Suddenly, I can't draw construction lines. If I open a new drawing I can, but this one suddenly stopped letting me draw them.

Can you draw other things normally?  It is possible for the current Layer to be turned off, or for the current entity color to be the same as the background color, but if either of those is the reason, you wouldn't see anything else that you draw, either (in some commands you'll see the object during the construction of it, but it will disappear once the command is completed). If that's not the issue, is it just XLINEs?  Also RAYs [the one-ended form of Construction lines]?  Anything else you can identify?

It's the Draw Construction Lines command AMCONSTLINES. It creates a new layer and has a feature where you can delete all of them at once, etc. The other commands work fine. I was using it in the beginning of the project, now it won't work at all. I have even re-installed AutoCAD since the problem began due to other issues. Still doesn't work. It's that drawing only.

It brings up the dialog box, lets me select a function, but when I go to place the line there's nothing.
cavemaned2019-02-08 19:27:59

[QUOTE=cavemaned]It's the Draw Construction Lines command AMCONSTLINES. ....[/QUOTE]That's not a base AutoCAD command.  From the AM part I assume you're using AutoCAD Mechanical.  If so, I can't help you, but can you re-install that part, not just the underlying AutoCAD [if that's even how it works....]?