Determining angle from project north to true north

[Anonymous]

I have a text file of several surveyed ponts throughout my model.  I can select one of these points in my model and specify the coordinates of East/West, North/South, and elevation from this file, but how do I determine the angle from project north to true north from these surveyed points?

Thank you,

Nick

[constantin.stroescu]

• The survey points come with a True North orientation and they represent absolute values (conected to a world system)
• The Project North is an easy way to rotate the building so as its grids to be horizontal and vertical in order to allow a quick design process  - it works with relative values...

People that worked in Autocad understand it better : WCS versus UCS

In practice I use two methods:

1. when I have the project in an advanced phase of work and I want then to insert a Toposurface.

•  in Site Plane view, True North, insert Toposurface. The building will appear as in Project North (horizontal-vertical orientation).
• Select the Project Base Point (use filter in order to separate it from the Survey  Point Internal), unclip it and move it at a grid intersection (or a corner of the building). Draw then,  a Reference Plane through the grid intersection at an angle the building is orientated on site.
• Measure the angle with horizontal (angular dimension) .Click on Project Base Point and at Align to True North put the measured angle value.The whole will rotate .
• Now , select only the Toposurface and Rotate back with the measured angle ...

2. I begin with the Toposurface- no project yet...

• make the Toposuface
• draw in Site Level  (True North) a Model Line with the desired orientation of the building 
• in Level 1 (Project North) Manage >Rotate Project North >Align Selected Line ...the Model Line will snap to horizontal or vertical ...
• reasign the Elevation Views