Adaptive Filtering

 

Filtering a cloud of points makes its manipulation easier. This task shows how to hide points on planar elements.
This filtering hides more points from the planar areas than from other areas.
That way, you can highlight bent areas.

See the Protect command to protect characteristic lines.
  • The points are hidden, not removed, unless you use the Physical removal option.
  • Within a filtering action, Undo cancels the last filter action performed.
  • Leaving the action with Close restores the cloud as it was before starting the filtering action.
  • The Adaptative value is displayed in the current unit
    (You can type the value in another unit, but it will be recomputed and displayed in the current unit).
  • It is not possible to filter a meshed cloud of points or a mesh.
  • When you filter scans or grids, you actually filter points: filtered points are hidden,
    and new scans or grids are created.
  • Points that have been physically removed can not be retrieved.
Open the Adaptative1.CATPart model the from the samples directory.

 

  1. Click Filter in the Cloud Edition toolbar and select the cloud of points. 

  2. The Filter dialog box appears.

  3. Select Adaptive. The value to type represents the local chordal deviation.

  4. Each time you click Apply, the computation is restarted on the whole cloud of points.
    The display of the cloud of points and the statistics are updated. 

      Step: 0
    Points to be filtered: 114250
    Remaining points: 114250 (100.00%)
      Step: 1
    Adaptative
    Chord: 0.02
    Remaining points: 7529 (6.59%)
    You can note that the free boundaries have not been respected.
    This may lead to inaccurate outputs in downstream operations such as meshings.
    To avoid this problem, select the Max. Distance  check box and leave it to 3mm.
    This will ensure that a maximum distance of 3mm is kept between the remaining points,
    thus preserving the shape of the part.
      Step: 3
    Adaptative with max. distance
    Chord: 0.02 Max. Distance: 3
    Remaining points: 7940 (6.95%)

  1. Select the Physical removal check box to delete the filtered points, thus optimizing the memory requirements.

  2. Click Reset to retrieve all the filtered points, i.e. points hidden in the present filtering action
    or in previous filtering actions, provided you did not select the Physical removal check box.

  3. Once you are satisfied with the result, click OK to confirm and exit the action.