This can be done but requires a little bit of work.
In 15b Antenna Toolbox (ver 1.1), there is a method called exportMesh which will give you the points and triangles used to solve the structure. [p, t] = exportMesh(antennaObj);
You can pass the p and t matrix to triangulation class in MATLAB
TR = triangulation(t(:,1:3), p);
The triangulation class has a method called freeBoundary which will give you the border edges of the spiral.
FF = freeBoundary(TR);
The border edges along with the point set p, will give you the outer boundary of the spiral for art work.
I hope this helps.
