Can anyone point me towards creating a decent looking brick arch? I did 
try using a radial bump map and a high frequency. While it looked quite 
funky, it wasn't what I was looking for. Is there a way to take an 
existing texture and bend it?

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Shawn wrote:
> 
> Can anyone point me towards creating a decent looking brick arch? I did
> try using a radial bump map and a high frequency. While it looked quite
> funky, it wasn't what I was looking for. Is there a way to take an
> existing texture and bend it?

Real POVer's do is with real 3D objects, lovingly placed by hand, and
textured individually for added realism.

--
Ken Tyler

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Gee your a big help! I was hoping to be lazy!
(now where's me darned trowel....)

Ken wrote:

> 
> Shawn wrote:
> 
>> Can anyone point me towards creating a decent looking brick arch? I did
>> try using a radial bump map and a high frequency. While it looked quite
>> funky, it wasn't what I was looking for. Is there a way to take an
>> existing texture and bend it?
> 
> 
> Real POVer's do is with real 3D objects, lovingly placed by hand, and
> textured individually for added realism.
> 
> --
> Ken Tyler

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Shawn wrote:
> 
> Gee your a big help! I was hoping to be lazy!
> (now where's me darned trowel....)

I suppose if you are feeling hopelessly lazy you could search on the
net for a picture of a brick arch and just (shudder!!!) image map it
onto the surface of your choice....but that would be cheating and
you would never have the same satisfaction of doing it like a real
POVer would....and....and....

-- 
Ken Tyler

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Well, ok, I have occasionaly stooped to using an image map or two...(but 
I was forced to by savages! Honest!!) But I was hoping to make something 
worthy of close inspection...at least from 50 paces with an eyepatch?
Ken wrote:

> 
> Shawn wrote:
> 
>> Gee your a big help! I was hoping to be lazy!
>> (now where's me darned trowel....)
> 
> 
> I suppose if you are feeling hopelessly lazy you could search on the
> net for a picture of a brick arch and just (shudder!!!) image map it
> onto the surface of your choice....but that would be cheating and
> you would never have the same satisfaction of doing it like a real
> POVer would....and....and....

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This might or might not help you (probably not):

#declare Th= function{"TH"}
isosurface {
       function { ((z*z+y*y-1.5*1.5)
                  &-(z*z+y*y-1.3*1.3)
                  &abs(x)-0.35)
                  -0.03*GraniteFun(x*3,y*4,z*3)
                  +(0.095-(max(((Th(y,x,z)/4)%0.1),0.095)))*2
                }

        method 2
        //eval
        max_gradient 5

        accuracy 0.001
        contained_by{box {<-0.5,0,-1.6>,<0.5,1.6,1.6>}}

        pigment{....
              }

    }

Remove the GraniteFun-Stuff with whatever displacement you want.

To curve an existing texture declare a pigment-function and use it with some
math as a function-pigment ... if you get what I mean ;-)

Marc-Hendrik


Shawn schrieb in Nachricht <3AE### [at] orthancabca>...
>Can anyone point me towards creating a decent looking brick arch? I did
>try using a radial bump map and a high frequency. While it looked quite
>funky, it wasn't what I was looking for. Is there a way to take an
>existing texture and bend it?
>

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Ken <tyl### [at] pacbellnet> wrote:
: Real POVer's do is with real 3D objects, lovingly placed by hand, and
: textured individually for added realism.

  Real POVer's do it with #whiles :)

-- 
#local D=array[6]{11117333955,7382340,3358,3900569407,970,4254934330}
#local I=0;#macro M()<mod(D[I],13)-6,mod(div(D[I],13),8)-3,10>#end
#while(I<6)cylinder{M()#local D[I]=div(D[I],104);M().1
pigment{rgb M()}}#local I=(D[I]>99?I:I+1);#end              /*- Warp -*/

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Shawn <sha### [at] orthancabca> wrote:

> Can anyone point me towards creating a decent looking brick arch? I did 
> try using a radial bump map and a high frequency. While it looked quite 
> funky, it wasn't what I was looking for. Is there a way to take an 
> existing texture and bend it?

If all you want to do is texture it, you can use the following function:

function { funct(sqrt(x*x+y*y), atan2(y,x), z) }

This bends a section of the xy plane around the origin. Funct can be any
pigment function you like. This would allow, for example, you to use a
gradient to create radial stripes, but also allows for stranger things. 
Applied correctly, you should be able to create your arch.

Note that as the distance from the origin gets larger, the texture is going
to scale up.  This shouldn't be too much of a problem for what you're doing.

The other option is to create individual objects.  Using the same function
and a rounded cube iso (or any other iso for that matter), you can create
bricks that are curved.

Geoff

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Ah I can hear the voices of my fore-fathers crying out..."RTFM! RTFM!" I 
think I'll experiment with both suggestions, and well as Marcs. I think 
an isosurface would likely make more sense for what I want to do.
Might even post the result on p.b.images and see if it weathers the 
cannonade. :-)

Thanks!
Shawn

Geoff Wedig wrote:


> If all you want to do is texture it, you can use the following function:
> 
> function { funct(sqrt(x*x+y*y), atan2(y,x), z) }
> 
> This bends a section of the xy plane around the origin. Funct can be any
> pigment function you like. This would allow, for example, you to use a
> gradient to create radial stripes, but also allows for stranger things. 
> Applied correctly, you should be able to create your arch.
> 
> Note that as the distance from the origin gets larger, the texture is going
> to scale up.  This shouldn't be too much of a problem for what you're doing.
> 
> The other option is to create individual objects.  Using the same function
> and a rounded cube iso (or any other iso for that matter), you can create
> bricks that are curved.
> 
> Geoff

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Shawn <sha### [at] orthancabca> wrote:

> Ah I can hear the voices of my fore-fathers crying out..."RTFM! RTFM!" I 
> think I'll experiment with both suggestions, and well as Marcs. I think 
> an isosurface would likely make more sense for what I want to do.
> Might even post the result on p.b.images and see if it weathers the 
> cannonade. :-)

Well, this sort of reparameterization isn't in the manuals, really.  It's
something I've kinda worked out by banging my head against it for awhile. 
Reparameterization functions can be really nice *if* you can work out the
equations to transform the basic xyz coordinants where you want, and *if*
you have the processor time to llet it (they can be slow)

Isos are probably the best bet in this case, as they give the greatest
control, but they're also the trickiest to work with.  I've had some luck
with making stone and brick shapes with isos (look at the posts under Door
into Summer and also Into the Abyss.  Both use re-parameterized rounded cube
isos to get the stonework)  I imagine you can get something similar.

Geoff

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