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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