CloudCompare forum

Hey!
What is the difference between "Compute cloud/mesh distance" and "Compute cloud/primitive distance"?
I'm comparing a point cloud to plane fit into this cloud using both tools. They return different Mean distances but the same Standard deviation.
I can't find anything about "Compute cloud/primitive distance" on wiki.

Results from random cloud sample:

cloud / primitive
[19:26:55] [Compute Primitive Distances] [Primitive: Dip: 006 deg. - Dip direction: 260 deg.] [Cloud: Job 001- Setup 001 - Cloud.las.section] [C2Prim signed distances] Mean distance = -5.77097e-07 / std deviation = 7.18714

cloud / mesh distance
[19:27:14] [ComputeDistances] Mean distance = -3.29643e-07 / std deviation = 7.18714

The Cloud to Primitive distance tool computes the distances to the real 'theoretical' primitive (it uses the equation).

While the Cloud to Mesh distance tool computes the distances to the mesh representation of the primitive (= a set of triangles). For curved primitives, you would have to increase the display resolution of the primitive object a lot to get an accurate enough representation that would give approaching values. And for a plane, you will always hit the numerical representation limit (which is typically around 1.e-7) as you are bound to have 2 triangles to represent the plane.