CTB or STB plot styles

[Anonymous]

hello fellow cad users I've been searching online for the differences between CTB and STB plot styles,

in each thread I read it seems like the answers they give are packed full of BS and then the bulling starts,  can somebody please in a kind and professional manner describe the differences in these two styles and why somebody might consider using one or the other. or should you only use these files for certain drawings?

also please try to use easy to understand language, with terms that I or somebody else wont have to google to understand. we are not all 100% experts here

thank you for your time and response

[pendean · Accepted solution]

CTB: relies on object's color to determine which pen setting is used. Simplest method out there for a newbie

STB: you have to deliberately assign each object/layer a specific pen to achieve the same output. Preferred by highly organized cad "shops"and users.

neither one is right or wrong, both are here to stay in AutoCAD as far as I know.

[pkolarik · Accepted solution]

The simplest explanation is this:

If you want to be able to open any dwg and instantly know what lines/objects are plotting at what lineweight simply by looking at the colors on your screen, ctb is the way to go.

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.

We have both in our office. Civil3d users are using stb and everyone else (we do all disciplines in-house) are using ctb.

CTB is by far the most preferred method in our office, the C3d users only having gone over to stb usage because the DOT requires it. (and yes Dean, we are a "highly organized" office)

[Anonymous]

awesome thank you!

[Anonymous]

very helpful thank you very much.

[dbroad]

The tone of your OP is unnecessarily negative but this is my take. I hope you don't consider it rambling or BS.

1. With STB (which AutoCAD has provided several tables out of the box and therefore there is no need to develop them for ACAD or ACA), there are several choices for plot style strategies. Each OOTB STB file has only a few plot styles(when compared to 256 color CTB setups) so deciding which one to use for each object or layer should be relatively easy .  For example, within the Aec Standard Color.stb, the available plot style names are: Normal, ByLayer, ByBlock, Invisible Ink, Full Saturation, 50 Percent, 25 Percent, and Standard(6 plot styles).  Although the difference between Normal and Standard takes a little while to understand, the rest aren't too difficult.  Normal cannot be modified and Standard can.  FS, 50%, and 25% plot black (solid or screened).  The rest plot in the color defined by the object or by the layer.  Lineweights are all deferred. Invisible ink just doesn't plot. The Aec Standard Color.stb table also has Normal and Standard, but each plot style sets lineweights according to standards and uses descriptive names such as Fine, Thin, Medium, Wide, Extra Wide, etc along with Thin Screened, Medium Screened, etc (18 plot styles). It doesn't have invisible ink so you would need to put things that you don't want to plot on non-plotting layers. AutoCAD Architectue presets a template to use the AEC Standard.stb so trasitioning to using it from CTB plotting requires virtually no effort except for converting legacy drawings from CTB to STB. If you have a large library of CTB content, you might as well stick to CTB.
2. CTB drawings use CTB plot styles which are set by color number and relate colors to plot styles.  There are 256 plot styles for each CTB file.  This is generally more complicated to set up, even with OOTB CTB tables, and to learn but once you learn it/them, you don't need to think about it much and standard CTB files provided by Autodesk provide for great flexibility. Older Autodesk CTB files [ie AIA(256) Scale 48.ctb] established standard lineweight to color mappings according to National CAD standards. Newer CTB files[ie  AIA LWT by Object.ctb] let objects/layers control their own lineweight.

Once you decide which way to go, you probably want to continue.  When I started CTB files were the only way to go so I learned how to use them and have a vast content library dependent on color to lineweight mappings.  About 20 years ago, I switched to CTB files that don't map color to lineweight so they are like using plot styles, just more complicated because the drafter needs to know that color 31 will plot black whereas color 41 will plot in color and color 38 will plot grayscale.  That knowledge is not necessary with STB plot styles but the effort to transition can be immense even with the commands Autocad provides to transition so I don't recommend transitioning existing files.

There is no right or wrong choice. If I was starting today, I would be using STB plot styles. If you use OOTB plot styles, I recommend not modifying them though. Otherwise teamwork suffers. I also recommend using standard OOTB CTB files if you go that way rather than rolling your own.

[Anonymous]

Very well and simply delivered explanation; just what the 'doctor' ordered.

[HJiang85U97]

ctb can be configured with lineweights not depending on colors. Just set lineweight to "Use object lineweight" for each color.

