Now that sphere_sweeps are possible on the Mac, I want to try learning
them but the documentation is very thin.

Is there any way to sphere_sweep a regular multi-segment bezier_spline?

Look at "Celtic Cross" in image.binaries for an example of what I'm
trying to do and the problems I'm having with my current technique which
uses Chris Colefax's Spline macro. I'm hoping that sphere_sweep can cure
my ills.

Here's a sample of the spline data:

#declare spline_segments = 4;

#declare point0 = < -0.167, 0.3125, 0>;
#declare point1 = <2.5, 4.3125, 0>;
#declare point2 = <3.25, 4.167, 0>;
#declare point3 = < 0.0, 0.0, -0.25>;
#include "SplineR.inc"

#declare point0 = < 0.0, 0.0, -0.25>;
#declare point1 = <3.25, 4.167, 0>;
#declare point2 = <4.167, 4.167, 0>;
#declare point3 = < 0.167, -0.1042, 0.0>;
#include "SplineR.inc"

#declare point0 = < -0.1458, 0.167, 0>;
#declare point1 = <4.167, 4.167, 0>;
#declare point2 = <4.167, 3.25, 0>;
#declare point3 = < 0.0, 0.0, 0.0>;
#include "SplineR.inc"

#declare point0 = < 0.0, 0.0, 0>;
#declare point1 = <4.167, 3.25, 0>;
#declare point2 = <4.3125, 2.5, 0>;
#declare point3 = < 0.3125, -0.167, 0.0>;
#include "SplineR.inc"



steve

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Steve <ste### [at] puzzlecraftcom> wrote:

> Now that sphere_sweeps are possible on the Mac, I want to try learning
> them but the documentation is very thin.
> 
> Is there any way to sphere_sweep a regular multi-segment bezier_spline?
> 
> Look at "Celtic Cross" in image.binaries for an example of what I'm
> trying to do and the problems I'm having with my current technique which
> uses Chris Colefax's Spline macro. I'm hoping that sphere_sweep can cure
> my ills.
> 

As far as I know, the spheresweep primitive only supports linear, catmul
rom and b-splines.; no bezier_splines yet.

An object that looks like a spheresweep can be made of spheres,
connected by cones. When using enough spheres, it looks as smooth as a
spheresweep and renders much faster, but needs more memory (depending on
the number of spheres and cones). Another advantage of this object is
the possibility to create a color gradient along your 'sweep'. With
POV-RayUnofficial you can create such objects with the MultiCopy
template: choose from the 'Splines' panel the object 'Connected
spheres'.
The spline types supported here are the splines used for prism and
lathe: i.e. linear, quadratic, cubic and bezier, but only 2D.

smellenbergh

-- 
e-mail:sme### [at] skynetbe

http://users.skynet.be/smellenbergh

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I use Pov-Ray Unofficial almost all the time. It's a very well done version.

I have run into memory problems with my current sphere_sweep project, so I am
now developing techniques for minimizing memory requirements. My project is
very involved, using thousands of splines.

The bezier_spline really should be added to the sphere_sweep function in POV.
It's extremely useful having a high octane spline design tool such as
Illustrator or Freehand. While the Catmull-Rom can do the same job, it just
doesn't work with regular bezier artwork without extensive conversion.

I will certainly check out the Connected Sphere Multi-Copy feature!

steve



smellenbergh wrote:

> Steve <ste### [at] puzzlecraftcom> wrote:
>
> > Now that sphere_sweeps are possible on the Mac, I want to try learning
> > them but the documentation is very thin.
> >
> > Is there any way to sphere_sweep a regular multi-segment bezier_spline?
> >
> > Look at "Celtic Cross" in image.binaries for an example of what I'm
> > trying to do and the problems I'm having with my current technique which
> > uses Chris Colefax's Spline macro. I'm hoping that sphere_sweep can cure
> > my ills.
> >
>
> As far as I know, the spheresweep primitive only supports linear, catmul
> rom and b-splines.; no bezier_splines yet.
>
> An object that looks like a spheresweep can be made of spheres,
> connected by cones. When using enough spheres, it looks as smooth as a
> spheresweep and renders much faster, but needs more memory (depending on
> the number of spheres and cones). Another advantage of this object is
> the possibility to create a color gradient along your 'sweep'. With
> POV-RayUnofficial you can create such objects with the MultiCopy
> template: choose from the 'Splines' panel the object 'Connected
> spheres'.
> The spline types supported here are the splines used for prism and
> lathe: i.e. linear, quadratic, cubic and bezier, but only 2D.
>
> smellenbergh
>
> --
> e-mail:sme### [at] skynetbe
>
> http://users.skynet.be/smellenbergh

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Steve <ste### [at] puzzlecraftcom> wrote:

> Now that sphere_sweeps are possible on the Mac, I want to try learning
> them but the documentation is very thin.
> 

I just read the tread about the celtic cross in the
povray.binaries.images (didn't read much there because it takes to much
time to download!).
I want to point out that the sphere_sweep object is not supported by the
Pov-team. This object is a patch for Pov-Ray and therefore only
implemented in custom compiles.
The authour of the sphere_sweep is jochen lippert
<dar### [at] alfzfnuni-bremende>. You could ask him if he plans supporting
the bezier_spline in his patch.
For now, there is no bezier_spline support for the sphere_sweeps.

In the Pov-RayUnofficial you could draw a multisegmented
2D-bezier_spline in the MultiCopy panel (no import of points yet - has
still to be done manually). The assigned number of points will be placed
on each segment of the bezier_spline. These points are written to an
array that will be used by the sphere_sweep. But then you must choose
between the splines of the sphere_sweep to render it.
This means that MultiCopy can only be used to place inbetween points
'on' a bezier_spline. When setting enough inbetween points and rendering
with a linear_spline is the closest you will come to a bezier_spline
with the sphere_sweep at this time. But I doubt if it is a suitable way
for large amounts of splines.

smellenbergh 
--- 
e-mail:sme### [at] skynetbe

http://users.skynet.be/smellenbergh

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smellenbergh <sme### [at] skynetbe> wrote:

Hello, (Forgot you name, was it Ivo?)

> The authour of the sphere_sweep is jochen lippert
> <dar### [at] alfzfnuni-bremende>. You could ask him if he plans supporting
> the bezier_spline in his patch.

just wanted to point out this address is no longer valid, since long
ago. My currently preferred mail address is jli### [at] maccom.

I'm not sure if I will put much work in the Sphere Sweep primitive
anymore, though. It's all just too long ago. :)

Greetings and thanks for maintaining my code until it made it into the
official version (blush),

Jochen Lippert

-- 
No smilies were harmed in the making of this message ;)

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