How to get true north direction in XYZ?

[prasannamurumkar]

Requirement is to get angle between the roof element face orientation with true north.

Want to get true north direction in XYZ beacause i am having face normal direction in XYZ so i can use angle to Api to get angle.

Able to get projectPostion and other things.

ProjectPosition projectPosition = projectLocation.GetProjectPosition(XYZ.Zero);
double angleProject = projectPosition.Angle;

Also got east/west ,south/north.

 

but from that not sure how to get direction of true north in XYZ could anyone help?.

[jeremy_tammik · Accepted solution]

You can look at the DirectionCalculation SDK sample and its module FindSouthFacingWalls.cs.

It is discussed in various places by The Building Coder:

• Analyse Building Geometry
• South Facing Walls
• Transformations
• Project Location
• Highlight Elements
• Basel.js Meetup View and Data API Demo
• Parameters, Walls and Driving Revit via WCF Service
• FilterRule Use and Retrieving Exterior Walls
• Triangle Count, New Floor and Slab Creation

[prasannamurumkar]

Thank you for reply.

Now testing below code for getting true north  may be this will work.

Here assumption is our project north is always upward (new XYZ(0,1,0) and then taken translation and rotation.

From that if we want the true north tried to use below lines:

ProjectPosition projectPosition = projectLocation.GetProjectPosition(new XYZ(0,0,0));
Transform rotationTransform = Transform.CreateRotation(
new XYZ(0,0,1) , projectPosition.Angle);

XYZ translationVector = new XYZ(projectPosition.EastWest, projectPosition.NorthSouth, projectPosition.Elevation);
Transform translationTransform = Transform.CreateTranslation(translationVector);
Transform finalTransform = translationTransform.Multiply(rotationTransform);

XYZ pointTrueNorth= finalTransform.OfPoint(new XYZ(0, 1, 0));

Could anyone tell whether i am proceeded in right direction?.

[mhannonQ65N2]

For your last line, you should be using OfVector instead of OfPoint because the XYZ for true north is a vector, not a point.

[prasannamurumkar]

thanks.

[prasannamurumkar]

thank you.