I've got two projects (just for starters) that would use stone or brick on 
non-flat surfaces...

I was thinking a bitmap wrapped around a cylinder should work (with a little 
bump mapping) but both projects I have in mind are conical rather than 
cylindrical.

On the slanted surface of a cone the image should get stretched or squished 
right?

The current project would be painted brick (if I don't just go with a stucco 
surface), but the other project would be stone. I've seen a tutorial on the 
web for creating good looking stone textures, but I'm not sure how they would 
work for a slanted surface.

Along the same lines I also have a cone shaped roof that I would like to tile, 
but I may be changing the cone roof to a dome of glass, so that might not be 
an issue (but the other project it will be, so I still would like to know how 
to do that also).

Any help in pointing me in the right direction would be great....

Thanks in advance.

PHIL

-----[ to reply, the domain name is "concentric.net" ]-----
Spelling mistakes brought to you courtesy of the
Allentown Public School System.

Post a reply to this message

Probably an image map with the bricks at the top larger in width than
the ones at the bottom would be the best idea. There is no way to escape
the distortion effect, other than to distort the image first so that it
looks right.

Post a reply to this message

This type of problem has been brought up plenty of times. I think it is time to
add conical mapping, just like we have spherical, cylindrical, and boxed. Can this
be done?

--
Anthony L. Bennett
http://welcome.to/TonyB

Non nova, sed nove.

Post a reply to this message

In article <37B1545F.EE910B4F@compuserve.com>, Chris Huff <Chr### [at] compuservecom>
wrote:
>Probably an image map with the bricks at the top larger in width than
>the ones at the bottom would be the best idea. There is no way to escape
>the distortion effect, other than to distort the image first so that it
>looks right.

I'll have to give it a try, but I'm not sure how well that'll look... maybe I 
should just model each piece of stone... hmmm...

<GRIN>

PHIL

-----[ to reply, the domain name is "concentric.net" ]-----
Spelling mistakes brought to you courtesy of the
Allentown Public School System.

Post a reply to this message

Here's a simple tiled roof

#macro Make_Tiles(NTiles,Height,Rad,Rot,Peak)
  #local dTheta = 360/NTiles;
  #local Pt1 = vrotate(<0,Height,Rad>,dTheta/2*y);
  #local Pt2 = <-1,1,1>*Pt1;
     union{
       #local T=0;
       #while(T<360)
           triangle{Pt1,Peak,Pt2 rotate T*y}
           cylinder{Pt1,Peak,0.05 rotate y*T}
       #declare T = T + dTheta;
     #end
    rotate y * Rot
  }
#end

#declare Roof = union{
Make_Tiles(16, -1, 1.325, 0, 0)
Make_Tiles(16, -2, 2.325, 360/16/2, y*-0.15)
Make_Tiles(16, -3, 3.250, 0, y*-0.35)
Make_Tiles(16, -4, 4.250, 360/16/2, y*-0.95)
Make_Tiles(16, -5, 5.30, 0, y*-1.65)
pigment{color rgb<.37,.62,.62>}
file://normal {wrinkles scale 0.25}
normal{facets  coords .75}
finish{crand 0.2 specular 0.5 }
}

With thanks to Dan Connelly

Hope this is of some use.

Mick


Philip Bartol <phi### [at] REMOVEMEconcentricnet> wrote in message
news:37b125ba@news.povray.org...
> I've got two projects (just for starters) that would use stone or brick on
> non-flat surfaces...
>
> I was thinking a bitmap wrapped around a cylinder should work (with a
little
> bump mapping) but both projects I have in mind are conical rather than
> cylindrical.
>
> On the slanted surface of a cone the image should get stretched or
squished
> right?
>
> The current project would be painted brick (if I don't just go with a
stucco
> surface), but the other project would be stone. I've seen a tutorial on
the
> web for creating good looking stone textures, but I'm not sure how they
would
> work for a slanted surface.
>
> Along the same lines I also have a cone shaped roof that I would like to
tile,
> but I may be changing the cone roof to a dome of glass, so that might not
be
> an issue (but the other project it will be, so I still would like to know
how
> to do that also).
>
> Any help in pointing me in the right direction would be great....
>
> Thanks in advance.
>
> PHIL
>
> -----[ to reply, the domain name is "concentric.net" ]-----
> Spelling mistakes brought to you courtesy of the
> Allentown Public School System.

Post a reply to this message

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.).

Post a reply to this message

Chris Huff 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.).

Hmmm... I wonder if you can sheer an image map... If I didn't have this
69 day render in process I would check it out myself.

-- 
Ken Tyler

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

Post a reply to this message

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

Post a reply to this message

Chris Huff 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.).

Yup, that sounds about right. Like trying to map a rectangular image
onto a sphere and wanting to avoid it getting pinched at the poles.
Cylindrical or conical mapping; Either way, it's gotta come to a 
point somewhere if its on a cone.

There are two approaches to this problem, depending on the look the
poster wants... either accept that the map is going to shrink near
the top... a geometrically conical stack of bricks would have to 
have each brick cut to narrow approaching the top, and get smaller 
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 
like what you'd be most likely to do if you were really trying to 
shape bricks into such a structure. 

Charles
-- 
http://www.enter.net/~cfusner
"...Then darkness took me, and I strayed out of thought and time,
 and I wandered far on roads that I will not tell..." 
                              -The Two Towers, JRR Tolkien

Post a reply to this message

In article <37b1e99a@news.povray.org>, "Mick Hazelgrove"
<mha### [at] mindaswinternetcouk> wrote:
>Here's a simple tiled roof
:
>With thanks to Dan Connelly
>
>Hope this is of some use.

I'll have to give it a render to see what it does, I've got an idea from 
looking at the code, but....

Thanks, I'll let you know how it works out...

PHIL

-----[ to reply, the domain name is "concentric.net" ]-----
Spelling mistakes brought to you courtesy of the
Allentown Public School System.

Post a reply to this message

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

-----[ to reply, the domain name is "concentric.net" ]-----
Spelling mistakes brought to you courtesy of the
Allentown Public School System.

Post a reply to this message

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

Post a reply to this message

>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?

Post a reply to this message

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

Post a reply to this message

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

Post a reply to this message

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

-----[ to reply, the domain name is "concentric.net" ]-----
Spelling mistakes brought to you courtesy of the
Allentown Public School System.

Post a reply to this message

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 -*/

Post a reply to this message

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

Post a reply to this message

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

Post a reply to this message