Creating mesh on a surface with two variables

Question

I have an equation like this: $\cos(z)+\sin(x)+\sin(y)=1$ and I want to do something like:

Graph in blender a function of two variables,

I followed the proposed method in the same post. It was great and worked fine for many cases.

1) I cannot use arccosine(1-sin(x)-sin(y)). arccos and acos don't work either. What is the solution? Thanks in advance for your comments.

2) is there any possible way to determine a range for $z$ as well?

Answer 1

The Python function 'acos' has a parameter's domain between -1 and 1. If the parameter is out of this, you get a 'domain error'.

So for instance, you can set the following formula:

acos( (1-sin(x)-sin(y)) % (1 if (1-sin(x)-sin(y)) >0 else -1 ) )

or more simple (using 'fmod' which is C style modulo as Python's native modulo sign rely on the divisor sign)

acos( fmod( (1-sin(x)-sin(y)), 1 ) )

which is limiting the parameter's values.

Or alternatively to have a linear transition, limiting the parameter value like this:

acos( ((1-sin(x)-sin(y)) + 1) / 4 )

The result is the following:

or:

For your information, the math functions available in the addon:

safe_list = ['math', 'acos', 'asin', 'atan', 'atan2', 'ceil', 'cos', 'cosh',
    'degrees', 'e', 'exp', 'fabs', 'floor', 'fmod', 'frexp', 'hypot',
    'ldexp', 'log', 'log10', 'modf', 'pi', 'pow', 'radians',
    'sin', 'sinh', 'sqrt', 'tan', 'tanh']

And these links to stack overflow:

• About acos.
• About modulo.