In article <37B21CF0.F2E8FBD9@enter.net>, Charles <cfu### [at] enternet> wrote:
>There are two approaches to this problem, depending on the look the
:
>with each level anyway... or make a map of a single row of bricks 
>and fit this to each in a stack of cylinders which just happen to 
>get smaller near the top, making it more like a pseudo-cone out of 
>ever narrowing rings of bricks, which to my mind would look more 

The internal brick pattern in POV won't work radially will it? I'd have to use 
some sort of mapping (image, pattern, etc) wrapped around the cone/cylinder, 
right?

I'm thinking one image (a row of stones) could be mapped onto a cone that was 
just the height of the image and then scale the image around the 
circumfrance <SP?> of the cone for each row, between that and some rotation it 
should stagger the stones and the incline on the cone wouldn't be so steep as 
to distort the image too badly.

Using cylinders would be more accurate, but softening the edges around the 
stones would be a mess, then again, I'd have to test-render it, the hard edge 
might not even show up in a final render.

The bricks on a cone I think I'll just not worry about now, I think I've 
decided on stucco as a finish (once I perfect it), kind of a painted rough 
surface with hairline cracks in it. It's for a lighthouse, many (most) are 
painted brick... Stucco I think would be an acceptable finish for it.

PHIL

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On Wed, 11 Aug 1999 19:42:05 -0500, Chris Huff
<Chr### [at] compuservecom> wrote:

>Sure, any transform can be applied to an image map-including a matrix.

That is correct, but I think what Ken has in mind is 'shear the
image_map towards the cone axis so that it is not distorted upon
mapping.' I might be wrong and probably am.

Anyway, can conical mapping be achieved by means of uv-mapping a
simple linear_spline lathe?


Peter Popov
ICQ: 15002700

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>shear the image_map towards the cone axis so that it is not distorted
upon
mapping.?<

Well, that would be a distortion now, wouldn't it? :-)
Anyway, isn't the cylinderical mapping projected from the axis outward?
In that case, it will work on both cylinders and cones, and anything
that is radially symmetrical(is that the right term?) around that axis.
Of course, the image will appear stretched out of shape...but with
objects like cones, even UV mapping won't help.

>Anyway, can conical mapping be achieved by means of uv-mapping a
simple linear_spline lathe?<

Why not UV-map a cone?

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On Thu, 12 Aug 1999 06:52:01 -0500, Chris Huff
<Chr### [at] compuservecom> wrote:

<snip>
>Why not UV-map a cone?

Dunno... why indeed? Maybe because my first thought was that lathes
were among the first objects to support UV mapping in Nathan's patch.


Peter Popov
ICQ: 15002700

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Peter Popov wrote:
> 
> On Thu, 12 Aug 1999 06:52:01 -0500, Chris Huff
> <Chr### [at] compuservecom> wrote:
> 
> <snip>
> >Why not UV-map a cone?
> 
> Dunno... why indeed? Maybe because my first thought was that lathes
> were among the first objects to support UV mapping in Nathan's patch.
> 
> Peter Popov
> ICQ: 15002700

I thought it was bicubic patches -- ????

-- 
Ken Tyler

See my 700+ Povray and 3D Rendering and Raytracing Links at:
http://home.pacbell.net/tylereng/index.html

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In article <37B2B55E.5B5F6013@compuserve.com>, Chris Huff <Chr### [at] compuservecom>
wrote:
>>Anyway, can conical mapping be achieved by means of uv-mapping a
>simple linear_spline lathe?<
>
>Why not UV-map a cone?

Forgive my ignorance, but what is UV mapping?

PHIL

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Philip Bartol <phi### [at] removemeconcentricnet> wrote:
: Forgive my ignorance, but what is UV mapping?

  Take a texture and define three points in it. Now assign those three
points to the vertices of a triangle. With uv-mapping the triangle will
be textured with the texture which is inside the texture triangle defined
by those three points, no matter what's the shape or orientation of the
triangle. Those three points in the texture are uv-coordinates.
  See http://nathan.kopp.com/uv.htm for more examples.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):5;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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Doesn't matter anyway, I just checked and cones are not supported yet.
You would have to use a simple sor.

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On Wed, 11 Aug 1999 18:56:44 -0500, Chris Huff
<Chr### [at] compuservecom> wrote:

>What would this conical mapping be like? I think it would be exactly the
>same as cylinderical(You can't wrap a rectangular image around a cone
>without distortion.).
>
Conical mapping - given that textures (btimpas at least) come in 1*1
squares... would conical mapping use one half (triangular) of said 1*1
texture? Of course for bricks and the like the texture would ahve to
be pre-tilted by, oh, about 45%... but (offhand) it sounds like a
plausable approach. Looking beyond a 1*1 basic texture (halved) or to
a third dimension is beyond me - this just seemd like the "obvious"
way of doing conical textures.


Cheers,

Cliff Bowman
Why not pay my 3D Dr Who site a visit at http://www.who3d.cwc.net/
PS change ".duffcom" to ".net" if replying via e-mail

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