Using Polyline for shapefiles

I just tested the use of Polyline to render polygons and lines (from a shapefile) into WWJ, to achieve to power of "follow terrain" property.
Unfortunately it is very slow, at least in my ancient laptop.

Another solution I test is the use of SurfacePolygon to render the shapefile polygon elements. It have a good performance but you lost precision transforming vectorial data into a bitmap.

Depending on your needs you can chose between the two options.