Frequently Asked Questions
Copy, Pattern, Mirror, and Groups

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Topics:
  1. Patterns
  2. Copy and Mirror
  3. Local Groups and User Defined Features (UDFs)

Patterns

[List of Topics]

Copy and Mirror

[List of Topics]

Local Groups and User Defined Features (UDFs)

[List of Topics]

Patterns

* What are the benefits of using patterns?

* What are the differences between Value, Relation, and Table driven patterns?

Dimensions are based off the previous instance for value driven patterns and relation driven patterns with relations using a memb_i relation. Dimensions are based off the same references as the leader for table driven patterns and relation driven patterns using a memb_v relation.

The number of instances of the pattern can more quickly be modified with value and relation driven patterns by modifying the number of instances parameter(s). The pattern table must be edited to change the number of instances.

* How can the leader of a pattern be determined?

The leader of a pattern is the original feature selected for patterning. It can be determined by using Modify, Value and selecting any instance of the pattern. This will show the dimensions for the selected instance and also the dimensions of the pattern leader.

Alternatively, Info, Feat Info of any instance will display a line similar to one of the following:

LEADER OF A (5 X 5) DIM IDENTICAL PATTERN
or
MEMBER (4, 5) IN A (5 X 5) DIM IDENTICAL PATTERN

In the first case, the feature is the pattern leader. In the second case, the selected feature is an instance.

* What is the difference between the Identical, Varying, and General pattern options?

The general difference between Identical, Varying, and General is the complexity of the feature geometry calculation. This categorization allows the possibility for significant regeneration time improvements. Identical patterns are ideal for simple patterns because they regenerate the fastest of the three types, and General patterns, although they regenerate the slowest, allow for the most complex patterns.

When creating patterns, answers to the following questions will indicate which option should be chosen:

Refer to pages 8-2 through 8-4 of the Part Modeling User's Guide for Release 16.0 for additional information.

* What does the message prompt "Select pattern dimensions for FIRST direction, or increment type." mean?

First, this prompt is asking for dimensions to be selected to increment the pattern in one of possibly two directions. One or more dimensions may be selected in each direction. By choosing more than one dimension in a particular direction, the feature(s) in the pattern can be modified in multiple ways. For example, each successive instance of a pattern of holes may have an offset dimension and an increment in diameter.

Second, this prompt is asking for a Value, Relation or Table to be chosen from the menus as the increment type.

* When deleting a member of a pattern, why is the leader also deleted?

The Delete command will delete the entire pattern including the leader. To delete only the pattern, use the Del Pattern command. To delete only one instance of the pattern either modify the number of instances or Redefine the pattern To Table and delete the instance row from the pattern table.

* How can a rotational pattern of a feature be created?

The key to creating a rotational pattern is to have an angular dimension to increment. The best method to incorporate an angular placement dimension with a feature is to use a Make Datum or what is commonly known as a "datum-on-the-fly" while creating the original feature. Use the Make Datum command to orient the feature in sketcher for either the sketching plane or for the horizontal/vertical reference plane. Make sure to either align or dimension the section to this Make Datum plane if chosen as a reference plane. The Make Datum plane should be Through the axis of revolution and at an Angle to an existing plane. This angle is now incorporated into the feature and can be selected as the incremental dimension for the pattern.

* How can a rotational pattern of several features be created?

  1. Ref Pattern: If the pattern consists of two features, such as a counterbored hole, then the technique in "How can a rotational pattern of a feature be created?" can be used for the first feature. After the first pattern is created, a Ref Pattern of the second feature can be created.
  2. Local Group (no make datum): If the pattern consists of two or more features, a local group of the features can be created. In this case, a Make Datum should not be created for the first feature. Instead, a datum plane feature with an angular dimension should be created as the first feature in the group. Then all features in the group should only reference either the datum plane, the axis of rotation, or any plane normal to the axis of rotation. Once the local group is created it can be patterned using Feature, Group, Pattern.
  3. Surface Transform: If the features to be patterned consist of either complex features or features which can not be used with the local group method above due to dimensioning constraints, then using the Surface, Transform command is the most appropriate technique. This method is much more efficient in these two cases because it only needs to copy the feature surface geometry. It is similar to creating an Identical pattern as opposed to a General pattern. The Surface, Transform method involves first creating a Surface, Copy of the surface of the features, then creating a Surface, Transform of the Surface, Copy, patterning the Surface, Transform, and finally, creating a Ref Pattern of a Tweak, Patch feature.

* How can one instance of a pattern be modified?

To modify a single instance of a pattern, the pattern must be Table driven and the dimension to be modified must be included in the pattern definition. The instance of the pattern may be modified by choosing Modify, Value and picking a dimension, or by choosing Modify, PatternTable, Edit and editing the table directly.

* What are the benefits of using Table driven patterns?

