topic Betreff: AutoCAD - What is the point of a CTB file? in AutoCAD Forum

AutoCAD - What is the point of a CTB file?

fkuznets — Fri, 28 Oct 2022 08:27:32 GMT

I'm new to AutoCAD, so sorry if this is a bit of a silly question, but aren't CTB files redundant? Why would I ever need to use them? From what I understand, they're just a way to assign a bunch of properties to things in my drawing, but couldn't I just do that using layer properties?

[ The subject line of this post has been edited for clarity by @handjonathan Original: What is the point if a CTB file? ]

Betreff: What is the point if a CTB file?

illusionistNUGXG — Fri, 28 Oct 2022 06:18:12 GMT

It is harder to work with drawings, if all everything is set in the layer properties. All lines look alike.

I can differentiate line styles with ease.

(i use a dark background) white lines = wide

green = thin

magenta = thin, dashed

cyan = middle lines (dash + dot)

...and they all print black

Also different ctb files can change the printed (or PDF) outcome with one selection.

e.g. thinner lines overall, or monochrome.ctb for black/white only

Re: What is the point if a CTB file?

imadHabash — Fri, 28 Oct 2022 07:50:55 GMT

Hi and Welcome to AutoCAD Forum,

CTB, or color-dependent, plot styles are settings for how the 256 available colors in AutoCAD will appear when you plot them, including the lineweight assigned to each color. When you use CTB styles, you are essentially adapting some or all of the colors 0 through 255 to meet your office standards for plotting. You can use Color Plot Styles to plot in black and white or color.

By using a finite list of layer colors, CTB styles make it easier to tell which layer is which in your drawing and makes it easier to rescale for plotting.
The CTB file offers myriad options, but you are primarily concerned with three:
- The color in which the source color should plot
- Line thickness
- Screening

Re: AutoCAD - What is the point of a CTB file?

RSomppi — Fri, 28 Oct 2022 13:58:32 GMT

@fkuznets wrote:
aren't CTB files redundant? Why would I ever need to use them? From what I understand, they're just a way to assign a bunch of properties to things in my drawing, but couldn't I just do that using layer properties?

It's not really a redundancy but rather a choice for you to make.

Re: AutoCAD - What is the point of a CTB file?

rkmcswain — Fri, 28 Oct 2022 14:12:03 GMT

@fkuznets wrote:

.... but aren't CTB files redundant? Why would I ever need to use them? From what I understand, they're just a way to assign a bunch of properties to things in my drawing, but couldn't I just do that using layer properties?

Prior to ~2004 (not sure of exact release), there were no "lineweights" in AutoCAD. So in order to have objects with various widths, we had to use plot styles, or use polylines with a width (and not all objects can be represented with polylines).

Many, dare I say most, people and firms who learned this way still do it this way. As said above, it's a choice.

Re: AutoCAD - What is the point of a CTB file?

Ed__Jobe — Fri, 28 Oct 2022 14:50:42 GMT

@rkmcswain wrote:

@fkuznets wrote:

.... but aren't CTB files redundant? Why would I ever need to use them? From what I understand, they're just a way to assign a bunch of properties to things in my drawing, but couldn't I just do that using layer properties?

Prior to ~2004 (not sure of exact release), there were no "lineweights" in AutoCAD. So in order to have objects with various widths, we had to use plot styles, or use polylines with a width (and not all objects can be represented with polylines).

Many, dare I say most, people and firms who learned this way still do it this way. As said above, it's a choice.

@fkuznets In addition to what RK mentioned, layers are more for controlling screen appearance, whereas ctp (and also stb) are for controlling plot output. For example, our standard plot size is Arch D. We have a ctb that specifies the lineweights and maps all the layer colors to black. But for a check print (Arch B) we use a ctb that scales the lineweights by half. If all you had were layers, you would have to change the layer settings to get a different plot.

Re: AutoCAD - What is the point of a CTB file?

RSomppi — Fri, 28 Oct 2022 14:55:46 GMT

@Ed__Jobe wrote:
If all you had were layers, you would have to change the layer settings to get a different plot.

Are you sure?

Re: AutoCAD - What is the point of a CTB file?

Ed__Jobe — Fri, 28 Oct 2022 15:02:17 GMT

@RSomppi wrote:

@Ed__Jobe wrote:
If all you had were layers, you would have to change the layer settings to get a different plot.

Are you sure?

Good catch. oops.

Re: AutoCAD - What is the point of a CTB file?

payingtoomuch — Sat, 29 Oct 2022 15:54:48 GMT

I'm interested in this too. Have been drawing in autocad for 20 years+ and have only dabbled in making a switch to by layer assignments of lineweights, linetypes, transparency & color.

One of the posts above seems to indicate that there is no way to still see color of the lines in model space when working.... but this doesn't seem to be accurate. Question would be that if "none" plot style is selected and line color is assigned by layer if there is a way to still have it plot black (or grey) and ideally when a layout tab is opened, be able to see the color that the line will be plotted at. Thinking this might require changing the vp layer color to black (or gray) for each individual linetype? That could get cumbersome. Not sure that path to take but I do like some of what I'm thinking through on the switch from ctb to assignments by layer.

Re: AutoCAD - What is the point of a CTB file?

Ed__Jobe — Sat, 29 Oct 2022 16:56:49 GMT

@payingtoomuch wrote:

One of the posts above seems to indicate that there is no way to still see color of the lines in model space when working....

