There used to be a program called torpatch.exe that could create a
smooth curve of toruses through an arbitrary list of points.  If you
know where to find it, you can still find a copy.  It was very nice
for creating arbitrary bent tubular objects like garden hoses, wires,
lamp cords, spirally-twisty glass tubes like those in a chemistry lab
(Ahem, IRTC participants) and so on.

Now, with macros and arrays in POV 3.1, you can do everything torpatch
could do and more without leaving your favorite POV editor.  Just
include my nifty new include file, #declare an array of points, and
invoke the cool new TorusSpline macro to create an object.

This amazing new include file is available from
http://www2.fwi.com/~parkerr/traces.html

What documentation there is (you don't really need much) is included
in the .inc file.

If you do anything cool with it, please drop me a line.  If you create
a picture that looks better than the ugly demo image I have now, I'll
even put it on the page (with proper credit, of course.)

If you add lots of neato options to it, let me know about that, too.
I'd be happy to incorporate them if they seem useful.

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Ronald L. Parker wrote:
> 
> Now, with macros and arrays in POV 3.1, you can do everything torpatch
> could do and more without leaving your favorite POV editor.

This is incredibly useful.  torpatch suffers from being 
an external application : it can't be incoporated
into parameterized models and can't be used for animations.

I should be able to use it in my bicycle model for the
brake and derailler cables... I was going to use the spherical
extrusions in POVTM (in effect, a superset of what your macro
provides), but POVTM crashes on my rear derailler :).
Now I just need to upgrade my code to POV-pi compliance....

Dan

-- 
http://www.flash.net/~djconnel/

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On Mon, 20 Jul 1998 17:43:10 GMT, Ronald L. Parker 
<par### [at] mailfwicom> wrote:
>Now, with macros and arrays in POV 3.1, you can do everything torpatch
>could do and more without leaving your favorite POV editor.  Just
>include my nifty new include file, #declare an array of points, and
>invoke the cool new TorusSpline macro to create an object.
>
>This amazing new include file is available from
>http://www2.fwi.com/~parkerr/traces.html

There's a new version of this include file at the same address.  The previous
version would sometimes mess up the clipping planes while offsetting them to
avoid the coincident surfaces problem.  Also, the merge has been replaced by
a union because it wasn't working anyway and union is faster.  This means
that you can't use the splines for glass tubes, but you couldn't anyway due
to an apparent bug in POV-Ray.

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On Mon, 20 Jul 1998 17:43:10 GMT, par### [at] mailfwicom (Ronald L. Parker)
wrote:
> This amazing new include file is available from
> http://www2.fwi.com/~parkerr/traces.html

I know, I know, that's veeery old post but if somebody will run it with 3.5
with first segment along StartVect then it refuses to parse becouse of "can't
normalize zero length vector" message. It helps when content of #else block of
first #if is replaced with:

  #local Axis=vcross((B-A),V);
  #if(vlength(Axis)!=0)
    #local Axis=vnormalize(vcross((B-A),V));
    #local Dir=vnormalize(vcross(V, Axis ));
    #local Cos=vdot(vnormalize(B-A), Dir);
    #local Radius=abs(.5*vlength(B-A)/Cos);
    #local Center=A+Radius*Dir;
  #else
    #local Cos=0;
  #end 

btw1: page is not accessible
btw2: I wonder if it could be implemented as type of spline{} in 3.5

ABX

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Hi all,

if I may add my 2 cents:

btw3: Though its doubtlessly more correct to complain about impossibility to
normalize vector of length zero instead of returning <0,0,0> like old
versions did, this behaviour should perhaps be mentioned in "changes that
may break old scenes". TORSPLINE is probably not the only macro out there
that relies on "vnormalize( <0,0,0> ) = <0,0,0>" - my polyhedron-WIP did so,
too :-(

btw4: how about shay's cheap_sweep.inc, published a while ago in the
appropriate newsgroup ? that could be a replacement for many applications of
torspline, though it doesn't give the same geometry - BUT it might as well
suffer from changed behaviour. Didn't test that yet, but there's lots of
vnormalize-calls in it ...

Karl
--
The two most common things in the universe are hydrogen and stupidity.
(H.Ellison)

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