Before You Begin 

What is SmartPick?

SmartPick is an intuitive, easy-to-use tool designed to make all your Sketcher creation and edition tasks as simple as possible. SmartPick dynamically detects the following geometrical constraints:

  • support lines and circles
  • alignment
  • parallelism
  • perpendicularity
  • tangency
  • concentricity
  • horizontality and verticality
  • midpoint

What are Constraints?

There are times when simple sketches are adequate for your design process, but you will often need to work on more complex sketches requiring a rich set of geometrical or dimensional constraints. The Sketcher workbench provides constraint commands which will allow you to fully sketch your profiles.
When you apply constraint on curves, lines, circles and ellipses, the complete geometrical support is taken into account. 

As an example for this arc, the entire circle is taken into account when you apply constraints.
The location you click when selecting the elements to constrain is taken into account to create the constraints (it is used to position the constraints accurately). Therefore, when selecting the elements to constrain, it is important that you click where you want the constraint to be positioned. The software will then position the constraint according to the area where you clicked. 
This is especially true when creating constraints on certain types of curves (complex curves like splines, for example). In some cases, if you don't click in the right place when selecting the curve to constrain, the constraint and the geometry will be inconsistent. 

Geometrical Constraints

A geometrical constraint is a relationship that forces a limitation between one or more geometric elements. For example, a geometrical constraint might require that two lines be parallel. If you select three lines, or two lines and a point, these elements will automatically result parallel to each others, as illustrated in the table further down.

You can set a constraint on one element or between two or more elements.
  Number of Elements  

Corresponding Geometrical Constraints
  One Element Fix
Horizontal
Vertical

 
  Two Elements Coincidence
Concentricity
Tangency
Parallelism
Midpoint
Perpendicularity

 
  Three Elements Symmetry
Equidistant Point
  When creating your constraint, remember that a green constraint is a valid constraint by default. Conversely, a yellow constraint indicates that the definition is not valid. The software lets you customize the colors and more generally the style of the constraints you use. To have details about these capabilities, see Infrastructure User's guide.

When you position the cursor on constraint symbols, the software calls your attention on the elements involved in the constraint system. Here are two examples of what you may get.

Dimensional Constraints

A dimensional constraint is a constraint whose value determines geometric object measurement. For example, it might control the length of a line, or the distance between two points.

You will use Constraint to finalize your profile. The Constraint command allows you to set dimensional or geometrical constraints but you will mainly use it to set dimensional constraints.

You can combine dimensional constraints to constrain a feature or sketch.

You can set a dimensional constraint on one element or between two elements.
  Number of Elements

Corresponding Dimensional Constraints
  One Element Length
Radius/Diameter
Semimajor axis
Semiminor axis

 
  Two Elements Distance
Angle

 
  You can apply a diameter constraint between two lines provided one of these lines is an axis line.
 

What About Constraining While Sketching?

Provided you previously activated Constraint , sketching certain elements automatically generates constraints although you did not specify that you wanted these elements to be actually constrained.

What About Constraint Visualization?

The table below lists the symbols used to identify the different constraint types:

 

Symbol

Constraint Type
Perpendicular
Coincidence
Vertical
Horizontal
Fix/Unfix
Parallel
/  Radius/Diameter
 

Hiding or Showing Constraints

Three existing settings are available from the Visualization toolbar. They all let you adjust the visualization of constraints according to your needs. You can hide:

  • constraint diagnoses just by deselecting the Diagnosis icon
  • dimensional constraints just by deselecting the Dimensional Constraints  icon.
  • geometrical constraints just by deselecting the Geometrical Constraints  icon

To know more about these capabilities, refer to the Filter paragraph in Symbols.
 
The visualization mode of constraints is based on the 3D constraints visualization filter.

The constraints visualization filter settings applied while editing a sketch are specific to this sketch and prevail over the settings defined in the 3D constraints visualization filter (Tools> Options> Parameters and Measure>  Constraints and Dimensions> Filter).

These specific settings will be kept every time the sketch is edited.

What About Constraint Colors?
 

 

 As soon as you detect a constraint problem, try to solve this problem. Otherwise, if you let the model be overloaded with diagnostics, it will soon become very hard for you to find the origin for each of these diagnostics.

For more information about over-defined or inconsistent sketches, see Analyzing and Resolving over-defined or inconsistent Sketches.

 

COLOR and DIAGNOSTIC

SOLUTION:

     
  White: Under-Constrained Element
  The geometry has been constrained: all the relevant dimensions are satisfied but there are still some degrees of freedom remaining.

Add constraints.
   

 

  Brown: Element Not Changed
 
  • Some geometrical elements are over-defined or not-consistent,
  • or the geometry is fixed,
  • or there is either two free or one free and one fixed geometry in the same set.

As a result, geometry that depends on the problematic area will not be recalculated.

Remove one or more dimensional constraints, or, in the case of fixed geometry, unfix it.
   

  Green: Fixed Element
  The geometry has been fixed using the Constraint Definition dialog box or the contextual menu (right mouse button).

 
     
  Green: Iso-Constrained Element
  All the relevant dimensions are satisfied. The geometry is fixed and cannot be moved from its geometrical support.

 
  Geometry before and after being moved:  
   
       
  Purple: Over-Constrained Element
  The dimensioning scheme is over-constrained: too many dimensions were applied to the geometry.

Remove one or more dimensional constraints.
   

  Red: Inconsistent Element
  At least one dimension value needs to be changed. This is also the case when elements are under-constrained and the system proposes defaults that do not lead to a solution.

Add dimensions. Set dimension value(s) properly.
   

Inconsistent and Over-Constrained Elements

If a sketch contains inconsistent and over-constrained elements when leaving the Sketcher workbench a warning will be generated .
  Under-Constrained Elements

If a sketch is under-constrained when leaving the Sketcher workbench, the application generates errors if Generate update errors when the sketch is under-constrained is active. For more information, refer to the section describing how to customize your Sketcher session and more precisely, see Update.

Creating a Constraint Between a 2D and a 3D Element

When you need to create a constraint between a 3D element and a line, for example, this creation may result impossible. This is the case when the projection or intersection resulting use-edge does not give a unique solution. In other words, the use-edge (projection of one side of a pad) corresponds to several limit edges of the side.

As a result, you will not be able to select this 3D element when creating the constraint. You will therefore have to use manually the projection operators.