Relayering AutoCAD Drawings

In this article you will see how relayering AutoCAD drawings can save you time and money.

You all know that drawing; the one you receive from a client or another firm that is such a mess that it would almost be easier to redraw the whole thing, ALMOST.

So off to the clean up squad it goes to get it's layers, colors, text and blocks sorted and to rid it of useless entities on the "0" layer.

Ah fun.

If you know your way around AutoCAD and the Express tools, you can minimize the time it takes to get that baby into shape.

Drawing Clean-up Steps

Often times what we do is clean up the drawing to where it is "good-to-go" with our layers, colors and title block.

That way we know we can incorporate it into our own design or plot it out and it will look close to something we actually designed.

I can think of one word that best describes the drawing de-clutter process, "relayer".

Basically this involves moving existing entities from one layer to your preferred layer.

Here are some steps we take and tools we use when relayering AutoCAD drawings to clean up messy out-of-office CAD files:

1. Get an overall view of the drawing.  Unless you need to deal with a drawing that has several Paper Space viewports that may need attention (another article all together), click the "Model" tab at the bottom of your drawing to go to model space.  Most of the drawings we need to declutter or relayer, are plan views.  There are times where we need to use an existing cross-section or elevation but that is rare.  So for the most part, cleaning up a drawing from model space works best.
   
   
2. Thaw and turn on all the layers in the drawing to see what you are dealing with.  Make use of the LAYTHW and LAYON commands to make everything in your drawing visible.  For those with older versions of AutoCAD, I made a little macro that does a great job of freezing and thawing all the layers in a drawing.  I use this all the time in lieu of the Layer Isolate/Unisolate Express tools. Some may like to just "Export" the drawing they received "as-is" to a new drawing, which pretty much eliminates much of the frozen mess and exports a WYSISYG type of deal, but I like to thaw and turn on all the drawing layers so I can see if maybe there is a layer in there that we may need.
   
   
3. Check the drawing out.  Pan around and zoom in to see the different areas of the drawing.  There may be only a few entities you need to get rid of to make the drawing presentable.  A quick peak around your AutoCAD drawing will give you an idea of how much work is involved with cleaning it up to your office CAD standards.
   
   
4. The next thing I do is figure out what layers I might be able to salvage, re-use or re-name. For instance, my standard layer for a wall might be “A-Walls”. When relayering AutoCAD drawings, if there is a layer within the drawing, say a layer called simply “Walls”, I will try and re-use and re-name it. Using the LAYMRG Express Tool is also a great way to move an entire layer of entities to one of your standard layers. Be careful here though, whoever created the drawing may very well have put doors, windows, walls, text, etc., all on the same layer. It is a good idea to freeze all layers and thaw them one by one to be sure the LAYMRG command will be useful when relayering AutoCAD drawings.
   
   
5. Once I have my layers within the drawing I start moving items to those layers. Hopefully this will not take very long because of the layer re-naming process. Go through the drawing selecting the “obvious” items (like walls, windows, doors, text…etc) and change their properties as needed to place them on the appropriate layer.
   
   
6. After I have completed the above steps, or at least went through several passes to get the drawing to start to look more like one that I have put together, I would freeze the layers that are “mine” to see what is left, for instance going back to the “A-Walls” example. Once I have created this layer (or re-named/merged an existing layer) and have moved the obvious items to this layer, I would freeze it. I know, you are thinking how can this help? This step helps to get some of the clutter out of the way. Once this layer has been frozen you can see what items have been missed. If you have missed a few lines, just select them and move them to the “A-Walls” layer. AutoCAD will tell you that you are moving items to a frozen layer but you already know that.
   
   
7. Once you have completed the above step you will either have a blank screen or you will have a few items that do not have a layer yet. This is where your layer standards come in. Just take a look at what you have left and create the appropriate set of layers. Move the items to the correct layers, then freeze that layer also. My goal is to get an empty screen with every item on a frozen layer to match my CAD standards. At this point when relayering AutoCAD drawings, the only layers that should be on are:
   
   a.) empty
   b.) not part of my CAD standards.
   
   
8. Now the big command…PURGE; an integral step when relayering AutoCAD drawings. Type in PURGE and select PURGE ALL (be sure that the PURGE nested items box is checked). This should get rid of all the unwanted items within the drawing. Your drawing should be nearly de-cluttered. I say nearly because we have not dealt with those pesky one-eyed blocks that have not been created “bylayer”.
   
   
9. If you run into a block that doesn’t seem to act right, meaning you put it on a layer and then freeze that layer and the block does not disappear, this means the block has not been created “Bylayer”. There are two ways to remedy this situation. The first is to explode the block and then select all the elements and place them on the correct layer. I don’t recommend this because then what is the point of having blocks in a drawing. I would only explode as a last resort.
   
   
10. The best option for dealing with blocks is to “re-define” them. The easiest way to do this when relayering AutoCAD drawings, is to use the “In-Place” block editor. Just double click on the block and it will open the editor dialogue box. Find the correct block and select it. When the editor opens up, select all the elements and put them on layer “0” and make them “Bylayer” in color. Select the close button on the block editor. Do this for each block that you need to fix.
    
    
11. Once this has been done run the Purge command again to finalize the de-cluttering of your CAD file. 

Relayering AutoCAD drawings is the best way to save your office money compared to redrawing a CAD file from scratch, and in a fraction of the time.

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