Signed Distance: find the smallest gap between two meshes

Signed Distance finds the smallest distance between two meshes and shows where it is. If the meshes intersect, it shows the deepest overlap as a negative number. Use it to check the clearance between two parts of an assembly or how far one part goes into another.

You find the tool in Inspect › Signed Distance.

Measure the Gap Between Two Parts

1. In the Scene tree, select exactly two meshes: click the first one, then Ctrl+click (Cmd+click on macOS) the second. With any other selection the tool stays disabled.
2. Go to Inspect › Signed Distance. MeshInspector computes the result at once.
3. Read the result in the viewport: A marks the closest point on the first mesh (the one higher in the Scene tree), B the closest point on the second mesh, a line connects them, and the number next to it is the signed distance in scene units.
4. Move one of the parts, for example with the tools of the Transform tab: the result updates by itself. Click Find signed distance to compute it again at any time.

In this example the second part is a copy of the first, moved so that 1.5 mm stays between them. The tool finds the two closest points on the rounded edges and reports 1.500690.

Find How Deep Two Parts Intersect

When the meshes intersect, the number is negative and shows the largest depth of the overlap. For example, a copy moved 1 mm into the part gives about −1 (−0.998711 in the picture below).

To see the overlap, click Select internal part: MeshInspector selects the triangles of each mesh that lie inside the other mesh. Clear removes this selection from both meshes. You can continue with the selected area, for example check it or remove it with the tools of the Select tab.

The Benchmark section times the computation (Smart search time and Full search time). It is meant for performance tests; you don't need it to measure.

Which Distance Tool to Use

• Signed Distance: one number for two meshes, the smallest gap or the deepest overlap, with the place where it occurs.
• Surface Deviation: a color map of the distance from every point of one object to a reference object, for example a scan against its CAD model.
• Surface Distance: the distance along the surface of one mesh from a picked point.
• Measure Distance: the straight distance between points you pick.