Surface Flatness

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This command allows you to inspect the flatness of a mesh or a point cloud. An inspection value will be associated to each point of the cloud or vertex according to the local flatness.

Requirements

Select the mesh(es) or the cloud(s) and launch the command. Or launch this command without selection, to analyze planar parts of a cloud or a mesh.

  1. Without selection:

    1. Give a seed point to extract a "planar" part that you want to analyze.

    2. Adjust the extraction Tolerance.

    3. Click Validate to confirm the selection.

  2. With Selection (or after step 1c):

    1. Define the Ruler dimension

    2. Define the Tolerance to be respected.

    3. Optionally, if a mesh has been selected, check Compute gridded inspection to compute a grid of inspected points in addition to the inspected mesh.

      1. Define the Horizontal axis of the grid (Z must be 0).

      2. Define a point to Pass through.

      3. Define the Horizontal step of the grid (ie along the Horizontal axis).

      4. Define the Vertical step.

      5. Optionally, after the preview, export the points directly to CAD:

        1. Set the texts height in model space.

        2. Export to DXF or Send To.

Notes

  • A default color map is proposed with 2 thresholds: green for points inside the tolerance, red for points above the tolerance (points are above the ruler) and blue for points below the tolerance (points are below the ruler).

  • The export will use the currently active coordinate system.

Tips & Tricks

  • You can use Measure Deviation in the quick measure toolbar to add labels to the analysis.

  • In case of a wall inspection, you have to create first (and activate) a User Coordinate System with a Z-axis perpendicular to the wall.

Technical information

The calculated inspection value is local. It means that the flatness calculated for each point only considers its neighbors within a maximum distance of half the ruler dimension.

  1. The algorithm moves a cylinder aligned to the Z axis all along a regular grid covering the object surface. The ruler radius corresponds to the cylinder radius.

  2. For each cylinder position, a best local plane is computed.

  3. Then it compares points inside the cylinder to the local plane so as to evaluate the flatness of the associated area according to a given tolerance.

Practise

See the Exercise: Complete analysis of a concrete floor in the beginners guide section.