[quote user="Barry Lothian"]I've been almost successful using the suggested method but I seem to be fighting against MicroStation's method of calculating angles[/quote]
MicroStation is not attempting to be perverse: it follows the geometric algebra convention of measuring angles. In 2D, angles are measured counter clockwise (CCW) from the X-axis.
Angles and Matrices Example
I've written a VBA project that illustrates the value of matrices (VBA Matrix3d) when calculating angles...
Image may be NSFW.
Clik here to view.
Here's the VBA project: (Please visit the site to view this file)
