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Le 03/01/2012 20:55, Marina nous fit lire :
> I am trying to create the symbol to show circular polarization for a physics
> diagram so I need an arrow in the shape of a circle. However, the only way I can
> currently do it is to just make a circle and add a cone in one section... what I
> want is a slight gap between the head and tail of the arrow so it's not all just
> one continuous object. I haven't figured out how to use the features of POV-Ray
> that let you 'take away' from objects. Could anyone show me what the easiest way
> to go about this would be? At least point me in the right direction? I'd really
> appreciate it.
> Thanks! :)
>
>
Hello,
try to thing in 3D... your circle can be a torus.
CSG is what you need.
something along:
union
{
cone { 3*z,1,3*z+3*x,0 }
difference {
torus { 3,0.2 }
box { <0,-1,0>,<4,1,4> }
}
// apply texture as needed
}
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"Marina" <mbr### [at] huskers unledu> wrote:
> I am trying to create the symbol to show circular polarization for a physics
> diagram so I need an arrow in the shape of a circle. However, the only way I can
> currently do it is to just make a circle and add a cone in one section... what I
> want is a slight gap between the head and tail of the arrow so it's not all just
> one continuous object. I haven't figured out how to use the features of POV-Ray
> that let you 'take away' from objects. Could anyone show me what the easiest way
> to go about this would be? At least point me in the right direction? I'd really
> appreciate it.
> Thanks! :)
"Marina" <mbr### [at] huskersunledu> wrote:
> I am trying to create the symbol to show circular polarization for a physics
> diagram so I need an arrow in the shape of a circle. However, the only way I can
> currently do it is to just make a circle and add a cone in one section... what I
> want is a slight gap between the head and tail of the arrow so it's not all just
> one continuous object. I haven't figured out how to use the features of POV-Ray
> that let you 'take away' from objects. Could anyone show me what the easiest way
> to go about this would be? At least point me in the right direction? I'd really
> appreciate it.
> Thanks! :)
I think you just need to read up on the difference statement. Make your cone.
Make your torus. Make another object - a box or something to cut away the shape
you want to remove from the torus. Then combine the code for the box (or
whatever) and the torus into a difference statement:
http://www.povray.org/documentation/view/3.6.1/306/
This is from Pov-Ray for Windows's "Insert" menu:
// CSG difference, subtract intersections of shapes 2...N from Shape1
difference {
Shape1 {...} // Start with this shape
Shape2 {...} // This will be "cut out" of Shape1
ShapeN {...} // This will be "cut out" of Shape1
}
On the other hand, does it have to be a cone and a torus? You might also look
into prisms. Maybe make a closed linear 2D spline, and use it as the basis of
your prism.... to extrude it to 3D. Then you could have a nicely shaped tail
on it. (Using a linear spline, as opposed to some other type of spline would
make it easy to create sharp corners and angles.)
Charles
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