Hi there.

I am trying to create an image with an (ant)arctic-looking landscape - much
like Christoph Hormann's image here:
http://www.imagico.de/pov/pict/frozen_island.jpg.

However, I just cannot work out how to get the texturing right.

My height field is created using a "f_ridged_mf" function, and I have tried
using a texture consisting of a slope texture map of snow and rock. The
effect is far from what I am after -

The main problem appears to be that the "slope" keyword is too "dependent"
on altitude. Whereas Christoph's image above has snow / rock together at a
range of altitudes, I get a very clear "cutoff point" with snow below and
rock below.

If anyone have any pointers to this, or know of any tutorials on how to
texture landscapes in general, I am very grateful.

Thanks in advance!

Post a reply to this message

Kjetil wrote:
> Hi there.
> 
> I am trying to create an image with an (ant)arctic-looking landscape - much
> like Christoph Hormann's image here:
> http://www.imagico.de/pov/pict/frozen_island.jpg.
> 
> However, I just cannot work out how to get the texturing right.
> 
> My height field is created using a "f_ridged_mf" function, and I have tried
> using a texture consisting of a slope texture map of snow and rock. The
> effect is far from what I am after -
> 
> The main problem appears to be that the "slope" keyword is too "dependent"
> on altitude. Whereas Christoph's image above has snow / rock together at a
> range of altitudes, I get a very clear "cutoff point" with snow below and
> rock below.
> 
> If anyone have any pointers to this, or know of any tutorials on how to
> texture landscapes in general, I am very grateful.
> 
> Thanks in advance!
> 
> 


I usually pre-define substrate textures using a gradient y for altitude 
dependent features, then combine those into a new texture using slope to 
determine which are visible,  i.e.;  (sorry, not on my machine so don't 
have any available at the moment, so pure pseudo-code here...)

T_Snow {
   gradient y
   map
     [LOW   wet_mud ]
     [MID   patchy_drifts ]
     [HIGH  packed_powder ]
}
T_Rock {
   gradient y
   map
     [LOW   gravel ]
     [MID   mixed_scree ]
     [HIGH  hard_stone ]
}

T_Rocky_Snow
   slope y
   map
     [STEEP  T_Rock ]
     [FLAT   T_Snow ]
}

That way both the snow and rock will change with slope and altitude. 
Just remember that your y scale must always be the same as the 
height_field so the gradient y doesn't tile itself. I usually apply the 
texture to the height_filed before scaling so they always stay the same.

RG

Post a reply to this message

What is the best way to texture a object.

Here is the code:

#include "colors.inc"
#include "textures.inc"
#include "skies.inc"


camera {
        location <-70,40,-150>
        angle 45
        look_at <27.5,41,0>
}

light_source { <-1000,500,200> White }
background {White}

difference {
        box { <20, 0, -15>, <21, 65, -30> }
        box { <19, 51, -20>, <22, 58, -25> }
        texture {
        pigment{ image_map { jpeg "stone01.jpg" } }
        }
}

//right, front wall
box {
        <20, 0, -29>, <30, 65, -30>
        texture {
        pigment{ image_map { jpeg "stone01.jpg" } }
        }
        }

It just seems that the box is not textured properly, how can I make it
realistic?

Post a reply to this message

"Prodan" <nomail@nomail> wrote in message 
news:web.44153ba2f111dca5ef7b24140@news.povray.org...
> What is the best way to texture a object.
>

Hi Prodan,
There are lots of ways and I'm not sure there is necessarily a best way.


> Here is the code:
>
> ... snip ...
>
> difference {
>        box { <20, 0, -15>, <21, 65, -30> }
>        box { <19, 51, -20>, <22, 58, -25> }
>        texture {
>        pigment{ image_map { jpeg "stone01.jpg" } }
>        }
> }
>

I would guess you are starting from a photograph in the file 'stone01.jpg'. 
This can give reasonable results with some photos, but is a bit fiddly as it 
works best when the viewing angle and lighting in the rendered image match 
those with which the photo was taken and this can be difficult to achieve.
One problem with your example is that the surface of the box is flat and the 
edges are sharp. This immediately tells the eye that it's not a real stone 
surface.
Another problem is that, when the image repeats vertically and horizontally 
you may well see the joins.

>  ... snip ...
>
> It just seems that the box is not textured properly, how can I make it
> realistic?
>

One way is of using image maps is illustrated on my site at 
http://www.telinco.co.uk/c_bartlett/povray/stonecol/stonecol.htm.
It's a bit old and may need some changes for running in the current version 
of POV-Ray. Nevertheless, the source still may serve as an example.
This uses an image map for the stone colours and a second image map to 
control a height field that gives a profile to the surface.
To hide the joins at the edges of the image, these images have been adapted, 
so that the left-hand edge matches the right-hand edge and the top-edge 
marries up with the bottom-edge.

Hope this gives you some ideas.
Regards,
Chris B.

Post a reply to this message

How odd.

Earlier I made a reply to gonzo (to say thanks, it works!), but that seems
to have disappeared, or not made it to the thread...

This newsgroup isn't moderated, is it?

Post a reply to this message

Kjetil wrote:
> How odd.
> 
> Earlier I made a reply to gonzo (to say thanks, it works!), but that seems
> to have disappeared, or not made it to the thread...
> 
> This newsgroup isn't moderated, is it?
> 
> 
You're welcome, glad it worked!

Did you post from a newsreader or from your browser? Sometimes when I 
post from a newsreader I can't see my post in webview, but I just 
checked with both and I can't see your post either....

RG

Post a reply to this message