I am an old pencil pusher and architectural detailer, recently converted to ACAD. I start all my drawings in our standard template. I have imported some drawings from architects to get floor plans and moulding details. Now my layers are full of over 200 layers that the architects use. When I try to delete them, it will not let me. I get a message that you can not delete layer 0, defpoints, used layers or xref layers. Since my template starts out as a blank page, except for a few layers used for border and text in layout page, I don't know why I can't delete these layers. If I apply layers filter to show all xref layers, it is empty, so that's not it. I think it is linked to blocks, since importing these drawings, I have acquired numerous blocks, some of which are floor plans. How do you delete unwanted blocks? Tried ACAD help, but could not find an answer. Using ACAD 2004. Ah, for the old days, when an eraser could delete anything.
From contributor V:
Immediately upon opening your template drawing, try using the "purge" command. Also try using the Layer Manager to individually delete unwanted layers. Layer 0 and defpoints are standard. I use Architectural Desktop 2004 and there are also several layers that are created by default for walls, etc. by the program.
Good luck with your venture into AutoCAD from paper - it's worth it, despite the frustrations at first. You'll find this site very valuable for problem solving, philosophical debate on the pros and cons of paper verses CAD, plus a good splash of humor along the way.
Are you trying to "delete" the layer using the Format > Layer > Delete command? If so, ACAD won't allow some layers to be deleted, which can be frustrating.
Use either the Layer Manager or the Purge command (type purge) and look at the command line to see what layers are being offered for purging. Also, when I'm presented with this problem, I try exploding the entire drawing, though only as a last resort. Before deleting or purging, make sure that you're only purging layers you're not going to need. I use a third party program called Super Purge that has the option of purging any layer. The only drawback is that once it's purged, it's gone forever. As far as the defpoint layer is concerned, it's not a "default layer" technically. It's only created when the dimension command is invoked. It goes back to the DOS years.
Good luck with your ACAD learning. It can be both interesting and frustrating! If you have questions, post them on this site. This forum is full of helpful and knowledgeable people who've gone through the same problems you're going to have.
Depending on the situation, this is what I do:
1. Using the layer manager, I make sure that all of the layers are unlocked, thawed, turned on, not frozen in current viewport. Now you can see everything.
2. In model space, use zoom extents. If the drawing zooms and you can't see any objects that would cause this to happen, there might be some very little objects like points or extremely small text somewhere. If so, use the erase command and window in the empty areas around the main part of the drawing to see if anything gets highlighted, and erase them.
3. Delete all layout tabs (except model) to get rid of any title blocks or unwanted trash in paper space (if applicable).
4. Do my first purge to get rid of all unused objects (blocks, layers, etc.). With large drawings, this helps to free up memory and speed things up. Depending on your system, if a drawing is real big, it slows down AutoCAD on things like regen, pan, etc. Also, when you purge, make sure your layer is set so that you know there are few or no objects on that layer, like layer 0.
5. Type xref to see if there are any xref’s attached. I detach any xref’s that are not found or unloaded. If there is an xref attached and loaded and I want to keep it, I will select it and use the “Bind” button, then select “insert”. This will permanently insert the xref into that DWG as if you did it with the regular insert command. Now you have total control over its properties. Now there should not be any xref’s in the drawing.
6. Purge again to narrow down the process and help speed things up.
7. I use the express tools “Layer iso” to start isolating layers that I want to delete. Then turn back on all of the layers. It’s not a good idea to select a lot of different layers at one time - this way you can look and make sure there is nothing on that layer you need. After deleting a few layers, purge again and see if they are gone. If not, there is something using that layer, like a block. If you don’t want to retain any blocks, explode the whole drawing. You might have to repeat the explode command several times or even do a section at a time to make sure you get everything. If you don’t have express tools, get them - there are a lot of neat tools in there.
8. When I finally get most of the unwanted stuff out of the way so I can see exactly what I want, I isolate those layers and copy them way off to the side. Then turn back on all layers and delete the original area and purge. Then zoom extents and the copy you made should be center screen.
9. Now you should only have the layers of the copy you made. At this point, depending on what I want, I’ll change whatever is left to one layer and purge.
10. Save the purged drawing for reference. Use cut and paste to bring the object into the drawing you want. This way you don’t run the risk of bringing over any other stuff you could not get rid of.
This process works for me most of the time, and I’m sure as time goes on, you will develop different ways to do this. Just remember to share.