Whats the use of CTB
I use the pen weights assigned to the layers then as Totalsurv says I have a CTB file which plots the first 7 colors black. So I can use any of the first 7 colors I want for on-screen viewing purposes and it will still plot black per the lineweight assigned to the layer.
The ability to set lineweights came in, what, 20 years ago? Yet most are still plotting a given lineweight by color which I find aggravating. What color is a 0.7mm lineweight again? The one that looks like light pink chartruese. what?
CTB files came from back in the day of pen plotters when say red would plot to pen 1 and yellow to pen 2, etc.
CTB is a color table used by AutoCAD. The different colors represent the line thickness. If using C3d 2015 or newer, you can plot by STB (style table) which color doesn't matter, if you want thicker lines then the user changes the lineweight.
I use an stb (style based) so that line weight is primarily controlled by layer. If I want a layer or object to be in color I set the style to "normal", "style1" gets me solid black lines with the weight by layer, and "style2" is set to give me 50% screening with the line weight still controlled by the layers.
@squirl Not throwing rocks, but I started with AutoCAD 13 on Windows 95 and it had STB.......most folks just didn't use it. Oddly, I think vanilla AutoCAD still defaults to CTB out of the box if you use their drawing templates.
After about 30 years a work flow becomes very natural. If you started with CTB you probably still use it. Not a hard and fast rule but very common. We are creatures of habit and rarely change course without good cause. Even then it may not happen..