Is it a good idea to make stars by using CSG or should they be solid
blocks?
Brendan Ryan

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It kind of depends on what you are trying to do...
You could use a prism, CSG of a prism, a polygon, a mesh, etc. What are
you trying to accomplish?

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I'll try to make solid star prisms if I find out how to move a point
towards the origin.
Brendan Ryan

Andrea Ryan wrote:

> Is it a good idea to make stars by using CSG or should they be solid
> blocks?
> Brendan Ryan

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Andrea Ryan wrote:

> I'll try to make solid star prisms if I find out how to move a point
> towards the origin.
> Brendan Ryan

Multiply the coordinates of your point by the fraction of how much closer
you want the point to be to the origin.  For example, if you have a point
<x,y,z> and you want it to be only half as far away from the origin, it's
new coordinate will be .5*<x,y,z>

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I tried to divide every other vector by ptmove but it didn't work. This code
rotates and moves the odd numbered points and just rotates the even numbered
points. The code is in a while loop. Rotation_no and point_no both get added
to one at the end.
Brendan Ryan

#local determine = (point_no/2)-int(point_no/2);
#switch (determine)
#case (0.5)  //odd numbered point
#local vec =vrotate(<0,1,0>,<0,0,(angle_of_rotation*rotation_no)>/ptmove);
#break
#case (0) //even numbered point
#local vec=vrotate(<0,1,0>,<0,0,angle_of_rotation*rotation_no>);
#break
#end



Kevin Wampler wrote:

> Andrea Ryan wrote:
>
> > I'll try to make solid star prisms if I find out how to move a point
> > towards the origin.
> > Brendan Ryan
>
> Multiply the coordinates of your point by the fraction of how much closer
> you want the point to be to the origin.  For example, if you have a point
> <x,y,z> and you want it to be only half as far away from the origin, it's
> new coordinate will be .5*<x,y,z>

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Andrea Ryan wrote:

> I tried to divide every other vector by ptmove but it didn't work. This code
> rotates and moves the odd numbered points and just rotates the even numbered
> points. The code is in a while loop. Rotation_no and point_no both get added
> to one at the end.
> Brendan Ryan
>
> #local determine = (point_no/2)-int(point_no/2);
> #switch (determine)
> #case (0.5)  //odd numbered point
> #local vec =vrotate(<0,1,0>,<0,0,(angle_of_rotation*rotation_no)>/ptmove);
> #break
> #case (0) //even numbered point
> #local vec=vrotate(<0,1,0>,<0,0,angle_of_rotation*rotation_no>);
> #break
> #end

The problem here is that you divided by ptmove within the vrotate() statement.
Change the fourth line to this:

#local vec  =  vrotate(<0,1,0>,<0,0,angle_of_rotation*rotation_no>)/ptmove;

and it should work.

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Kevin Wampler wrote:
> The problem here is that you divided by ptmove within the vrotate() statement.
> Change the fourth line to this:
> 
> #local vec  =  vrotate(<0,1,0>,<0,0,angle_of_rotation*rotation_no>)/ptmove;
> 
> and it should work.

	Or faster:
vrotate(<0, 1/ptmove, 0>, <0,0,angle_of_rotation*rotation_no>);

		Jerome

-- 
*******************************

* they'll tell you what can't * mailto:ber### [at] inamecom
* be done and why...          * http://www.enst.fr/~jberger
* Then do it.                 *
*******************************

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Thanks! A five pointed star was rendered! I'll refine the code because the star is
really a decagon. The number of sides a star has is twice the number of points it
has. I'll divide the vector by the distance between the vertex of the decagon and
the midpoint of a pentagon inside the decagon to turn the decagon into a pentagon
with controllable midpoints.
Brendan Ryan

P.S. I call the distance "r" and it is equal to
(tan(180-(90+(180*((2*points)-2))/(2*points)/2)))*(cos(((180*(points-2))/points)/2))

where points is the number of points (the kind that look like arms, not the
vectors) that the star has.
I'll also be posting pictures of stars in the povray.binaries.images group.



Kevin Wampler wrote:

> Andrea Ryan wrote:
>
> > I tried to divide every other vector by ptmove but it didn't work. This code
> > rotates and moves the odd numbered points and just rotates the even numbered
> > points. The code is in a while loop. Rotation_no and point_no both get added
> > to one at the end.
> > Brendan Ryan
> >
> > #local determine = (point_no/2)-int(point_no/2);
> > #switch (determine)
> > #case (0.5)  //odd numbered point
> > #local vec =vrotate(<0,1,0>,<0,0,(angle_of_rotation*rotation_no)>/ptmove);
> > #break
> > #case (0) //even numbered point
> > #local vec=vrotate(<0,1,0>,<0,0,angle_of_rotation*rotation_no>);
> > #break
> > #end
>
> The problem here is that you divided by ptmove within the vrotate() statement.
> Change the fourth line to this:
>
> #local vec  =  vrotate(<0,1,0>,<0,0,angle_of_rotation*rotation_no>)/ptmove;
>
> and it should work.

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I have two pov files with the same contents and they both include the
include file that has the star macro. I can render a image with one of
the files but with the other file, I can't render a image. Both files
have the line
starbl (0,0,0,1,1,1,0,1,5,4)
"starbl" is the macro's name but it says that 'starbl' is an undeclared
identifier.
Thanks.
Brendan Ryan

Andrea Ryan wrote:

> Is it a good idea to make stars by using CSG or should they be solid
> blocks?
> Brendan Ryan

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Is it saved in a different directory? and is your macro file in the include
file and is the include file in your include path?

Andrea Ryan <ary### [at] global2000net> wrote in message
news:3802395C.D6E626C4@global2000.net...
> I have two pov files with the same contents and they both include the
> include file that has the star macro. I can render a image with one of
> the files but with the other file, I can't render a image. Both files
> have the line
> starbl (0,0,0,1,1,1,0,1,5,4)
> "starbl" is the macro's name but it says that 'starbl' is an undeclared
> identifier.
> Thanks.
> Brendan Ryan
>
> Andrea Ryan wrote:
>
> > Is it a good idea to make stars by using CSG or should they be solid
> > blocks?
> > Brendan Ryan
>

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