Hello !

i would like to know if it is possible to use uv mapping for file based height
fields ?

all i get is a stretched texture (long lines) on planar sections parallel to the
xz plane

here is the height field + texture i am trying to uv map (before uv map) :

height_field{ tga "input.tga" smooth water_level 0 double_illuminate
scale <166000,24000,166000>
translate<-83000,0,25000>
texture{
       pigment {
                bozo
  turbulence 0.92
                scale 5
                color_map {

                           [0.3  color Orange]
                           [0.7  color Brown]
                           [0.9  color Black]
                          }
               }
       normal  {

                crackle 0.75
                turbulence 0.25
                scale 0.36
                }
       }

           }

Thank you for any help !

I've seen this thread and thought it could help, but it does note reference file
based height fields...

http://news.povray.org/povray.binaries.scene-files/thread/%3C4d28409d@news.povray.org%3E/

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Am 22.04.2012 19:23, schrieb rodv92:

> i would like to know if it is possible to use uv mapping for file based height
> fields ?

You can always give it a try. I /think/ it works (despite not being 
mentioned in the docs), but I don't know for sure off the top of my hat.

> all i get is a stretched texture (long lines) on planar sections parallel to the
> xz plane

You can also use "warp { planar y }" at the end of the texture 
definition to pick a single slice of the texture in the xz plane and 
project that along the y axis onto your height field.

Post a reply to this message

On 22-4-2012 19:23, rodv92 wrote:
> Hello !
>
> i would like to know if it is possible to use uv mapping for file based height
> fields ?
>

Iirc, it should be possible, but I am unable to find again an example 
where I may have used it :-(

In the Insert Menu, under Special Shapes, there is this:

  // ----------------- HF_Square macro ------------------
#declare Fn_1 =
  function(x, y, z)
   {1-(-f_snoise3d(x*2,y*2,z*2)*0.25)}
// -----------------------------------------------------
object{ HF_Square( Fn_1, //Function,
                      0, // UseUVheight:  0 or 1
                      1, // UseUVtexture: 0 or 1
                <50,50>, // Resolution,
                      1, // Smooth: 0 or 1
                      "",// FileName, ""=no file,
            <-1,0,-1>*2, //MnExt,
            <1,1,1>*2    //MxExt
                       ) //------------------------------
   texture{ pigment{ checker
                     color rgb<1,0.6,0>
                     color rgb<1,1,1>*0.9
                     scale 0.05}
            finish { phong 0.1}
          } // end of texture
   scale<1,1,1>*1
   rotate<0,0,0>
   translate<0,-1.5,0>
} // end of HF_Square ----------------------------------

Could this help you?

Thomas

Post a reply to this message

> Hello !
>
> i would like to know if it is possible to use uv mapping for file based height
> fields ?
>
> all i get is a stretched texture (long lines) on planar sections parallel to the
> xz plane
>

The height field is set along the x-z plane while your image is initialy 
mapped on the x-y plane.

You need to rotate 90*x so that it extend in the correct direction.
After the rotation of the image, the hight_field sit in a box extending 
from <0,0,0> to <1,1,1> and the image in a tile from <0,0,0> to <1,0,1> 
extending infinitely along the y axis.

Also, it would be beter to apply it before you scale the hight_field. 
That way, the two will be affected at once, and will probably make the 
UV mapping un-needed.


Alain

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On 24-4-2012 21:59, Alain wrote:
> The height field is set along the x-z plane while your image is initialy
> mapped on the x-y plane.
>
> You need to rotate 90*x so that it extend in the correct direction.
> After the rotation of the image, the hight_field sit in a box extending
> from <0,0,0> to <1,1,1> and the image in a tile from <0,0,0> to <1,0,1>
> extending infinitely along the y axis.

Yes, this is the thing to do when applying an image_map to a 
height_field. However...

>
> Also, it would be beter to apply it before you scale the hight_field.
> That way, the two will be affected at once, and will probably make the
> UV mapping un-needed.

The interesting question here is if uv_mapping is possible on 
height_fields. With the method described and (e.g.) a strong vertical 
scaling, the image_map gets distorted along the flanks of 
mountains/valleys. Am I correct to guess that this would not be the case 
when applying uv_mapping? However, adding uv_mapping results in banding. 
My tentative conclusion would be that uv_mapping is indeed not 
implemented for height_fields, as already shown by its absence in the 
documentation (par. 3.5.7.1 Supported Objects).

Thomas

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