Smoothing Meshes

This task shows you how to smooth a mesh.

The cloud of points you import in Digitized Shape Editor may be noisy, for various reasons,
mainly because of a poor digitalization accuracy on the edges of parts.
This noise is found again on the meshes computed from these clouds of points or imported
in STL format.

The consequences are:

  • very noisy scans produced with the Planar Sections or Segmentations actions or
  • the reconstruction of wavy curves or surfaces and/or of very high order. 

This can be partly avoided by smoothing the mesh.

  • This action cannot be used on meshes with non-manifold edges.
  • Since the volume of the part is reduced, some small facets may be inverted by the meshing.
    Therefore we recommend you alternate Mesh Smoothing and Flip Edges actions.
  • Use the Activate function to process only a portion of a cloud.
Open the SmoothMesh01.CATPart from the samples directory





  1. Click Mesh Smoothing  and select a mesh.

  2. The Mesh Smoothing dialog box is displayed.

  1. Select the type of smoothing:

  • Single effect if there is no sharp edge on the mesh to process.
    • Small radii will be erased.
    • The volume of the part will be reduced (contraction towards the center of gravity of the part).
  • Dual effect to reduce the distance between outliers and the surface,
    and reduce the erasing of small radii. 
    • The reduction of the volume of the part is smaller.
    • A large displacement of one vertex inwards may cause the neighboring vertices to move outwards. 
  1. Two other controls are available:

  • Coefficient: It balances the effect of the new theoretical position in comparison
    with the original position.
    It varies from 0 (the vertex is not moved) to 1 (the vertex is moved to the computed position). 
  • Max Deviation: Select this check box to control the maximum deviation allowed
    (the displacement will remain under the value set.)
    • The deviation is the distance between a vertex and its initial position
      (not between its current position and that of the previous iteration).
    • Therefore, if you want to control the maximum deviation, you have to check the
      Max Deviation
      option before the first Apply (it is no longer available after the first Apply).
    • For a better appreciation of the quality of the intermediate meshes, the meshes are
      displayed in Flat Shading within the action. 
    • In addition, for each step the maximum and the mean deviations
      (distances between a vertex and its initial position) are displayed in the dialog box.
  1. Click Apply: a new mesh is computed.
    This action is an iterative one: click Apply again to smooth the proposed mesh. 

  2. Click OK once you are satisfied.
    A Smoothing.x element is created in the specification tree,
    the original mesh is sent to the No Show. 



Original part, before entering the action, i.e. in Smooth Shading:

Original part as you enter the action, i.e. in Flat Shading:

Single effect, in Flat Shading

Single effect, in Smooth Shading (after exiting the action)

Dual effect, in Flat Shading

Dual effect, in Smooth Shading (after exiting the action)