# Singular

#### D.9.4.2 plotRot

Procedure from library `surfex.lib` (see surfex_lib).

Usage:
plotRot(poly p, list #)
Similar to plotRotated, but guesses automatically which coordinates should be used. The optional int parameter can be used to set plotting quality.

It opens the external program surfex for drawing the surface given by p, seen as a surface in the real affine space with coordinates coords.

Assume:
The basering is of characteristic zero and without parameters.

Example:
 ```LIB "surfex.lib"; "Example:"; // More variables in the basering, but only 3 variables in the polynomial: ring r1 = 0, (w,x,y,z), dp; poly cayley_cubic = x^3+y^3+z^3+1^3-1/4*(x+y+z+1)^3; plotRot(cayley_cubic); // Three variables in the basering, but fewer variables in the polynomial: ring r2 = 0, (x,y,z), dp; plotRot(x^2+y^2-1); plotRot(y^2+z^2-1); // A cubic surface with a solitary point: // Use the additional parameter 3 to ask singular // to compute the singular locus before calling surfex. ring r3 = 0, (x,y,z), dp; poly kn_10 = x^3-3*x*y^2+z^3+3*x^2+3*y^2+z^2; plotRot(kn_10, 3); // The swallowtail: // a surface with a real solitary curve sticking out of the surface. // Use the additional parameter 3 to ask singular // to compute the singular locus before calling surfex. poly swallowtail = -4*y^2*z^3-16*x*z^4+27*y^4+144*x*y^2*z+128*x^2*z^2-256*x^3; ```