Shap3d39.dat, 39th 'shape' file for CPO3D
Square hole in a round disc, by users equation.
For information on the option for users equations, see users equations.
See also shap3d37 and shap3d40.
The equations, say g1(x,y,z), for the inner square edge are
x = s, y = s*tan(phi), z = 0, where phi = 0 to pi/4.
The equations, say g2(x,y,z), for the outer circular edge are
x = r*cos(phi), y = r*sin(phi), z = 0.
In the usual fashion we can combine these by using the general equation
g(x,y,z) = (1 - f)*g1 + f*g2,
where f goes from 0 to 1.
This reproduces g1 when f = 0, and g2 when f = 1.
To concentrate the segments near the inner edge, we can use f^2 instead of f.
Here s = 0.25, r = 1, and 3 symmetry planes are used.
The equations, as they appear in the data file, are:
f 0 1 name of variable number 1 and its limits
phi 0 0.785 name of variable number 2 and its limits
r 1 name of parameter number 1 and its fixed value
s 0.25 name of parameter number 2 and its fixed value
0 name of parameter number 3 and its fixed value
0 name of parameter number 4 and its fixed value
1 1 numbers of 2 applied voltages (can be same)
10 10 numbers of subdivisions of variables 1 and 2
(The program has corrected the less accurate value that was entered for pi/4.)