User Guide
User Guide
User Guide

Hatching and Patterning

Patterning is the repeated placement of a hatch line or cell through a closed area at a specified interval (spacing), scale, and angle. You can place patterns on any designated level.

When using a hatching or patterning tool with the tool setting Method set to Flood, Union, Intersection, or Difference, turning on Dynamic Area along with Associative Pattern lets you create patterns that regenerate themselves when their bounding elements are modified. As well, you can create single associative patterns with disjoint regions.

In DWG workmode, by default, area patterning is replaced by AutoCAD pre-defined hatching. The Pattern field in the Pattern Area settings window is a combo box which, by default, lists the patterns in the DWG pattern file "areapat.pat". This file contains a DWG pattern definition for each pattern cell in the supplied cell library, "areapat.cel".

To select a different DWG pattern file, key in its full file specification — path and filename — in Pattern File or click the adjacent magnifying glass icon to browse the file system.

A corresponding DWG pattern file is supplied for each of the important, supplied pattern cell libraries — "archpat.cel", "areapat.cel", "geompa.cel", "igespats.cel", "linepa.cell", and "utilpat.cel". These DWG pattern files have the same filename as their cell library counterparts except their extension is .pat.

Controlling the display of patterns

Elements — either lines or cells — in a pattern are designated as pattern elements.

To turn the display of patterns on or off in one or more views
  1. From the Settings menu, choose View Attributes.
    The View Attributes dialog box opens.

  2. From the View Number option menu, choose the number of the desired view.

  3. Turn Patterns on or off.

  4. Click the Apply button.

  5. Repeat steps 2–4 for additional views.

To turn the display of patterns on or off in all views
  1. From the Settings menu, choose View Attributes.
    The View Attributes dialog box opens.

  2. Turn Patterns on or off.

  3. Click the All button.

Placing patterns in the design

The tools in the Patterns tool box are used to pattern the area inside a closed element with the Area attribute of Solid, the fence, the intersection, union, or difference of multiple elements, or the area enclosed by a set of elements. Elements used to create the patterned area can be in either the active file, one or more references, or a combination of both.

The Hatch Area tool and Crosshatch Area tool are used to place lines (hatch lines).

Hatching (left) and Crosshatching (right)


The Pattern Area tool is used to place the cell designated as the Active Pattern Cell. For example, a wall face can be patterned with a brick cell for a more realistic appearance.

Examples of placing the Active Pattern Cell


Area patterning can be a time-consuming operation, depending on the complexity of the Active Pattern Cell and the size of the patterned area. The time also depends on the number, intricacy, and levels of hole elements within the area. More intricate elements may require several minutes to pattern.

Associative patterns

Turning on Associative Pattern, when you use the Hatch Area tool, Crosshatch Area tool, or Pattern Area tool, causes the pattern to be associated with the patterned element. This means that whenever the element is modified or manipulated, the pattern automatically is updated. The pattern elements are placed on the same level as the patterned element. Turning on Associative Region Boundary, in addition to Associative Pattern, enables you to place the pattern elements on a different level.

If an element that has an associated pattern is rotated or scaled, the associated pattern also is rotated or scaled.

Associative patterns can be created from:

When any of the elements used to create the patterned area are modified, whether they be from the active file or a reference, the associated patterning updates also.

Hatching the shape on the left, with Associative Pattern turned on, means that if you modify it later (right), the hatching updates automatically to the new shape.


Snappable patterns

Turning on Snappable Pattern, when you use the Hatch Area tool, Crosshatch Area tool, and Pattern Area tool, causes the pattern element to be eligible for snapping.

While, in some cases, being able to snap to pattern elements is desirable, in others it is not, since having large numbers of pattern elements in an area may make it difficult to select or identify a particular element.

Excluding areas inside a patterned area from patterning

When you create a shape, circle, or ellipse, defining an area for patterning, you can exclude patterning in regions within this element. You do this by placing other shapes, circles, or ellipses within the outer element. Additionally, you can exclude the areas surrounding text in the patterned region. You have several ways to define the areas for patterning, and those to be excluded.

Setting elements to be Solid or Hole

When you create shapes, circles, or ellipses, you have the choice of setting their Area to be Hole or Solid. This can affect the way that elements are hatched or patterned. Usually, the areas enclosed by “hole” elements, located inside and on the same level as the Solid element, are not patterned. This applies as follows:

Associative Pattern

Hole Elements Inside Element


Are not patterned.


If they were grouped with the solid element using the Group Holes tool — they are not patterned.

If they were not grouped with the solid element — they are ignored and the selected solid element is patterned with no “holes”.

Using tool settings

Tool settings for the Hatch Area, Crosshatch Area, and Pattern Area tools, let you exclude areas in closed elements from being patterned. With each of these tools, Method can be set to:

Using Alternating Area to exclude nested areas from patterning

When you have areas nested inside others, you can pattern alternate regions in one step using the Flood method with both Locate Interior Shapes and Alternating Area turned on. In the example below, the hatching was performed in a single operation.

The Alternating Area setting, in conjunction with Locate Interior Shapes, lets you flood hatch/pattern the nested areas (left) to produce the required result (right) in one step.


Manipulating/modifying excluded regions

When you pattern an area, with Associative Pattern turned on, you can manipulate or modify the elements defining the regions and the pattern will update accordingly to conform to the modified regions.

When you manipulate or modify a shape, or excluded area, that has been hatched/patterned with Associative Pattern turned on (left), the patterning updates accordingly (right).


Patterning disjointed regions

With Method set to Flood, and Dynamic Area turned on, you can pattern disjointed elements. That is, by holding down the <Ctrl> key, you can select a number of enclosed regions to flood hatch or pattern, in one step. These regions highlight dynamically as you move and hover the pointer over the drawing. With this method, you still can use the Locate Interior Shapes and Locate Text settings to exclude areas in the selected regions.

Left: Select the regions to “flood” hatch (<Ctrl>-data points 1–3).

Right: Accept to hatch the selected regions (4).


A single associative pattern region can consist of many disjointed sub-regions. A sub-region may be the smallest area enclosed by many elements or simply the area of a closed shape. A sub-region can contain grouped holes and text elements.

When patterning disjointed regions, turning on Associative Pattern causes the creation of a complex shape that bounds the patterned area. The hatch lines are associated to the complex shape. If you move or modify the original element(s), used to create the complex shape, the complex shape and the hatch lines will not update unless Associative Region Boundary was also on during the patterning operation.

Cells used for patterning

Pattern cells may contain any combination of elements, even text. Cells used for area patterning typically are designed specifically for that purpose.

Pattern cells supplied with MicroStation

The cell libraries “archpa.cel” and “geompa.cel,” in Bentley's "Workspace\system\cell" directory, contain pattern cells that are useful for various area patterning applications.

Examples of cells in “archpa.cel” cell library


Examples of cells in “geompa.cel” cell library


Guidelines for creating pattern cells

Additional pattern cells are created just as all other cells are. Here are some guidelines to follow and restrictions to be aware of when creating area pattern cells:


When patterning along or inside a curved element, the curve is approximated with a series of line segments that are used as “guides.”

The tool setting Tolerance is the maximum distance in working units between a curved element and the approximating line segments used to pattern. If the Tolerance is small, the line segments conform closely to the curve and the approximation is more accurate, but processing time increases. If the Tolerance is large, line segments do not conform as closely to the curve and the approximation is less accurate, but processing time decreases. The setting can be saved.

Left: Tolerance as denoted by “T”. Center: Approximating line segments if tolerance is large. Right: Approximating line segments if tolerance is small.