Parametric Wine Glass and Bowls
by pmoews, published
The rotate_extrude command in openSCAD has fascinating posibilities. It can replace the potters wheel and the woodworkers lathe. All one has to do is draw a 2 dimensional profile of a clay pot or wooden bowl, convert it to a polygon, invoke rotate_extrude and a pot or bowl is produced.
Here is a parametric program that uses the rotate_extrude command to make wine glasses, glasses, and bowls. Examples outputs are given below:
The parameters that produced the above outputs are appended as comments to the openSCAD program make_wine_glass.scad.
The openSCAD program was designed to produce a stemmed wine glass.
Seven parameters need to be set. They are:
the diameter and thickness of the base of a wine glass,
the diameter and length of the wine glass stem
the vertical height of the cup and the angle it makes with the horizon
and finally the thickness of the wall of the cup.
The same program can be used to make a bowl. To do so the stem length is made very small and the stem is given the same diameter as the base.
A glass is simply a bowl where the angle made with the horizon is nearly 90 degrees.
The cat food bowl is one where the angle is 95 degrees; it curves inward to reduce spillage.
A bowl with an angle greater than 90 degrees can cross over itself and invert, There is little contact between the inverted bowl and the original bowl so the join is very weak. Very large angles give unexpected results.