Actually, I'm not that dumb!  I'm a Maths undergraduate writing a report on
heat transfer.  I need a fairly simple illustration of a tea urn
(commercial catering water boiler).

The tea urn is made of 1 layer of stainless steel and then 1 layer of
polypropylene.

I tried to draw some cylinders but they seem to have zero width.  I could
not find a way to draw cylinders with a substantial width.

Can anyone please help?

Kind regards,
Jenny Page

email: jen### [at] hotmailcom

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> I tried to draw some cylinders but they seem to have zero width.  I could
> not find a way to draw cylinders with a substantial width.
> 

Look up difference in the povray documentation.

difference {
    cylinder
    {
       <0,0,0>,
       <0,1,0>,
       1
       pigment { color rgb <1,0,0> } //red
    }
    cylinder
    {
       <0,0.5,0>,
       <0,1.1,0>,
       0.5
       pigment { color rgb <0,0,1> } //blue
    }
}

This code would make a cylinder with a cylinderial piece cut out of it. 
  The second one is what is cut out of the first one.  You can have as 
many shapes cut out of the first shape.
If you need more help you can always ask.

Brendan

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did you specify a radius? it comes right after the second coordinate

"JennyPage" <jen### [at] hotmailcom> wrote in message
news:web.3d62b6ee2ffea3e6ee5540370@news.povray.org...
> Actually, I'm not that dumb!  I'm a Maths undergraduate writing a report
on
> heat transfer.  I need a fairly simple illustration of a tea urn
> (commercial catering water boiler).
>
> The tea urn is made of 1 layer of stainless steel and then 1 layer of
> polypropylene.
>
> I tried to draw some cylinders but they seem to have zero width.  I could
> not find a way to draw cylinders with a substantial width.
>
> Can anyone please help?
>
> Kind regards,
> Jenny Page
>
> email: jen### [at] hotmailcom
>

Post a reply to this message

In article <web.3d62b6ee2ffea3e6ee5540370@news.povray.org>,
 "JennyPage" <jen### [at] hotmailcom> wrote:

> Actually, I'm not that dumb!  I'm a Maths undergraduate writing a report on
> heat transfer.  I need a fairly simple illustration of a tea urn
> (commercial catering water boiler).
> 
> The tea urn is made of 1 layer of stainless steel and then 1 layer of
> polypropylene.
> 
> I tried to draw some cylinders but they seem to have zero width.  I could
> not find a way to draw cylinders with a substantial width.

By "width", do you mean thickness of the cylinder wall?
Shape surfaces are infinitely thin in POV, if you are using cylinders 
with "open" or "clipped_by" to remove the end caps you will get a single 
surface instead of a thick sheet. If you want a tube with some thickness 
to the walls, you should use a CSG difference of two cylinders:

difference {
    cylinder {< 0, 0, 0>, < 0, 1, 0>, 0.5}//the main cylinder
    //Cut out the center to leave a tube
    cylinder {< 0,-0.001, 0>, < 0, 1.001, 0>, 0.4}
}

Notice that the end points are slightly outside the main cylinder, this 
is to avoid precision errors where the surfaces would coincide.

If the polypropylene is thin enough that you can't see its thickness, 
you could get away with just texturing the inside differently. In that 
case, just give the first cylinder a stainless steel texture, and the 
second cylinder a polypropylene texture.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

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