Understanding the Frozen Layer Option

Understanding the Frozen Layer Option
As mentioned earlier, you may want to turn off certain layers to plot a drawing containing only
selected layers. But even when layers are turned off, AutoCAD still takes the time to redraw
and regenerate them. The Layer Properties Manager dialog box offers the Freeze option; this
acts like the Off option, except that Freeze causes AutoCAD to ignore frozen layers when
redrawing and regenerating a drawing. By freezing layers that aren’t needed for reference or
editing, you can reduce the time AutoCAD takes to perform regens. This can be helpful in
large, multi-megabyte files.
Be aware, however, that the Freeze option affects blocks in an unusual way. Try the following
exercise to see firsthand how the Freeze option makes entire blocks disappear.
1. Close the Plan file, and open the 07b-plan.dwg file from the sample files. Metric users
should open 07b-plan-metric.dwg. This file is similar to the Plan file you created but with
a few additional walls added to finish off the exterior. Also note that the individual units are
blocks named 07a-unit-metric. This will be important in a later exercise.
2. In the Layer Properties Manager dialog box, set the current layer to 0.
TIP You can freeze and thaw individual layers by clicking the Freeze/Thaw icon (which looks like
a sun) in the layer list in the Layers toolbar.
3. Click the yellow lightbulb icon in the Plan1 layer listing to turn off that layer, and then click
OK. Nothing changes in your drawing. Even though you turned off the Plan1 layer, the layer
on which the unit blocks were inserted, the unit blocks remain visible.
4. Use the Layer Properties Manager dialog box to turn off all the layers. You see a message
warning you that the current layer will be turned off. Click No to turn off the current layer,
and then close the Layer Properties Manager by clicking OK. Now everything is turned off,
including objects contained in the unit blocks.
5. Open the Layer Properties Manager dialog box again, and turn all the layers back on.
6. Click the Plan1 layer’s Freeze/Thaw icon. (You can’t freeze the current layer.) The yellow
sun icon changes to a gray snowflake, indicating that the layer is now frozen.



7. Click OK. Only the unit blocks disappear.
Even though none of the objects in the unit blocks were drawn on the Plan1 layer, the entire
contents of the blocks assigned to the Plan1 layer are frozen when Plan1 is frozen.
TIP Remember that to select all the layers at once, you can right-click a blank area of the Layer
Properties Manager dialog box and then choose Select All from the shortcut menu.
You don’t really need the Plan1 layer frozen. You froze it to see the effects of Freeze on blocks.
Do the following to turn Plan1 back on:
1. Thaw layer Plan1 by opening the Layer Properties Manager dialog box and clicking the
snowflake icon in the Plan1 layer listing.
2. Turn off the Ceiling layer. Exit the dialog box by clicking OK.
The previous exercise showed the effect of freezing on blocks. When a block’s layer is frozen, the
entire block is made invisible, regardless of the layer assignments of the objects contained in the block.
Keep in mind that when blocks are on layers that aren’t frozen, the individual objects that are a
part of the block are still affected by the status of the layer to which they’re assigned. This means
that if some objects in a block are on a layer called Wall, and the Wall layer is turned off or frozen,
then those objects become invisible. Other objects with the block that aren’t on the layer that is off
or frozen remain visible.