* How can a pattern table be created from an existing Value driven pattern?

Choose Feature, Redefine, select any member of the Value driven pattern, choose Pattern from the REDEFINE menu, and then choose To Table. After entering a name for the pattern table and choosing Done/Return, the pattern will be converted from Value driven to Table driven.

One of the benefits of this method is quickly creating a large number of pattern instances as a Value driven pattern, then modifying individual instances in the Table driven pattern.

This method also preserves all children of the original Value driven pattern.

* How can different Family Table instances of a part use different configurations of a pattern?

Table driven patterns can have several different configurations of the pattern which can be switched manually using the Modify, PatternTable, Switch command. They can automatically be switched in a family table instance by adding the pattern table to the family table using Family Table, Add Item, PatternTable. Then Edit the family table and for the part family table instance, enter the name for the alternate pattern table configuration. When the part family table instance is retrieved, it will have the alternate configuration.

Seer "Suggested Technique For Using Pattern Tables in Family Tables" for a detailed walk-through of this procedure.

* How can a pattern be created along a complex trajectory?

On Curve datum points are useful for this type of pattern because they have a dimension specifying either the measured length or percentage of the entire length along a curve. First create a datum curve (Composite curve if more than one segment) representing the trajectory. Then create an On Curve datum point using either the Offset, Length Ratio, or Actual Len options. Then create other features referencing this point (the features should be created so they all move correctly when the datum point dimension is modified.) Lastly create a Feature, Group, Local Group of the datum point and the features to be patterned and use Feature, Group, Pattern to pattern the group using the point's dimension.

See "Suggested Technique for Creating a Pattern Along A Datum Curve" for a detailed walk-through of this procedure.

* What is the difference between Feature, Del Pattern and Group, Unpattern?

Del Pattern removes all pattern instances of a patterned feature but leaves the leader feature.
Unpattern removes the pattern definition for Group patterns, but leaves all pattern instances intact as separate independent groups.

* Why are some instances of a pattern which should go Thru Next created as if Thru All?

This may occur for Varying patterns because the termination surface for each instance being created is determined by the direction of the leader instance. Patterns exhibiting this behavior should be redefined to the General pattern option.

* Why are some of the dimensions chosen for the pattern increment not changing between instances?

Patterns created with the Identical option will ignore dimensions selected to vary the section or size of the feature. Varying or General should be chosen instead. Refer to "Creating the Pattern" on page 8-19 of the Part Modeling User's Guide for Release 16.0.

* Why does adding a column in a pattern table for an additional dimension have no effect?

For a dimension to be included in a pattern table for driving a pattern (this includes files being imported using Read from the PATT TABLE menu), the dimension must be selected when creating the pattern. If the pattern has already been created, it must be recreated to add an additional dimension. Refer to the middle of page 8-20 of the Part Modeling User's Guide for Release 16.0.

* How can the pattern dimension symbol be renamed or modified?

The pattern dimension symbol cannot be modified. Use a relation to set the pattern dimension to a parameter name if naming is necessary. Refer to the second bold note on page 10-7 of Part Modeling User's Guide for Release 16.0.

Copy and Mirror

* What is the difference between Copy, Independent and Copy, Dependent?

Independent copied features are completely independent of the features they were copied from. Modifying, redefining, or deleting the original feature will have no effect on its independent copies.

Dependent copied features, on the other hand, are dependent on all dimensions which are not selected as variable dimensions at the time of the feature copy. Dependent copied features are also dependent on the section of the original feature. This means if the section of the original feature is redefined, modifications to the way the section relates to the part will not be possible. In other words, dimensions to the part geometry may not be added or deleted and section entities may not be aligned or unaligned from the part geometry. However, additional section entities may be added or dimensioned, and existing entities which are not dimensioned or aligned to the part may be deleted. All of these changes will affect the dependent copy.
Deleting or suppressing the original feature will only cause a dependent copied feature to fail if the original feature has a sketched section or if dependent copy has some other parent/child relationship to the original feature. For features without sections (such as Straight Holes) the original feature may be deleted leaving the dependent copy intact.

* Why does Pro/ENGINEER behave as if copied features are part of a group (such as when suppressing or deleting)?

When more than one feature is selected for a feature copy operation, a local group of the features is created. Refer to the middle of page 9-28 of the Part Modeling User's Guide for Release 16.0.

* How can a feature created using Copy, Dependent be made independent of the original feature?

A dependent copy of a feature can be made independent using one of two methods:

* What is the difference between Feature, Copy, Mirror, All Features and Feature, Mirror Geom?

Feature, Copy, Mirror, All Features makes a mirror of each feature which allows the ability to independently modify the copied features so they have dimensions different than the original features.

Feature, Mirror Geom creates only one merge feature which is a representation of the entire geometry created before the merge. This means any modifications to the copied feature will affect the original features as well.

