Hello,
I have a surface that I've applied a uv mapping to but I cannot get it to
have a bumpy texture.  An example bitmap can be viewed at
http://xenomechanics.com/plate_gallery/temp.html
The code is extensive as it's a mesh2 but texture portion is:

texture { uv_mapping pigment{ image_map { sys "xenoGraffitipad.bmp" } }
                     normal { bumps .1 scale 10 }
        }


In rendering the normal bumps are ignored.  The surrounding surfaces without
uv mapping  cited below is working fine
texture { pigment { color rgb <1,1,1> }
           normal { bumps bumpsA scale scaleA }
        }

The picture shows the uv mapped surface not blending well into the
surrounding bumpy surface.
Can someone tell me if I have made a mistake or if you just cannot have
simulated bumps using normal and UV mapping?
Thanks
Tony




xen### [at] xenomechanicscom

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web.3e03671f1e67b05f88d4e3910@news.povray.org...

>                      normal { bumps .1 scale 10 }

The uv surface is comprised between <0,0> and <1,1>.
If you scale the bumps by 10, it becomes much larger than that, which is why
you can't see it.
Try to scale it somewhere between 1/100 and 1/10 and see if it works.

G.


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Gilles,
The example in the documentation has it at
normal { bumps 0.4 scale 0.2 }
but it still ignores it and just renders it flat :(
Tony
xen### [at] xenomechanicscom

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The code below helps to simulate my problem.   The 1st (right) sphere is
without bumps, the 2nd (left) does.

light_source {<0, 2, -3>,rgb <1,1,1> }
background { color rgb <1,1,1> }
light_source { <10, 100, -100> rgb <1,1,1> }
camera {  location <.25, .25, -5>  look_at  <.25, .25,  0>   }

sphere {<2, 1, 2>, 2  //right sphere
texture {   uv_mapping   pigment { color rgb <1,1,0> }     normal { bumps
0.4 scale 0.2 }}  }

sphere {<-2, 1, 2>, 2  //left sphere
texture { /*uv_mapping*/   pigment { color rgb <1,1,0> } normal { bumps 0.4
scale 0.2 }}  }

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Wasn't it Tony LaVigne who wrote:
>The code below helps to simulate my problem.   The 1st (right) sphere is
>without bumps, the 2nd (left) does.
>
>light_source {<0, 2, -3>,rgb <1,1,1> }
>background { color rgb <1,1,1> }
>light_source { <10, 100, -100> rgb <1,1,1> }
>camera {  location <.25, .25, -5>  look_at  <.25, .25,  0>   }
>
>sphere {<2, 1, 2>, 2  //right sphere
>texture {   uv_mapping   pigment { color rgb <1,1,0> }     normal { bumps
>0.4 scale 0.2 }}  }
>
>sphere {<-2, 1, 2>, 2  //left sphere
>texture { /*uv_mapping*/   pigment { color rgb <1,1,0> } normal { bumps 0.4
>scale 0.2 }}  }
>

But that is fixed by what Giles Tran said.

When the bumps are uvmapped, the scale of the bump is relative to the
scale of the uvmapping cell instead of relative tot he unit cube.
Changing the scale from 0.2 to 0.02 fixes it.

-- 
Mike Williams
Gentleman of Leisure

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Mike Williams wrote:
>Wasn't it Tony LaVigne who wrote:
>>The code below helps to simulate my problem.   The 1st (right) sphere is
>>without bumps, the 2nd (left) does.
>>
>>light_source {<0, 2, -3>,rgb <1,1,1> }
>>background { color rgb <1,1,1> }
>>light_source { <10, 100, -100> rgb <1,1,1> }
>>camera {  location <.25, .25, -5>  look_at  <.25, .25,  0>   }
>>
>>sphere {<2, 1, 2>, 2  //right sphere
>>texture {   uv_mapping   pigment { color rgb <1,1,0> }     normal { bumps
>>0.4 scale 0.2 }}  }
>>
>>sphere {<-2, 1, 2>, 2  //left sphere
>>texture { /*uv_mapping*/   pigment { color rgb <1,1,0> } normal { bumps 0.4
>>scale 0.2 }}  }
>>
>
>But that is fixed by what Giles Tran said.
>
>When the bumps are uvmapped, the scale of the bump is relative to the
>scale of the uvmapping cell instead of relative tot he unit cube.
>Changing the scale from 0.2 to 0.02 fixes it.
>
>Mike Williams
>Gentleman of Leisure
>
I think I see now.  As I understand it I cannot get the bumps (using
normals)  larger than the uv Cell.
I appreciate the help.
Tony
xen### [at] xenomechanicscom

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