Layers and XRefs

Different versions have different capabilities concerning XREFs.
Unloading an XREF prevents it form being displayed and should speed things up considerably. Look into VISRETAIN in the help. Once you have your XREF layer setup you can have it persist from session to session. I you need a few combinations, Layer Manager, or whatever their now calling it, can simplify toggling the layer states.

Layer manager seems to allow you to make up different lists of layers, then you can select by listname what you want displayed. I say "seems to" because I fooled around a lot with layer manager yesterday but did not actually try this function. It is in there though (Acad 2005).
- Tom
Happy Trails To You

IF YOU START USING LAYER FILTERS YOU WILL MAKE A LOT OF ENEMIES WHEN YOU SHARE THE FILES

Love that upper case - reminds me of the olden days of teletype machines.
In my case I'm always the sharee, not the sharer.
Layer filters are very useful (which is why they were invented, I guess) for making up different "models" required for different purposes.
From most of the drawings I get to work on, I need to use about 10-20 layers each to make up a grading model from which I will make several dtm's, linework for the bulldozer computer, different linework for the field computer used by the surveyor for layout, different linework for the calibration of a site, etc etc etc.
It is really useful to be able to switch among several different sets of layers using a list for this.
Happy Trails To You

Sorry about the upper case. I capslock for drawings, and forgot to turn it off. When I realized it was on, I didn't change it because I really felt like shouting how much I hate those filters. One of the biggest problems I have in my job is the acquisition of files from architects that have a zillion layer filters (many the same filter with different names) because of the interchange of files between users, some different operators in the architects office, some engineers working with multiple architects' files. Unfortunately simple purging doesn't remove the filters and the layer filters act like a virus, contaminating files every time someone modifies the file with an insertion. The removal process built into autocad is very slow and in some versions of autocad will lock up the software for an extended period of time. A file that should be small (perhaps a simple detail and title block) in the range of a 1-2 hundred kilobytes turns into a monster of 1-2 Megabytes. Email transfers become a significant issue, and I have to strip out the filters because I may extract the detail for use on the relevant job, resulting in new files acquiring the undesired filters. If you routinely strip the filters before forwarding the file, or never forward your files, the issue is moot, however the majority of filter users are not that careful, and many of the recipients are unaware of the existence of the filters, thereby spreading this problem. In fact one architect I know actually was suffering through the common crashes of autocad LT caused by layer filters while I was on the phone with him and I recognized the symptom as being the same one I had seen before I knew about layer filters (I'm a self-taught cad user having only used the small cursory instruction book packaged with the software, and forums like this to learn autocad.) He jokingly asked if I had hidden a camera in his office since I explained the cause and cure so readily without even being there.
Happy Trails wrote:

Create an empty layer filter then import same into the drawing. Of, course you can go get lunch while waiting for layer manager to open/populate.

Right. We have a LISP routine that we have setup to automatically Purge the Filters every time we open a drawing (then it just a question of saving it or not). But they sure do fatten up a drawing - and a lot of people have NO idea that filters do this. Many are amazed when I tell them how much smaller the files become when you do get rid of them.
Regards,
Bruce

I'm a bit old fashioned when it comes to layers. I hate dialoug boxes and avoid them when I can. A carefully named layer system will save a lot of trouble. For instance, all the layer names that I use in a floor plan contain "_FL" at the end of the layer name. So when I want to freeze all my floor plan layers, for none or a dozen xrefed floor plans, at my command line I type:
-La f *_FL
No filters, no mess, and way faster than a dialoug box.
If I want to freeze from a specific xref drawing named "FLR2", I type
-La f flr2|*_fl
Makes my brain happy anyway :0)