Helicoid

<<Own`Mesh`

Parameters

R=2;
nr=15;
nt=30;

Surface Data

f[r_,t_]:={Sin[t] Sinh[r],-Cos[t] Sinh[r],t}

n[r_,t_]:={Cos[t] Sech[r],Sech[r] Sin[t],-Tanh[r]}

domain=RectangularDomain[NRange[-R,R,nr],NRange[0,2Pi,nt]];

mesh=MeshPlot3D[{f[r,t],n[r,t]},{r,t},domain];

Show[Mesh3DToGraphics3D[mesh]]