Equation based surface with hfss

Hi! I ve tried to write an equation with one parameter. This doesnt make problems. The trouble appears when i try to use an equation based surface, because the result that hfss returns is:


[error] Body could not be created for part because of invalid parameters to CreateEquationSurface operation.

And i dont find the mistake.
I show: axis-->x= R0*cos(_u);
y= R0*sin(_u);
z= R0/tan(_v), where the parameters _u and _v are defined as:

R0 is a created variable.

Range_u belongs a right range;
Range_v belongs a right range;

Where is the mistake? what is wrong with the code?

Thank you.

Your 'z' formula does a division.

Does tan(_v) equal zero at any time? That would mean dividing by zero (which will generate an error).

You were right. but now, is not possible to create with this value for z a curve as a spiral. D you know how i must change this? If not, ill go on trying, but thanks so much. I didn't think that the result started at infinite, so the program me wasn't able to create something.

In some cases it may be necessary to add a tiny constant, to ensure the divisor will never be zero...

Or in other cases, you must skip plotting a point if some variable is too great, or if it is the wrong polarity, etc.