There are several things you can do to ensure the goal seeking operation succeeds.
The following best practices apply when drawing, sketching, and dimensioning 2D geometry.
Add geometric relationships--As you draw or sketch, IntelliSketch adds geometric relationships automatically. You also can use the Relationship Assistant command to add geometric relationships to profiles so that the geometry is fully constrained. Fully constrained geometry ensures more predictable results.
The Relationship Assistant is particularly useful when working with geometry that you import from other systems.
Add driven variables and dimensions (for the Goal)--For a variable value that you want to be able to modify or calculate, add a driven dimension, or create a 2D area object with the Area command (but not for synchronous sketches), or define a formula using driven variables. The value of a driven variable or dimension is controlled by the element it refers to, or by a formula or variable you define.
Add driving variables and dimensions (for the Variable)--For a value that you want to allow to change, add a driving dimension or variable. The value of a driving variable or dimension controls the size, orientation, or location of an element. Changing this variable must cause the Goal to change, too.
Note:
Driving variables, which are independent, can only be used for the Variable to be changed.
Driven variables, which are dependent, can only be used for the Goal.
The Variable should be related to the Goal, so that when a change is made to the Variable, it causes the Goal to change through a formula or geometric relationship.
For ordered sketches--Add driven and driving dimensions to sketches created using the Sketch command in ordered mode that can be used by goal seeking to drive changes to a traditional part or sheet metal model.
For synchronous sketches--Add locked (driving) and unlocked (driven) dimensions to synchronous sketches before you extrude the shape to create a 3D object.
To learn about the different types of dimensions, how to recognize them, and how they can be used to control the design, see the following help topics:
For part, sheet metal, and assembly models, you should verify the following properties are available for goal seeking.
For part and sheet metal models, the sketch dimensions convert to PMI dimensions on faces. You can use the Goal Seek command bar to select PMI dimensions directly on the model.
For the most accurate results, set the precision in the File Properties dialog box to the highest possible value (the most decimal places) on the Units tab and in the Advanced Units dialog box.
Verify that a material is applied to the model in the Application menu→Properties→Material Table.
For part models, verify that the Physical Properties dialog box contains the updated properties and units that you want to reference in goal seeking. This dialog box is available using the Inspect tab→Physical Properties group→Physical Properties command.
For assembly models, you can use the Physical Properties Manager dialog box to access the properties for individual parts. This dialog box is available using the Inspect tab→Physical Properties group→Physical Properties Manager command.
Sometimes, if the initial conditions set on the command bar are too widespread, goal seeking cannot find the target value or it may require too many iterations. If you start the goal seeking operation with the value of the Variable set such that the Goal is close to the Target, the iterative process generally will be faster and more successful.
You can use the Variable Rule Editor dialog box, which is available within the Variable Table, to set upper and lower limits on the domain of possible values that can be used for the Variable. You can define a discrete set of values, or a range of values, for a variable. This allows you to restrict design changes to a controlled set of values.
Example:
Example 1--If you are seeking a value for the diameter of a circle or the length of a line, you should set a limit that their value be greater than 0.
Example 2--If you are seeking the diameter of a pipe, then you should set a limit that the outer diameter is greater than the inner diameter.
Example 3--If you are seeking an angle, then you should define a rule that limits the possible solutions to an acceptable range, such as between 5° and 90°, or between 90° and 180°.
For more information, see Define limits for a variable.
The Goal Seek command is an equation-solving algorithm that works through an iterative process to find the target value for a goal. Numerical solution techniques such as these can fail to solve the equation or produce numerical instabilities. The Maximum Time and Maximum Number Of Iterations set in the Goal Seek Options dialog box limit the amount of time that goal seeking will run should it fail to find a solution.
When an equation fails to produce a solution, it may be due to any of these factors:
There may not be a solution for a given set of inputs.
The maximum number of iterations was reached before a solution was found.
The maximum time limit was reached before a solution was found.
You can adjust the maximum time or maximum number of iterations to suit the needs of the particular situation you have. Select Goal Seek Options on the Goal Seek command bar to open the Goal Seek Options dialog box.