I didn't see that indicated anywhere. Layers have both color and lineweight settings, just like a ctb file has. If you choose "none" for the ctb setting in page setup, then the plot uses the layer settings (and object if it overrides the layer setting). The ctb is just a way to store overrides and easily switch back and forth. Layouts can't completely display what a plot would look like, although you can display lineweights. For that you need to use plot preview. If you want to plot all black, just use the acad-supplied monochrome.ctb.

Re: AutoCAD - What is the point of a CTB file?

payingtoomuch — Sat, 29 Oct 2022 17:12:56 GMT

Not meaning to hijack the thread....

Below is where I got the notion that someone was thinking they couldn't see color in model space if they chose to set up drawings with color by layer....

"It is harder to work with drawings, if all everything is set in the layer properties. All lines look alike.

I can differentiate line styles with ease.

(i use a dark background) white lines = wide

green = thin

magenta = thin, dashed

cyan = middle lines (dash + dot)

...and they all print black"

Was trying to get away from ctb.... but already having issues heading that direction.

-1st issue appears to be that because the default lineweight- assigned by "lwdefault" (which would be the majority of my lineweights "assigned" to the various layers) is apparently a global setting (all drawings would revert to any new setting). So, if anyone arbitrarily selects some obscure lineweight then their (and my drawings) will not plot properly.

- Also. Thinking will be way more cumbersome having to select black or grey for all the various layers in the viewport everytime a new viewport is created and/or a new layer is created.

Think I'm bailing already. Can anyone convince me to stay the course and and get away from plot styles?

Re: AutoCAD - What is the point of a CTB file?

Ed__Jobe — Sat, 29 Oct 2022 17:27:10 GMT

It depends on your needs, only you would know what works best for you (or your company). But you may want to look at named style table files (stb). Most use color tables because they just never changed from the way that AutoCAD first introduced...too hard to make a change, etc. But named styles have advantages too.

Re: AutoCAD - What is the point of a CTB file?

payingtoomuch — Sat, 29 Oct 2022 18:07:14 GMT

Thanks Ed. I played around with STBs some years back and got away from it for some reason..... Will look again.

Re: AutoCAD - What is the point of a CTB file?

payingtoomuch — Sat, 29 Oct 2022 18:10:10 GMT

Very quick search revealed...

"If you want to be able to set your lineweights completely independent of the color of things on your screen, the stb is the way to go"

Definitely need to look into them again because after all said and done, this is probably the big reason I'm looking to make a change.

Thanks.

Re: AutoCAD - What is the point of a CTB file?

dngow — Fri, 07 Feb 2025 22:54:17 GMT

@payingtoomuch wrote:

- Also. Thinking will be way more cumbersome having to select black or grey for all the various layers in the viewport everytime a new viewport is created and/or a new layer is created.

Civil 3D 2025 here. This is what originally did it for me... that a new viewport would require the cumbersome work for all the layers, but if I have an existing viewport and I create a new viewport, it inherits all of the layer states from the first viewport. Additionally, layer properties now has a layer states manager that can save your settings so you can load it for another viewport. It's like a ctb file, but for viewports.

I receive drawings where layer names can change, be typo'd, etc, but I also can't rely on the color or name being the same every drawing... yet. That makes ctb and stb files less useful for me. Layer states hasn't been helpful so far either since new viewports are inheriting the layer states anyways since all of my viewports have the same settings. (maybe if you have multiple viewports all with different layer states, I see the Layer state manager being very useful). So making a template drawing is how I'm doing it. It is painful, but at least I only do it the once. The drawings I receive to process though, I don't see an easy way of dealing with that, but when dealt with, I know what it will all plot as. Suggestions welcome.

Re: AutoCAD - What is the point of a CTB file?

TomBeauford — Sat, 08 Feb 2025 06:02:19 GMT

I was taught the KISS principal (Keep It Simple Stupid) in the Army back in 1975 and have lived with it ever since. For the last 26 versions of AutoCAD we've been able to control lineweights with layer properties easily managed with layer states. To use plot styles to control lineweights requires multiplying the number of plot styles you actually need by the number of different lineweights you might possibly use and every user would have to understand all them which is the opposite of keeping something simple. We use an STB with only six plot styles Color, Black, 3 Grayscales and a last one that plots as a light shade which works great for solid hatching with various colors. Simple, works with millions of colors, and provides many times the options a CBT file with 256 plot styles can.

Re: AutoCAD - What is the point of a CTB file?

RSomppi — Sun, 09 Feb 2025 20:03:43 GMT

@TomBeauford wrote:
To use plot styles to control lineweights requires multiplying the number of plot styles you actually need by the number of different lineweights you might possibly use

Nope, pretty sure that's not a requirement.

Re: AutoCAD - What is the point of a CTB file?

TomBeauford — Mon, 10 Feb 2025 06:40:24 GMT

If you know some way of making CTB plot styles to control 15 colors (of the only 256 that actually work with CTBs) & grayscales for 5 different lineweights without needing 75 (15×5) different plot styles please share.

Re: AutoCAD - What is the point of a CTB file?

RSomppi — Mon, 10 Feb 2025 11:45:08 GMT

Yeah, if I'm understanding you correctly, you only need one CTB.

Re: AutoCAD - What is the point of a CTB file?

pkolarik — Mon, 10 Feb 2025 14:17:31 GMT

We have two ctb files for our printing needs. Just two (the second one is for half-sized plotting, as some plotters/printers don't handle some of the thinner and shaded lineweights correctly if we just tick the "scale lineweights" button). The 255 colors available to use are more than sufficient for managing the roughly 8 solid lineweights and 5 shaded lineweights that all our drawings require.