Documentation / loaders / convertStrandUpAxis
Function: convertStrandUpAxis()
convertStrandUpAxis(
positions,upAxis):Float32Array
Defined in: libs/loaders/src/curves/upaxis.ts:40
Rotates control points from upAxis into the engine's Y-up frame, in place.
Parameters
positions
Float32Array
Control point positions, 3 floats per point, modified in place.
upAxis
Up axis the positions are currently expressed in.
Returns
Float32Array
The same array, for convenience.
Remarks
Z-up becomes Y-up by a -90 degree rotation about X, (x, y, z) to (x, z, -y) - the same convention glTF uses for Z-up authoring tools. It is a rotation rather than an axis swap, so the determinant stays positive and triangle winding is unaffected.