Hi,

I wanted to use some non-orthogonal curve linear coordinates. I have entered them into maple by:

with(VectorCalculus):
assume(r>0,theta<=0,theta<Pi,0<=phi,phi<2*Pi);
AddCoordinates( 'myCoords1'[r,theta,phi], [(L+r*cos(theta)+Delta(r))*cos(phi),(L+r*cos(theta)+Delta(r))*sin(phi),r*sin(theta)] );
 

However this gives the warning:

Warning, the unit Vectors in the new coordinate system are not orthogonal, only added to global coordinate systems