I would like to change the line width of a primitive created from a CircleGeometry. Is this possible? If it isn’t, is there a way to draw a Polyline using the positions from a CircleGeometry object?
No yet. You have to recreate the CircleGeometry and Primitive. It would be straightforward for you to make a wrapper like how RectanglePrimitive wraps RectangleGeometry. After we added all the low-level geometries to Cesium, we haven’t found the time yet to add wrappers other than Polygon and Rectangle.
How is the line width set in the first place?
There is neither a width property in CircleGeometry nor in CircleOutlineGeometry.
It is part of the appearance (conceptually at the graphic layer, width is not part of the geometry as strange as it sounds). See the lineWidth property in:
If you are running on Windows, I don’t think ANGLE supports wide lines yet, so you could use Cesium’s PolylineGeometry and related appearances, which workaround the ANGLE limitation. Use the positions created by the CircleGeometry to create the PolylineGeometry.
This post I made on Stack has a bunch of details on lack of WebGL line width on Windows: http://stackoverflow.com/a/25405483/3191039
Thank you for the information.
A note about 'lineWidth' in Geometry may be useful for non-opengl experts.