Apart from the obligatory nag about the superpatch update :) I have a
request/query

Do you remember the thread about noise and basic shapes so months ago?

Well is possible to add noise and to HFs? not in the sense of graphic noise
but in a way similar to that the isopatch uses.

If so, if it's easy to add, can we have it?

Mick

Post a reply to this message

On Thu, 8 Jul 1999 18:45:17 +0100, Mick Hazelgrove wrote:
>Apart from the obligatory nag about the superpatch update :) I have a
>request/query
>
>Do you remember the thread about noise and basic shapes so months ago?
>
>Well is possible to add noise and to HFs? not in the sense of graphic noise
>but in a way similar to that the isopatch uses.
>
>If so, if it's easy to add, can we have it?

I'm not sure what you mean.  Are you wanting to add a higher-frequency
noise to a lower-frequency heightfield (i.e. more than one noise sample
per pixel)?

There is a way you can fake it with the iso patch, though it's probably
kinda slow.  The 3.1e superpatch has a pigment function that, afaik, 
should work with an interpolated imagemap to give you a nice isosurface
approximation of a heightfield.  Once you get that working, you can 
then add any function you want to it, including noise.

Post a reply to this message

On 8 Jul 1999 17:31:34 -0400, Ron Parker wrote:
>On Thu, 8 Jul 1999 18:45:17 +0100, Mick Hazelgrove wrote:
>>Apart from the obligatory nag about the superpatch update :) I have a
>>request/query
>>
>>Do you remember the thread about noise and basic shapes so months ago?
>>
>>Well is possible to add noise and to HFs? not in the sense of graphic noise
>>but in a way similar to that the isopatch uses.
>>
>>If so, if it's easy to add, can we have it?
>
>I'm not sure what you mean.  Are you wanting to add a higher-frequency
>noise to a lower-frequency heightfield (i.e. more than one noise sample
>per pixel)?
>
>There is a way you can fake it with the iso patch, though it's probably
>kinda slow.  The 3.1e superpatch has a pigment function that, afaik, 
>should work with an interpolated imagemap to give you a nice isosurface
>approximation of a heightfield.  Once you get that working, you can 
>then add any function you want to it, including noise.

Here's a sample showing what I mean.  For some reason the bilinear interpolation
doesn't seem quite as useful as I thought it would, but here ya go anyway.  You
should substitute your own heightfield where I have sphere.bmp.  The .001 is 
used to chop off the planar surface that would otherwise be generated by the
black background in my test image.

//--------- cut here ----->8=======
camera {location <0,3,-3> look_at 0}
light_source {<-20,20,-20> rgb <.8,.8,1>}
light_source {<20,20,-20> rgb <1,.8,.8>}

#declare xx=function{
  pigment {
    image_map {
      sys "sphere.bmp" 
      interpolate 2
    } 
  rotate 90*x
  }
}

isosurface {
  function{y-xx(x,y,z)+.001+.05*noise3d(20*x,20*y,20*z)}
  bounded_by {box {0,1}}
  eval                  
  translate -.5
  scale 3
  texture {
    pigment {color rgb 1}
    finish {ambient .3}
  }
}
//--------- cut here ----->8=======

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Sounds interesting  - I'm about to fall asleep over this keyboard so I'll
give it a go tomorrozzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz
zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz!

Mick

Ron Parker <par### [at] fwicom> wrote in message
news:37851e51@news.povray.org...
> On 8 Jul 1999 17:31:34 -0400, Ron Parker wrote:
> >On Thu, 8 Jul 1999 18:45:17 +0100, Mick Hazelgrove wrote:
> >>Apart from the obligatory nag about the superpatch update :) I have a
> >>request/query
> >>
> >>Do you remember the thread about noise and basic shapes so months ago?
> >>
> >>Well is possible to add noise and to HFs? not in the sense of graphic
noise
> >>but in a way similar to that the isopatch uses.
> >>
> >>If so, if it's easy to add, can we have it?
> >
> >I'm not sure what you mean.  Are you wanting to add a higher-frequency
> >noise to a lower-frequency heightfield (i.e. more than one noise sample
> >per pixel)?
> >
> >There is a way you can fake it with the iso patch, though it's probably
> >kinda slow.  The 3.1e superpatch has a pigment function that, afaik,
> >should work with an interpolated imagemap to give you a nice isosurface
> >approximation of a heightfield.  Once you get that working, you can
> >then add any function you want to it, including noise.
>
> Here's a sample showing what I mean.  For some reason the bilinear
interpolation
> doesn't seem quite as useful as I thought it would, but here ya go anyway.
You
> should substitute your own heightfield where I have sphere.bmp.  The .001
is
> used to chop off the planar surface that would otherwise be generated by
the
> black background in my test image.
>
> file://--------- cut here ----->8=======
> camera {location <0,3,-3> look_at 0}
> light_source {<-20,20,-20> rgb <.8,.8,1>}
> light_source {<20,20,-20> rgb <1,.8,.8>}
>
> #declare xx=function{
>   pigment {
>     image_map {
>       sys "sphere.bmp"
>       interpolate 2
>     }
>   rotate 90*x
>   }
> }
>
> isosurface {
>   function{y-xx(x,y,z)+.001+.05*noise3d(20*x,20*y,20*z)}
>   bounded_by {box {0,1}}
>   eval
>   translate -.5
>   scale 3
>   texture {
>     pigment {color rgb 1}
>     finish {ambient .3}
>   }
> }
> file://--------- cut here ----->8=======

Post a reply to this message

On Thu, 8 Jul 1999 18:45:17 +0100, "Mick Hazelgrove"
<mha### [at] mindaswinternetcouk> wrote:
>
>Well is possible to add noise and to HFs? not in the sense of graphic noise
>but in a way similar to that the isopatch uses.
>

Wouldn't it give the same results to add noise to the original image
used for the heightfield? That might be a simpler method.


Later,
Glen Berry

IMP Vice Coordinator, and Communications Director
IMP Website: www.imp.org
My Website:  www.ezwv.com/~mclilith/index.html

Email:  7no### [at] ezwvcom
(remove the "7" to reply via personal email)

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> Wouldn't it give the same results to add noise to the original image
> used for the heightfield? That might be a simpler method.

No I'm not after that effect, I'm looking for something that will distort
the HF. Take one HF made of clay and push and pull it about a bit. It still
retains the basic shape but now there are xtra bumps and lumps ridges and
dents. Noise simply adds spikes.

I have a feeling that adding 3Dnoise as in the superpatch and isopatch
objects to the HF would allow undercuts. I would also like to see a twisting
call where the base remained the same but the HF was twisted as it got
higher.


Mick

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Hi Ron

This is fantastic!!!!

I've just got home and rendered a quick pic - it opens new doors and a whole
new chapter on HFs.

I just did not realize you could use a pic as a function, brilliant idea.

Thanks

PS will post some pics later

Post a reply to this message

On Fri, 9 Jul 1999 14:31:27 +0100, "Mick Hazelgrove"
<mha### [at] mindaswinternetcouk> wrote:

>I just did not realize you could use a pic as a function, brilliant idea.

Credit where it's due, Matthew Corey Brown (xenoarch) is responsible
for the pigment isosurface type.  His brilliant idea, not mine. :)

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