One day while looking for something realistic to render, I thought of
making a modell train scene. I ended up wanting to create a series of
include files that could be used to make both model trains and real
trains (with some modification). So I made an include file for the
tracks. The problem is that I can make the straight peices, but the real
model curve peices are hard to modell using CSG, and I was hoping
someone could help me find a better way.

I made the peices by declaring dimensions for the metal peices, etc. For
the curve, I used CSG differences to make
the wires from cylinders. I'm including the code with this, so someone
can get an idea.

If there is any person that has made a model train include file, I would
like to see if (and refine my own file), so if you could direct me to a
source, that would work too.

Thanks a bunch,

Tim Soderstrom

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Attachments:
Download 'train.zip' (3 KB)

Tim Soderstrom wrote:
> 
> One day while looking for something realistic to render, I thought of
> making a modell train scene. I ended up wanting to create a series of
> include files that could be used to make both model trains and real
> trains (with some modification). So I made an include file for the
> tracks. The problem is that I can make the straight peices, but the real
> model curve peices are hard to modell using CSG, and I was hoping
> someone could help me find a better way.
> 
> I made the peices by declaring dimensions for the metal peices, etc. For
> the curve, I used CSG differences to make
> the wires from cylinders. I'm including the code with this, so someone
> can get an idea.
> 
> If there is any person that has made a model train include file, I would
> like to see if (and refine my own file), so if you could direct me to a
> source, that would work too.
> 
> Thanks a bunch,
> 
> Tim Soderstrom

  I am not aware of any model train include files available but I may
have a suggestion that will bail you  out of your curent delimma. As
recently as one month ago there were 2 different extrusion macros
posted to the povray.binaries.utilities group.
  The macros takes a defined shape, in this case a cross section of
track, along with a set of points describing a path to take, in this
case the rail bed, and the macro will then extrude your shape along
the path from the start to the end point. I can think of no easier
way to do this  except it inside of a modelling program. One thing
you should know is that the more points on a curve that you can
supply the macro with the smoother the resulting curves and tracks
will be. If you only feed it 4 points it will have some very sharp
bends. If you feed it 30 - 40 or more points it will be very smooth
as long as you don't stretch it out over many Pov units. A utility
tht can generate spline curves would be a big aid in establishing
the nessesary points to feed the macro. See the link below for a
program that might aid you in this regard.

Spline Editor:
http://www.flashnet.it/users/fn027571/spil/index.html

-- 
Ken Tyler

mailto://tylereng@pacbell.net

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I don't use Spline Editor - I use sPatch (both work well, but Spatch doesn't
require control points - its downfall, however, is that it cannot do pure
lathes - it converts them). I have considered using sPatch to make the curve,
but the problem is that I may want to add some detail to the track. If I used
sPatch, I would have to remodell the curuve. In any case, I will look for
that macro on twysted.net (as soon as it works again) and see if that will
help me. Really, the problem is not making the curve, it's getting the angle
of the cut right and converting this value to a rotation of a box. I may
'cheat' on this and use a modeller to make the curve track and then modify it
using a text-editor. I had origonally wanted to stay away from things that
would take away from the detail because I may be rendering this in a very
large resolution (to put on large paper for an art project). That's why I was
using CSG :)

Thanks for the help, though, as I said, I'll look for those Macros when
Twysted.net gets back on (and tutorials on that note, heh :)

Tim Soderstrom

Ken wrote:

> Tim Soderstrom wrote:
> >
> > One day while looking for something realistic to render, I thought of
> > making a modell train scene. I ended up wanting to create a series of
> > include files that could be used to make both model trains and real
> > trains (with some modification). So I made an include file for the
> > tracks. The problem is that I can make the straight peices, but the real
> > model curve peices are hard to modell using CSG, and I was hoping
> > someone could help me find a better way.
> >
> > I made the peices by declaring dimensions for the metal peices, etc. For
> > the curve, I used CSG differences to make
> > the wires from cylinders. I'm including the code with this, so someone
> > can get an idea.
> >
> > If there is any person that has made a model train include file, I would
> > like to see if (and refine my own file), so if you could direct me to a
> > source, that would work too.
> >
> > Thanks a bunch,
> >
> > Tim Soderstrom
>
>   I am not aware of any model train include files available but I may
> have a suggestion that will bail you  out of your curent delimma. As
> recently as one month ago there were 2 different extrusion macros
> posted to the povray.binaries.utilities group.
>   The macros takes a defined shape, in this case a cross section of
> track, along with a set of points describing a path to take, in this
> case the rail bed, and the macro will then extrude your shape along
> the path from the start to the end point. I can think of no easier
> way to do this  except it inside of a modelling program. One thing
> you should know is that the more points on a curve that you can
> supply the macro with the smoother the resulting curves and tracks
> will be. If you only feed it 4 points it will have some very sharp
> bends. If you feed it 30 - 40 or more points it will be very smooth
> as long as you don't stretch it out over many Pov units. A utility
> tht can generate spline curves would be a big aid in establishing
> the nessesary points to feed the macro. See the link below for a
> program that might aid you in this regard.
>
> Spline Editor:
> http://www.flashnet.it/users/fn027571/spil/index.html
>
> --
> Ken Tyler
>
> mailto://tylereng@pacbell.net

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Tim Soderstrom wrote:
> 
> I don't use Spline Editor - I use sPatch (both work well, but Spatch doesn't
> require control points - its downfall, however, is that it cannot do pure
> lathes - it converts them). I have considered using sPatch to make the curve,
> but the problem is that I may want to add some detail to the track. If I used
> sPatch, I would have to remodell the curuve. In any case, I will look for
> that macro on twysted.net (as soon as it works again) and see if that will
> help me. Really, the problem is not making the curve, it's getting the angle
> of the cut right and converting this value to a rotation of a box. I may
> 'cheat' on this and use a modeller to make the curve track and then modify it
> using a text-editor. I had origonally wanted to stay away from things that
> would take away from the detail because I may be rendering this in a very
> large resolution (to put on large paper for an art project). That's why I was
> using CSG :)
> 
> Thanks for the help, though, as I said, I'll look for those Macros when
> Twysted.net gets back on (and tutorials on that note, heh :)
> 
> Tim Soderstrom

  The macros I was referring to are located here on this server in the
povray.binaries.utilities group. I believe Giles Tran was one of the
people that posted a version and there was another one posted within a
day of two of his.


-- 
Ken Tyler

mailto://tylereng@pacbell.net

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