Hello Group

I have built a scene including a house (prism) , and I would like to cover 
the prism with rusty corrugated sheet metal, or even painted sheet metal. 
Is there an easy way to do this, or do I hve to model the bumps on the 
corrugated sheet metal, which will be painfully slow?

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hairball nous apporta ses lumieres ainsi en ce 2004-11-30 17:25... :

>Hello Group
>
>I have built a scene including a house (prism) , and I would like to cover 
>the prism with rusty corrugated sheet metal, or even painted sheet metal. 
>Is there an easy way to do this, or do I hve to model the bumps on the 
>corrugated sheet metal, which will be painfully slow?
>
A difference of two identical blobs, one of whitch is translated a small 
amount down, may be what you are looking for. The blobs are made of a 
serie of cylinder components. Intersect it with a box to get straight edges.
Other than that, you may try a parametric or an issosurface. A marble 
base pattern using a cubic_wave to have smooth curves, it should have a 
fairly low max_gradient making it relatively fast.
Once you have your sheet, just add some texture to it.

Alain

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Alain wrote:

> A difference of two identical blobs, one of whitch is translated a small 
> amount down, may be what you are looking for. The blobs are made of a 
> serie of cylinder components. Intersect it with a box to get straight 
> edges.
> Other than that, you may try a parametric or an issosurface. A marble 
> base pattern using a cubic_wave to have smooth curves, it should have a 
> fairly low max_gradient making it relatively fast.
> Once you have your sheet, just add some texture to it.

Heh heh, once again the POV newsgroup anticipates my question before I 
even ask it!

I got a very nice *new* piece of sheetmetal by using a thin sphere_sweep 
scaled on one axis to make the sheet, but I wanted to make one that's 
warped and bent.  Your blob idea should work well.

I thought of isosurface but don't have a clue where to start. Guess I'm 
"isochallenged".

RG

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"hairball" <rwb### [at] spaminterchangeubcca> wrote in message
news:41acf362$1@news.povray.org...
> Hello Group
>
> I have built a scene including a house (prism) , and I would like to cover
> the prism with rusty corrugated sheet metal, or even painted sheet metal.
> Is there an easy way to do this, or do I hve to model the bumps on the
> corrugated sheet metal, which will be painfully slow?

I wasn't sure if by "model the bumps" you meant model the bumps caused by
the rust, or whether you just meant the shape of the corrugated iron.

If the former, you could add either a noise function or a pigment function
to the following code below.

If the latter, an isosurface can do this very easily (and quickly):

#version 3.6;

#include "colors.inc"

camera {
  location  <0.0, 25.0, -50.0>
  look_at   <0.0, 0.0,  0.0>
}

light_source {
  <0, 0, 0>            // light's position (translated below)
  color rgb <1, 1, 1>  // light's color
  translate <-30, 30, -30>
}

// ----------------------------------------

#declare Thickness = 0.1;
#declare Corr_Iron = function(x,y,z)
{
 abs(y-cos(x))-(Thickness/2)
}

isosurface {
  function { Corr_Iron(x, y, z) }
  contained_by { box {<-15,-2,-25>,<15,2,25>} }
  accuracy 0.001
  max_gradient 4
 pigment{Gray20}
}

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