Users of AutoCAD 2009 and up may encounter system crashes when working with large or dense hatch patterns, especially with 32-bit AutoCAD. Drawings that contain such hatch patterns may crash when opened or when you change layout tabs. The problem occurs because the big hatch patterns use up all your system memory. If you encounter this problem, try setting the HPMAXLINES system variable to a lower value (minimum setting is 100). If that doesn’t work, try setting the VIEWRES system variable to a lower value. If that doesn’t work, upgrade to a 64-bit operating system.

We previously discussed a few issues you may encounter as a result of the introduction of a built-in Layer States Manager as part of the Layer command (AutoCAD 2007 and up) to replace the Express Tool Layer Manager (Lman).

Caption: Built-in Layer States Manager debuted in AutoCAD 2007.

The built-in Layer States Manager will convert layer states created in the Lman Express Tool. However, the Express Tool version allowed more latitude with layer names, so you may end up with layer state names that display as LMAN_INVALIDNAME (xx), where xx is a sequential number. Characters that work in the Express Tool but are not valid in the command version include:

• Pointy brackets (<>)
• Backslash (\)
• Forward slash (/)
• Quotation marks (")
• Colon (: )
• Semicolon (;)
• Question mark (?)
• Asterisk (*)
• Bar (|)
• Apostrophe (')
• Equal sign (=)

The workaround is to use the Express Tool Lman to remove these characters from the layer state names before converting.

Caption: Express Tool Layer Manager (LMAN).

You can do that in an earlier version of AutoCAD. Note that you can access the Express Tool Lman command in AutoCAD 2007 by typing Lman at the command prompt. In later versions, Lman brings up the built-in Layer States Manager.

Last time, we covered the basics of dynamic block creation. This time, we’ll take a more in-depth look at some of the options available when you add a parameter.

Chain
If you want one action to cause more than one change in a block, you can chain parameters so that when you activate one parameter’s actions, the actions of the secondary parameter also occur. The primary parameter must have an action whose selection set includes the secondary parameter along with any objects it will act on. The secondary parameter’s Chain property must also be set to Yes.

Value Set
Value sets allow you to constrain the available values for your block’s size. These take the form of lists of values or allowable increments, with minimum and maximum values. For example, your block may come in lengths of 24”, 36”, and 48”. Or perhaps the length can vary from 10 cm to 50 cm in increments of 5 cm.

You can specify a value set when you create a parameter. When you select this option, you are first asks to choose either the increment or the list method.

Caption: The first step in creating a value set is specifying whether you want a list or an increment. Prompt here is for a Rotation parameter.

AutoCAD then prompts for the values. For a list, you are asked to enter a list of values (the type of value will vary depending on the parameter). Values are separated by commas.

Caption: Rotation parameter asks you to enter list of angle values.

For an increment, AutoCAD first prompts for the increment, then for a starting and ending value.

Caption: Linear parameter asks you to enter an increment for distance.

You can also select an existing parameter and use the Properties palette to create the value set (and change other dynamic block properties, for that matter).

Caption: Use the Properties Palette to add value sets to existing parameters in dynamic blocks.

Base
This option creates a base point parameter that determines the base point for the block.

Name
You can change the name of a parameter, but you may find it more useful to keep the parameter’s original name so you know exactly what parameter a particular block uses. This option can come in handy, however, if you have two instances of the same parameter. In that case, you may want to make each one more descriptive—for example, Move Nut and Move Bolt.

Dynamic blocks can be inserted and scaled just like regular blocks. However, sometimes the dynamic grips may disappear after you scale a block nonuniformly. The workaround is to change the scale of the block in the Properties palette. Open the Properties palette. Select the block, and under Geometry, set the Scale X, Y, and Z values to the same value.

If you use the Value Set increment option and set it to 1” or something similarly small, you will see a lot of tick marks indicating the increments.

Caption: With an angle increment set to 2, this Rotation parameter (Angle) displays an abundance of tick marks.

Set the system variable BTMARKDISPLAY to 0 to make the increment indicators disappear.