* Why are features inserted or reordered into a range of features which have been copied (mirrored) not automatically copied?

Feature, Copy (mirrored or otherwise) is a one time command which copies the features at the moment it is executed. If additional features are inserted or reordered into the original range of features, they will not be reflected in the range of copied features. To achieve this effect, either:

  1. copy the one new feature
  2. recreate the Feature, Copy
  3. use Feature, Mirror Geom for mirrored copies.

Feature, Mirror Geom works because it is a feature which mirrors all the geometry before it whenever it is regenerated.

* What are the benefits of using Surface, Transform to copy surface and datum curve features?

Surface, Transform is preferable to Feature, Copy in many cases because it only copies the final feature geometry of the surface or datum curve. This makes it extremely efficient for regeneration times and tracing the construction of a part. It also has the added benefit of not having to respecify references to parents. This is especially apparent when copying features with complicated geometry and complex relationships to model geometry. In conjunction with Surface, Copy and Tweak, Patch, it can be used in virtually any circumstance. See "Suggested Technique for Creating a Radial Pattern Using a Surface Transform."

* Can I copy a feature from one model to another?

Features can be copied from one model to another by selecting FromDifModel from the COPY FEATURE menu. This option is only available when New Refs is selected from the the same menu. Relations are copied to the new part if they do not reference dimensions of features that are not included in the Copy option. The feature will regenerate with the accuracy of the model into which it is copied.

Local Groups and User Defined Features (UDFs)

* What are some of the benefits of using groups?

For Local Groups and User Defined Features:

For User Defined Features only:

* What is the difference between a UDF and a Local Group?

A Local Group can only be used on the currently active model. A User Defined Feature (UDF), created using Group, Define and Group, Make can be used on the current model or any other model.

Local Groups are more easily created because placement references do not need to be specified. By creating a local group of several features, they can be made to behave as one feature. The most common use of local groups is for creating patterns of several features.

UDF's allow much more flexibility at the expense of some preparatory work during definition of the group using Group, Define. UDF's also allow the use of group programs and tables for making alternate configurations of a range of features. When Table driven, UDFs can be used in conjunction with Family Table instances for replacing the configuration of a range of features between different model instances. See "What are some of the benefits of using groups?"

* What is the difference between Define and Make?

Define creates a UDF definition file. When Define is chosen, the user will be prompted to create prompts for each of the references, select variable dimensions, and optionally create a group Table or Program. Make places the UDF created with Define onto the current model. Feature, Create, User Defined is equivalent to Make.

* What is the difference between Subordinate and Stand Alone?

These are options chosen during the Group, Define process. They determine whether the part the group is defined on will be retrieved and shown in a window during placement of the group.

Subordinate makes the group dependent on the part it was created on. When placing a group defined with Subordinate, the part the UDF was defined on will be retrieved and shown in a window to highlight the references during placement. The part will not be able to be DBMS, Erased while the group is in session. Also, if any of the reference features are deleted from the part, the group definition will be invalidated. Subordinate does not, however, mean the group will update to reflect changes in the original features. UDF Driven must be chosen during group placement for this effect.

Stand Alone makes the group independent of the part it was created on. When this option is chosen, the prompt "Do you want to save a reference part? (Y/N):" will be displayed. This gives the option to save a copy of the current model which will behave as a model the group is subordinate to. If "Y" is entered for this prompt, a part named ###_gp.prt (where ### the name of the group) will be stored. The group will behave as if it is Subordinate to this reference part. If "N" is entered no reference model will be stored, which means the user placing the UDF must rely on clearly written prompts for the references and variable dimensions. Answering "N" may be preferable for saving disk space and group retrieval time.

* What is the difference between Independent and UDF Driven?

These options, which are specified when placing a UDF when using Group, Make, determine if the placed group updates to reflect the state of the features on the reference part. The reference part is either the part the group was created on when defined with Subordinate or the part saved when the group was defined as Stand Alone and a reference part was saved. For changes in the original features to show in a group made with the UDF Driven option, the part must have its groups updated using Group, Update.

* What is the procedure for updating a group which is UDF Driven?

When the original features used for the group definition are modified, the placed UDFs will not automatically update. To have the changes reflected in the placed UDFs, choose Group, Update and Regenerate in the part with the placed UDFs.

* How can a UDF Driven group be made independent?

Feature, Group, Disassociate. This command should be chosen before ungrouping any group which is UDF Driven to allow dimensions to be changed to Normal status (as opposed to Read Only or Blank.)

* When creating a Local Group, must all the features be sequential in the regeneration order?

Yes, all features in a local group must be sequential. Use Feature, Reorder to make features sequential if they are not. If the selected features are not in sequential order, the prompt: "Group all features in between? [N]:" will be displayed. Entering "N" will abort the local group definition.

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