I've never really used lathe objects all that much, and am getting a bit
confused...

I've created the lathe as shown below, and as I always thought lathes were
"solid" I was surprised that I could look down the middle of it.

I realise (I think) that I could add a point at <0,0> and <0, 56>, but then
cutting a hole in the side would still reveal the hollow nature of the
shape...

Have I missed something obvious?  If I've got it wrong (surely not ;) then
how can I create a solid shape?  Would I need to double back with the
spline-points outlining the shape?

  lathe{linear_spline 8
    <25.0, 56.0>,
    <24.0, 55.8>,
    <24.0, 31.5>,
    <23.0, 31.5>,
    <23.0, 24.0>,
    <16.0, 17.0>,
    <16.0,  0.2>,
    <17.0,  0.0>
    pigment{color rgb 0.5}
  }

Post a reply to this message

On Sun, 8 Sep 2002 20:09:46 +0100, "Mark Hanford"
<mar### [at] theinternetcom> wrote:

>I realise (I think) that I could add a point at <0,0> and <0, 56>, but then
>cutting a hole in the side would still reveal the hollow nature of the
>shape...

For starters, try it and see what happens. You might be surprised :)

Next, read section 9.1.1.9 of the manual: "How do I make an object
hollow?" If that still doesn't help, don't hesitate to ask for help -
that's what these groups are for.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

Post a reply to this message

"Peter Popov" <pet### [at] vipbg> wrote in message
news:919nnusifmjg1ab5ccaiskdnnlqnm549gh@4ax.com...
> On Sun, 8 Sep 2002 20:09:46 +0100, "Mark Hanford"
> <mar### [at] theinternetcom> wrote:
>
> >I realise (I think) that I could add a point at <0,0> and <0, 56>, but
then
> >cutting a hole in the side would still reveal the hollow nature of the
> >shape...
>
> For starters, try it and see what happens. You might be surprised :)

OOOoooohhh.  I see...

That's clever - so I guess that if the spline is "closed" to <0,*> then the
shape becomes "solid"...


>
> Next, read section 9.1.1.9 of the manual: "How do I make an object
> hollow?" If that still doesn't help, don't hesitate to ask for help -
> that's what these groups are for.
I understand (I think) the concept of hollowness wrt POV, your first
suggestion was spot-on.  I wanted to CSG out of the lathe object and for it
to appear solid, not like a shell...


>
>
> Peter Popov ICQ : 15002700
> Personal e-mail : pet### [at] vipbg
> TAG      e-mail : pet### [at] tagpovrayorg

Post a reply to this message

In article <3d7bac5b$1@news.povray.org>,
 "Mark Hanford" <mar### [at] theinternetcom> wrote:

> That's clever - so I guess that if the spline is "closed" to <0,*> then the
> shape becomes "solid"...

No, that just makes the shape closed. Lathes are always solid, they just 
can have open parts on their surface.

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

Post a reply to this message

"Christopher James Huff" <chr### [at] maccom> wrote in message
news:chr### [at] netplexaussieorg...
> In article <3d7bac5b$1@news.povray.org>,
>  "Mark Hanford" <mar### [at] theinternetcom> wrote:
>
> > That's clever - so I guess that if the spline is "closed" to <0,*> then
the
> > shape becomes "solid"...
>
> No, that just makes the shape closed. Lathes are always solid, they just
> can have open parts on their surface.
Sorry, I didn't mean solid in the POV sense, but in the "real-world/visual"
sense.

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

Post a reply to this message

Mark Hanford <mar### [at] theinternetcom> wrote:
> Sorry, I didn't mean solid in the POV sense, but in the "real-world/visual"
> sense.

  Pretty impossible to do with raytracing. Raytracing can only handle
surfaces.
  Which is enough for practically 100% of what you want to do... :)

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -

Post a reply to this message

"Warp" <war### [at] tagpovrayorg> wrote in message
news:3d7bc6b1@news.povray.org...
> Mark Hanford <mar### [at] theinternetcom> wrote:
> > Sorry, I didn't mean solid in the POV sense, but in the
"real-world/visual"
> > sense.
>
>   Pretty impossible to do with raytracing. Raytracing can only handle
> surfaces.

It seems to cope quite well though!  It also "idiot-proofs" most of the
whole surface/solid thing.  I'd have given up ages ago if I had to put a
surface on every bit I CSG'd away just to make a thing look
"solid-but-with-a-hole-through-it"...

>   Which is enough for practically 100% of what you want to do... :)
The sad fact for me is that I know that POV can do the things I want - I've
only got to look at p.b.i and irtc (and of course your own work ;) to know
that - it's getting it to do them that stumps me!

>
> --
> #macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb
M()}}
> N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
> N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  -
Warp -

Post a reply to this message