Patterns

To create multiple instances (copies) of a feature or features in a regular pattern (or to fill a prescribed area) you can select the items and then use the pattern tool (or RMB > pattern).

 

Patterns can be linear – line or grid, radial – referenced to an axis, fill an area or follow a curve.

All patterns need references to define their direction and characteristics.

The dashboard controls firstly define the type of pattern, this will then dictate which direction reference boxes are displayed.  The number of copies in each direction is also displayed.

Remember to use your right click menus as well

 

Simple patterns

These pattern types are the simplest to set up but do not give any control over the geometry in the individual copies.

Direction – choose a plane/surface to signify a direction

Axis – choose an axis to signify the centre of rotation

Fill – choose a sketch as a boundary to fill

Curve – choose a sketch to follow

 

Direction Pattern direction

When setting up a Direction pattern you can set a rotation element though the above drop down list

 

Axis pattern, equal spacing

 

 

 

Geometry Patterns

See Pattern regeneration time discussion below

Particularly useful for patterns which are comprised of instances created from a group of features or a high numbers of instances. This pattern simply replicates the set of surfaces which generate the original form therefore reducing the feature regeneration time.

Model tab > Pattern drop down list > Geometry Pattern

 

Continue as with simple patterns

 

 

 

 

Patterns with geometry control

A Dimension pattern will allow you to control the geometry and position for individual copies.  This patterns form is dictated by the direction references you choose – linear, radial or curve.

 

Driving dimensions

As with any other features, a pattern requires references.  The important concept to understand with patterns is that you choose parameters [dimensions] which place the original feature to describe the direction or nature of the pattern.

The chosen dimension also indicates the positive direction.  If you want the pattern to increment in the opposite direction you need to input a negative figure.

For a linear pattern [as above] dimensions in X and Y which place the original feature are selected to indicate the two pattern directions.  These references are placed in the two Dimension boxes –    Direction 1 and Direction 2.

 

Radial pattern

The driving dimension for a radial pattern [below] is the angular dimension placing the original feature.

The dimensioning scheme for a radial Dimension pattern must be carefully considered.  The default linear placement of the sketch in the below left image will conflict with the radial pattern.  The modified dimensioning scheme will produce a successful pattern.

 

Incrementally changing instances

You can also change the parameters of a feature as it is copied – eg. each instance decrease progressively in height through the pattern.

In the above example an extrusion has been patterned around the axis of the base cylinder.  This pattern has then been altered so that as each instance of the original extrusion is created, the height dimension, the diameter dimension and the distance from the axis dimension are adjusted.

The parameter you wish to change is included in the appropriate direction box and the incremental adjustment input.  In the above example the height dimension, diameter and the distance from the axis dimensions are collected in the Direction 1 box after the initial angular driving dimension.

 

 

Hide instances – pick black preview dot whilst creating the pattern to hide that instance

Reference pattern – if you reference a new feature to a pattern instance, say filleting  the edge of a patterned hole, and then pattern the new feature, the system will recognise the relationship and create the new pattern as a Reference pattern following the underlying parent pattern instances

 

Unpattern – if you pattern a group of features, the pattern can be ‘exploded’ so that the instances are independent.  RMB the pattern in the Model Tree.

 

Pattern regeneration time – patterns can take a long time to regenerate, these methods can save you time;

• Suppress pattern whilst working on other things
• Can you consolidate the patterned form as a neutral model – good for assembly patterns.
• Create a surface copy of the feature.  Solidify inside the volume.  Group the surface and solidify feature together and pattern the group
• Use a Geometry pattern

 

Modeling a large pattern with surface copies

When you need to model a part with a large pattern of (grouped or complex) features you might consider getting off the beaten track and instead of  using standard Creo features and patterns,  use surface copies.

Process:

• create the first feature or group of features
• copy all surfaces associated to those features using the Seed and Boundary method
• pattern the copied surfaces
• solidify the patterned copied surfaces

This yields a much more stable, faster and smaller part altogether.

 

Pattern Examples

 

• Curve projected on surface
• Point just in from end of curve – needs a dimension
• Ref geom to set up Revolve
• Features grouped
• Dimension pattern of group, dimension to initial point used as driver
• Revolve dimension added to Direction 1 list to vary

 

 

• Angled plane DTM11 is foundation of pattern rotation element
• DTM12 has vertical offset distance from base plane
• Revolve cut and fillet created
• Features from DTM11 to fillet grouped
• Dimension pattern created
• Direction 1 – angle for DTM11
• Direction 2 – offset distance to DTM12
• Revolve diameter also added to direction 2 to reduce revolve diameter in direction 2