Unfortunately, the angleToTrueNorth
is Revit only, i.e., translating RVT directly with Model Derivative API, as far as I know.
model.getData().metadata[ custom values ].angleToTrueNorth
However, if your NWC/NWD model was exported from RVT using shared coordinates after last April, then we could calculate that from the nwModelToWorldTransform
transform in the manifest.
"derivatives": [
{
"name": "racbasicsampleproject.nwc",
"hasThumbnail": "true",
"status": "success",
"progress": "complete",
"properties": {
"Document Information": {
"Navisworks File Creator": "nwexportrevit",
"nwModelToWorldTransform": [
0.7986355100472902,
0.6018150231520518,
0,
-0.6018150231520518,
0.7986355100472902,
0,
0,
0,
1,
-65.03805139774867,
-61.70701987942478,
0
]
},
///...
Here is how we can calculate the angle to true north from the transform:
let model = viewer.getAllModels()[0];
let doc = model.getDocumentNode().getDocument();
let docRoot = doc.getRoot();
let docInfo = docRoot.children[0].data.properties[ Document Information ];
let angle = THREE.Math.radToDeg(Math.acos( docInfo.nwModelToWorldTransform[0] ))
let angelToTrueNorth = -1.0 * angle; //!<<< The angelToTrueNorth is clockwise, but the angle in math is counterclockwise
So, using the above nwModelToWorldTransform
transform for example, the calculated angelToTrueNorth will be:
let angle = THREE.Math.radToDeg(Math.acos( 0.7986355100472902 )); //<<< 37°
let angelToTrueNorth = -1.0 * 37; //!<<< -37° = 323°