LT Unlimited

Collapse Layer Filters Pane

One of the improvements to the Layer Properties Manager introduced in LT 2009 was the ability to collapse the layer filters pane, located on the left side of the palette.

In this drawing, there aren't any layer filters, so I don't need to see the pane all the time. Instead, I'll use the double-arrows at the right of the pane to collapse it, enabling me to see more layer properties at once, or to show the same information in less space.

Even though the filters pane is collapsed, you can still access them with the button highlighted in red in the above image.

And if you want a compromise between the default filter pane size and total collapse, you can move the bar between the filter pane and the layer list to resize it.

Layer Tools (formerly known as Express)

Full AutoCAD ships with a set of commands called Express Tools, which are little routines that have been around forever but never managed to make their way into the core program.

Sometimes, though, a command (or set of commands) proves so popular that the team moves it over to become part of the base program. Then they show up in LT too, even though the rest of the Express Tools aren't available.

The most obvious examples of this are some of the Layer Tools. They're on the Layers II toolbar, or the Layers panel of the Home tab of the Ribbon. These commands let you control a layer's visibility and other properties by clicking on an object on that layer, instead of having to track it down in the Layer Properties Manager. Even better, the visibility commands work on objects in blocks and xrefs too.

Here are the Layer tools, introduced in 2007, that were formerly only part of Express Tools:

• Layer Off (LAYOFF)
• All Layers On (LAYON)
• Layer Freeze (LAYFRZ)
• All Layers Thaw (LAYTHW)
• Isolate Layer (LAYISO)
• Un-Isolate Layer (LAYUNISO)
• Lock Layer (LAYLCK)
• Unlock Layer (LAYULK)
• Merge Layers (LAYMRG)
• Delete Layers (LAYDEL)
• Copy Objects to New Layer (COPYTOLAYER)
• Layer Walk (LAYWALK)
• Layer Match (LAYMCH)
• Change to Current Layer (LAYCUR)
• Isolate to Current Viewport (LAYVPI)

Get Rid of Unwanted Layers

There are several ways to rid yourself of unwanted layers in AutoCAD LT.

First up, the Delete button in the Layer Properties Manager. This is useful when you only have one or two specific layers you want to get rid of -- otherwise it's a little tedious. You also can't delete a layer if it has anything on it, whether in the main drawing or in a block reference.

So if you want to delete multiple layers at a time, check out PURGE. It will go through your drawing and remove all unused layers, so you don't have to guess which ones might be eligible for deletion. Purge has a checkbox at the bottom to "confirm each item to be purged" -- unless you feel like clicking "OK" for every single layer to delete, you'll probably want to uncheck this.

But what if that layer just won't purge? It must have some geometry on it somewhere, or you could just delete it. But maybe those lines/arcs/whatever are hard to find, or nested in one of the hundreds of block definitions in the drawing, or...you get the picture.

You could use QSELECT to get all objects on that layer, and then purge or delete it, but if the only geometry on that layer exists in a block reference, this method won't work.

Instead, try two former Express Tools (LT 2007 and up): Layer Merge and Layer Delete. Layer Delete (LAYDEL) will blow away any layer you want, along with any objects that might exist on that layer. Using it is a little dangerous, since you don't ever get to see what was actually deleted.

Layer Merge (LAYMRG), on the other hand, combines your unwanted layer with another that's already in the drawing. The layer definition goes away, but any geometry that was on it gets moved to the other layer. So if I were to start the command, select layer HAM as the "layer to merge" and layer CHEESE as the "target layer" (hey, it's almost lunchtime), all objects on HAM would be moved to CHEESE and HAM would be deleted.

It seems to be popular to use layer 0 as the target layer, so you don't get any strange objects on your existing defined layers.

Copy Layer Table to Excel

I'm on vacation this week, technically, but I was checking out the newsgroups and saw a really neat tip that I didn't want to forget about before I go back to work on Monday.

Over on the LT discussion group, a user asked how to export a list of layers & layer properties to Excel. John Schmidt replied,

<Right-click> -> Select All in the layer manager, then <Ctrl><C> to copy to
clipboard, then Paste into Excel.

Sure enough, it works. I found that you have to be a little careful when selecting the layers if you're using LT 2009, with the new Layer Palette, since it sometimes thought I wanted to copy objects from the drawing. But other than that, it's a quick and easy way to pull a layer list out of a drawing.

Freeze in Current Viewport

In addition to globally controlling layer visibility with freeze/thaw and on/off, you can also control layer display in individual viewports with the "freeze in current viewport" property. (NOTE: You must be in paperspace or in an active paperspace viewport to use this -- it doesn't work in modelspace.) This allows you to show different aspects of the same model in one file, which you might need with demo/new plans, or partial/enlarged plans.

Freeze vs. Off

Back in the days of slow computers, the difference between FREEZE and OFF was very important. Freezing something allowed AutoCAD to ignore it during zooms and regens, so the program could work faster. These days, computers are fast enough that the time savings are very small, so the rules for whether to freeze a layer or turn it off have changed somewhat.

Now, I find it more convenient to use FREEZE for layers I want permanently off (say, architectural door tags), while OFF is for temporary invisiblity (like turning off rebar to hatch a concrete section).