Aligning Clouds with Constraints

You can align a cloud of points with a reference by defining constraints based on canonic shapes and applying a priority order on those constraints.

  • Align with Constraints requires you have access to Digitized Shape Preparation.
  • Constraints are defined by pairs of elements.
  • Canonic shapes can be:
    • Points
    • Lines
    • Planes
    • Spheres
    • Cylinders
    • Circles
    • Their inverted elements.

See Also
Solving Constraints Errors While Aligning Clouds
Aligning a Cloud Using the Previous Transformation
  1. Select a geometrical set as Define In Work Object to store the output.
  2. From the Control section of the action bar, click Align with Constraints .
  3. Select the Cloud to Align (this is the cloud to reposition).
  4. Use Hide/Show as required.
  5. Click Add to define a first constraint by pairing two elements, one on the cloud to align, the second on the reference.
    1. Select a canonic shape on the cloud to align, then one on the reference.

      • Define at least one constraint.
      • Always pick a constraint element on the cloud to align first, then one constraint element on the reference.

  6. Repeat step a. as required.

    The colors of the picked constraint elements change:

    • A color is associated to each couple of constraint elements that define a constraint.
    • The constraint element selected on the cloud to align is displayed in a solid color.
    • The constraint element selected on the reference is displayed in a transparent color.
    • Another color is associated to the next couple of constraint elements.

  7. Set the orientation of lines or axes selected on the cloud to align.
    • Automatic: The orientation of the constraint element is automatically optimized and not displayed (time-consuming).
    • Manual: The orientation of the constraint element is represented by a red arrow. Click the arrow to invert the orientation.
    • Use Invert Orientation to invert the orientation of constraint elements on the reference

    The constraints created are listed in the dialog box, with their priority order.

  8. Right-click a line of constraints and select a level of priority.

    • Strict
    • High
    • Above average
    • Average
    • Below average
    • Low

  9. Decide to keep the initial cloud or not.

    By default, the Keep Initial check box is selected:

    • The initial cloud to align is kept as such.
    • A copy of this initial cloud to align is made and appears in the tree.
    • This copy is aligned with the references.

    1. Clear this check box if you do not want to create a copy of the initial cloud to align, for example because of its size. The initial cloud to align itself is aligned with the references.

      Note: To avoid inconsistencies, you cannot clear the Keep Initial check box in the following two cases:
      • When the geometry of the cloud to align is shared by other cloud elements, for example when the cloud to align shares points or vertices with another cloud without any parent/child relationship between them. Clearing the Keep Initial check box would move the other cloud together with the cloud to align, which you do not want to.
      • When the cloud to align is a feature, for example a Generative Shape Design transformation feature.

  10. Click Apply to start the alignment.
  11. Click More to display the Statistics.
    • Alignment # indicates the step of the computation: In the picture above, Alignment #1 indicates this is the first computation launched since we have opened the dialog box.
    • Each constraint is described by:
      • Its number Constraint #
      • The type of the constraint and the constraint element selected, e.g. type: line (CylinderAxis.2) / line (CylinderAxis.1)
      • The priority applied to this constraint (for example High)
      • The distance (dist.=) and the angle (angl.=) between the constraint element on the cloud to align and the constraint element on the reference.

  • If Keep Initial is selected, a new cloud, in fact the copy of the initial cloud to align, is created, and aligned with the references. The new cloud has the same graphic properties as the initial cloud to align.
  • If Keep Initial is not selected, the cloud to align is aligned with the references and no new cloud is created.
  • In both cases, an Axis Systems is created with an AxisRef.x (system axis computed on the cloud to align) and an AxisTrs.x (axis system created on the output cloud).
  • Those Axis Systems can be used with the Axis to Axis action on other elements to align.
  • Align with previous transformation is available.