Is it possible to apply bilinear filtering effect in Povray to make the
scene more smooth.

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"SSSUTM" <nomail@nomail> wrote in message 
news:web.43608a3667789c1136a46a7d0@news.povray.org...
> Is it possible to apply bilinear filtering effect in Povray to make the
> scene more smooth.

Do you mean bilinear interpolation for in use on image_map pigments?
http://www.povray.org/documentation/view/3.6.1/337/
and http://www.povray.org/documentation/view/3.6.1/408/

Or could you mean smoothing edges in the entire scene?
There's antialiasing, which jitters and averages multisamples through pixels 
to reduce the stairstepping on edges: 
http://www.povray.org/documentation/view/3.6.1/223/

Cheers,
    Brian

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What I mean is that like in games, bilinear filtering will mix the pixels of
an entire scene so that it appears smooth and you don't see the pixels as
such but mixed.

By the way, I have downloaded some models from 3D cafe. When I import them
in povray, they are very big. I need to reduce the size of the entire
object. Can you suggest any functions that I can apply to make them
smaller.



"Brian Elliott" <NotForSpam@AskIfUWant> wrote:
> "SSSUTM" <nomail@nomail> wrote in message
> news:web.43608a3667789c1136a46a7d0@news.povray.org...
> > Is it possible to apply bilinear filtering effect in Povray to make the
> > scene more smooth.
>
> Do you mean bilinear interpolation for in use on image_map pigments?
> http://www.povray.org/documentation/view/3.6.1/337/
> and http://www.povray.org/documentation/view/3.6.1/408/
>
> Or could you mean smoothing edges in the entire scene?
> There's antialiasing, which jitters and averages multisamples through pixels
> to reduce the stairstepping on edges:
> http://www.povray.org/documentation/view/3.6.1/223/
>
> Cheers,
>     Brian

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> What I mean is that like in games, bilinear filtering will mix the pixels
of
> an entire scene so that it appears smooth and you don't see the pixels as
> such but mixed.

Well, "mix the pixels of an entire scene" sounds like a blurring effect, but
I don't think that's what you mean. I think you're referring to
anti-aliasing (see http://en.wikipedia.org/wiki/Anti-aliasing for an
explanation, see Brian's post for usage details).

> By the way, I have downloaded some models from 3D cafe. When I import them
> in povray, they are very big. I need to reduce the size of the entire
> object. Can you suggest any functions that I can apply to make them
> smaller.

You can use the "scale" keyword to do this. For instance:

sphere {
    <0,0,0>, 1
    scale 0.1
}

 - Slime
 [ http://www.slimeland.com/ ]

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SSSUTM <nomail@nomail> wrote:
> What I mean is that like in games, bilinear filtering will mix the pixels of
> an entire scene so that it appears smooth and you don't see the pixels as
> such but mixed.

  I think that you have a confusion here.

  Bilinear filtering is used (usually in scanline rendering, which is what
3D hardware uses) in texturing (and since it's scanline rendering, the
textured elements are triangles). And it's only useful when the texture
pixels (ie. texels) are larger than the image pixels.
  When the texture to draw on screen has bigger texels than the screen
pixels, what bilinear filtering does is to interpolate between the
texels colors. ("Bilinear" means that the interpolation is done in
both texture axes.) This will make the texture look smoother and less
pixelated when it is zoomed bigger.

  Bilinear filtering can only be done to textures. It will not smooth out
polygon edges. This means that objects will have pixelated edges regardless
of whether you use bilinear filtering or not.

  In order to smooth polygon edges what you need is *antialiasing*, which
is a completely different and unrelated technique.

> By the way, I have downloaded some models from 3D cafe. When I import them
> in povray, they are very big.

  Have you imported them in mesh2 format?

-- 
                                                          - Warp

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