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Paraboloid OpenSCAD Script

by Ablapo, published

Paraboloid OpenSCAD Script by Ablapo May 5, 2013

Description

Ever wanted a elliptic paraboloid solid for OpenScad? Here it is!

What is a parabolic reflector good for?
Solar cookers, parabolic microphones, satellite dishes, spotlights reflector
http://en.wikipedia.org/wiki/Parabolic_reflector

Parabolic reflectors focus parallel rays at a focus point (e.g. sun rays).
And it can make circular rays at the focus point go parallel in one direction (spotlight).

It seems to be "similar" to the nose cone design of aircraft and model rockets, too. http://en.wikipedia.org/wiki/Nose_cone_design

Usage :
paraboloid (y=50,f=10,rfa=0,fc=0,detail=44);

To create a paraboloid choose following parameters:

  • height (y); This defines the vertical height
  • focus length (f); This defines the distance of the focus point from the top
  • radius of focus area (rfa); You can have a focus circle (rfa>0) instead of a focus point (rfa=0)
  • center focus center (fc); Choose the center on top (fc=0) or center in focus point (fc=1)
  • fine structure (detail) ; defines the numbers of subdivisions - $fn

Recent Comments

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The second method is exactly what I did. Thanks!
This is the same method you use for cups or vases:

Try to set your slicing software to this settings:
perimeters = 2 or 3
bottom layers = 2 or 3
top layers = 0
Infill = 0%

Or you can use OpenScad and calculate something like this:

difference(){
paraboloid (y=50,f=10,rfa= 0,fc=1,detail=120);
translate([0,0,+2])
paraboloid (y=50,f=10,rfa= 0,fc=1,detail=120);
}
How can I make this shape hollow, like in the images you posted?

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Instructions

How to print the paraboloid example:
Print it with support structure for best results.
Slice it with 3 perimeters, no top, no bottom, no infill.

For some light experiments:
You can try to cover the inner surface with a reflecting material.
You can insert a stick into the small opening on top.

How can I make this shape hollow, like in the images you posted?
This is the same method you use for cups or vases:

Try to set your slicing software to this settings:
perimeters = 2 or 3
bottom layers = 2 or 3
top layers = 0
Infill = 0%

Or you can use OpenScad and calculate something like this:

difference(){
paraboloid (y=50,f=10,rfa= 0,fc=1,detail=120);
translate([0,0,+2])
paraboloid (y=50,f=10,rfa= 0,fc=1,detail=120);
}
The second method is exactly what I did. Thanks!
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