Rules and Recommendations

This section lists the rules and recommendations to remember when creating catalog slots, endcuts and small assemblies.


  • Always explicitly define points and never use implicit points, for example those at the ends of lines.
  • Wherever possible, make selections in the specification tree.

Oriented Planes and Lines

  • Never invert the orientation of a plane without first checking whether or not the plane has children.
    In general, plane orientation must be known. This applies in particular to planes tangent to surfaces, planes offset or parallel to oriented planes, planes at an angle or normal to an oriented plane if the axis of rotation is a line of known direction.
  • Instantiate user feature SurfaceOrientation.CATPart to force plane orientation.
  • Always work with oriented lines, especially when used as axes of rotation. When creating lines via the Intersection command, instantiate user feature CurveOrientation.CATPart to force line orientation.

    User features are to be found in folder

Input Geometry

  • Do not use input geometry in knowledgeware rules or formula [F(x)]. If you need to do so, duplicate the surfaces using Offset (0 offset) or Extract commands and reference duplicated geometry in the rule or formula.

Taking Advantage of Shape Section Parameters

Using main geometric characteristics of shape sections rather than creating appropriate input geometry is recommended. This simplifies the definition of the catalog template and reduces data size of both the template definition and the features you place.

The following shape section parameters can be employed:

  • D: shape height
  • Bf: Flange width
  • Tf: flange thickness
  • Tw: web thickness
  • Radius1
  • Radius2
  • Slope

To include section parameters in your template definition, you must:

  • Create a knowledgeware parameter of the desired type and named as below

Shapen_(name of section parameter)
where n is a number identifying the numbre of parts to be selected by the user when instantiating the feature.

For example, Shape1_Bf

  • Create a knowledgeware formula [F(x)] that uses the parameter you defined.

Shape section parameters are then accessed directly when the user instantiates the feature.



  • Always sketch using the Sketch with Absolute Axis definition command:
  1. Set the sketch support type to Positioned and select a plane of known orientation as Reference.
  2. Set the origin type to Projection point and select a stable geometric point. Do not select a vertex.
  3. Set the orientation type to Parallel to line and select an oriented line.
  • Never set distance constraints in the Sketcher. To dimension distances, create offset planes in the Wireframe and Surface Design workbench, then set coincidence constraints based on these planes in the Sketcher.
  • Avoid creating circles constrained in tangency. Defining as much as possible using the Wireframe and Surface Design workbench is recommended.

Creating Slots, Endcuts and Small Assemblies

  • Always reference input geometry and never part document planes.
  • Aways select input surfaces and not surfaces of starter model plates and shapes.
  • Always ensure that the geometric entities are properly ordered, for example an intersection of two lines must be placed after the two lines. Use the Reorder command if necessary.
  • For slots and endcuts, always reference at least one entity of the plate or shape that will contain the feature.
  • For endcuts, ensure that Split cutting planes are oriented with respect to geometric elements.
  • For endcuts, ensure that the first Part Design feature (pocket, split, etc.) describing the endcut is the active feature. Select this component first when creating the template.