It may seem like a great idea to use the layer “DEFPOINTS” as the layer for your viewports since it doesn’t plot by default. And you may have heard from various posts that you shouldn’t do so but may have not understood why…
It has to do with both Layer 0 (zero) and Defpoints.
Note: I am using “Layer 0 (zero)” because I dont want the zero to be confused as the capital letter O.
Layer zero is reserved for objects like blocks so if they are set to layer zero and you insert them into a drawing, the current layer could be set to anything, and that block will now be on that layer. So CAD managers might have Layer 0 (zero) turned off or even frozen so that people don’t use this layer to draw objects that should be on a designated layer.
If layer 0 (zero) is not turned off or frozen, you can select everything as normal (shown below
Let’s say that you Freeze Layer 0 (zero) [shown below]
Now try to select the same layers that were select-able prior to Layer 0 (zero) being frozen. You will notice that you cant select the objects that are on the DEFPOINTS layer. It’s like some sort of force field has been applied to these objects…
So how will this cause issues?
If your viewports are on the DEFPOINTS layer, and you want to later come and change the scale of the viewport, you will not be able to select the viewport. However, you can still double click inside the viewport to adjust the scale but some people use DEFPOINTS for placing other objects that they don’t want to plot like text that serve as notes or whatever. If they later what to erase them or move them or edit them, they wont be able to do so.