Measurements

Use the Measure tool (M) to select two points on the same model. After THOTH computes the distance, complete the annotation details dialog and choose Create measurement. The scene tree then provides edit, visibility, and delete controls.

Distances are displayed to four decimal places. THOTH uses the scene's model units; deployments should ensure imported models use a consistent real-world scale if values are expected to represent metres.

Distance modes

Mode	Calculation	Requirements
Euclidean	Straight line between the two selected points.	The points must belong to the same model.
Geodesic	Approximate shortest path along connected mesh vertices using A*.	Both points must be on the same mesh and a connected vertex path must exist.
Exact Geodesic	Surface path computed by the native Kirsanov/Mitchell-Mount-Papadimitriou addon.	Both points must be on the same triangular, manifold mesh and the server addon must be installed.

The approximate mode snaps the endpoints to nearby vertices. Exact mode welds coincident vertices and removes invalid or duplicate triangles before sending a model-local mesh to the same-origin server. It rejects non-manifold edges. The server caches the mesh by ID for later exact queries, but the cache is in memory and may be empty after a restart.

THOTH reports an error instead of creating a measurement when the points span models or meshes, no path exists, the geometry is incompatible, or the exact-geodesic service is unavailable.

All canonical measurement endpoints are stored in model-local coordinates. The computed display path is runtime data; export stores the endpoints, distance, and distance type.