@Mayra.Moyles wrote:
Why can't I create a layer in the middle of a command that requires a particular layer to exist?
....
You can. Type in 'LAYER [or just 'LA if you haven't changed the default alias] with the apostrophe prefix. That brings up the Layer Manager, where you can do what you need, and when done, returns you to the command in progress. Or if you want to do it at the command line instead of the Layer Manager, use '-LAYER [or '-LA], with the apostrophe and hyphen prefixes.
That's called "transparent" use of the command, and a variety of commands can be used that way. See "Interrupt a Command with Another Command or System Variable," >here<.
@Mayra.Moyles wrote:
this is what I saw when I tried the apostrophe use.
Enter new layer name <A-Rack>: pequip
Cannot find layer "pequip".
Enter new layer name <A-Rack>: 'layer
Cannot find layer "'layer".
Which Layer option are you in at that point? If it's Set, it will give you that message if the Layer doesn't exist, but I doubt it -- the prompt would be different. I'm not getting exactly that prompt in either the Make or New options, either [maybe version differences? Acad2020 where I am now]. Show us the broader context of prompts for the "outer" command you're in, where you are in its sequence, and exactly how you get into 'LAYER from there. In case you might have an override-defined Layer command, try .-'LA with the period prefix, to force use of the native command.
@Kent1Cooper wrote:
.... I'm not getting exactly that prompt in either the Make or New options, either ....
That must be because I think you are in the LAyer option in the CHPROP command [or under the Properties option in the CHANGE command], not in the 'LAYER command yet. It seems since the prefix characters are all acceptable as parts of Layer names, this can't be done at that point in the process. It works earlier in the command, such as at the which-Property-do-you-want-to-set prompt. I even tried setting TEXTEVAL so that AutoLisp expressions should be evaluated rather than taken literally, and put in (command "_.'layer") there, but since parentheses are also acceptable as parts of Layer names, that didn't work either. I'm not sure whether there's a way around that, but if you can do the 'Layer part before getting as far as into the LAyer option in CHRPOP, you can still do it.
@Mayra.Moyles wrote:
....it would be very helpfull if Autocad instead of telling me "cannot find layer.." it would say, "cannot find layer, would you like to make new layer (y/n)? " ....
There is one circumstance that kinda-sorta works in a similar way, in the sense of just creating the Layer if it doesn't already exist, without the use of a Layer command or (vla-add...) methods or anything, though it won't help you with the current topic unless you want to do your Layer changing through AutoLisp rather than CHANGE/CHPROP.
If you pull the entity data list for an object in AutoLisp, and you go to change its Layer by (subst)ituting or (append)ing an entry for the Layer [the DXF code 8 entry], the Layer name you include there will be used, whether or not the Layer exists. If it doesn't exist, it will be created in the process, using default continuous linetype and color 7 used for new Layers.
