly will make a box
>with a thickness the same as a triangle or a disk object.

Actually it was you who taught me this, so thank you too :)


Peter Popov
ICQ: 15002700

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