[kkuecker26]

Exactly!  Using "Use object lineweight" makes the ctb act like an stb.  

Our CTB is set to "Use object lineweight",  Which is why I never noticed it as a problem.  I don't like color dependent plot styles.  We have too many exceptions in drafting to be restricted to that.  I was using a plot style from our local DOT, and just modified things as we need for our company.  I never put much thought into until today, when our new hire said he was going to recreate the templet to not be CTB.  However, our CTB is set to "Use object lineweight".  So... why change it????

Well... at least I understand it now.

[kristiL539J]

THE SAME COLOR will BE USED WITH DIFFERENT LINE THICKNESSES. SHOULD I MAKE AN .STB FILE INSTEAD.
For example Layers:
la name color linewieght
1 red .01
2 red .5
3 red default
OOPS Sorry Cap lock was on! The current Designer here at work has layers that have different line thicknesses but they are the same color.

[kristiL539J]

la name............color.........linetype..............lineweight............

1..........................red...........continuous...............5...............

2...........................red...........continuous.............0125........

3...........................red............dashed.....................13..........

[David_W_Koch]

@kristiL539J 

DISCLAIMER:  I have no knowledge of the way your office works.  Any of the suggestions below may be at odds with your typical workflows, or may solve one problem but create three more.

The plot style file (CTB or STB) does not have to set the lineweight.  The lineweight for Color 1 could be set to Use object lineweight in the CTB file and then the resolved lineweight in drawing would be used.

The colors in the drawing could be changed to work with a plot style file you already have set up.

If the colors have to stay as they are (because, designers...) and lineweights have to be assigned in the plot style file (because you plot the same stuff with two or more different plot style files to get different effects, and the lineweight varies from one effect to another), then you may need to set up a named plot style file (STB) so that the three reds all plot as desired. 

Assuming that the current drawing uses color-dependent plot styles (CTB), you will need to:

• Convert your CTB file to a mapping STB file for use in the conversion with the CONVERTCTB command.
• Convert the drawing file from CTB to STB using the CONVERTPSTYLES command, using the mapping STB file previously created.
• Set the new STB file you created as the current plot style file in the STB drawing file.
• Assign the desired named plot styles in the STB drawing file.  At the least, assign the correct plot style to your Layers.  If you have objects that had hard-coded Colors - colors not set to ByLayer or ByBlock - then you may need to assign plot styles directly to those objects (rather than the preferred ByLayer or, for nested objects, ByBlock).  Otherwise, if you have a red object on a green layer, and you assign the equivalent of your green plot style to the layer, the object will plot like it was green, not red.

[Gambit80]

Quick question. Do you then have specific pens for shaded linework? How do you handle hatches that need specific shading.

I am sure I am overthinking this as I vet moving either from full CTB to CTB with object LW or STB.

Thank you

[rwrightWMDSY]

In your .CTB pen definition file you are able to set a degree of screening for any given color.  Setting Screening to anything other than 100 will give you a half-tone (faded) line.  It takes a bit of trial and error to get the combination of lineweight and screening you want.  As an example:  We use color 231 for a fairly light background poche.  The line weight is set to 0.4000mm and the shading level is set to 40 and (most of the time) it's used for a solid fill hatch pattern.  

[David_W_Koch]

@Gambit80 

Also note that all that @rwrightWMDSY stated also applies to "pens" in an STB (named) plot style file.  The available pen properties are the same in both types, the difference is in how they are assigned - by object color or by direct assignment.

[Joe-Bouza]

I know this is an ancient post. I came across it for similar reasons. Sometime along the acad journey changed. ctb files can be set to plot object lineweight. 

you can force the weight or use the object / layer defined lineweight

is this different than stb?

[David_W_Koch]

@Joe-Bouza 

No, the settings for CTB and STB files are the same.  The only difference is that in an STB file you create your own name for each plot style; in a CTB file the plot style name is fixed, and based on one of the standard AutoCAD object colors (1 through 255).

[Joe-Bouza]

Hi @David_W_Koch , thanks for replying

but I am still confused. 

"The only difference is that in an STB file you create your own name for each plot style" sorry but I don't understand this statement.

[David_W_Koch]

@Joe-Bouza 

Here is a side-by-side comparison, which may make things clearer.

The properties available to be set on a plot style are identical for both CTB and STB.  The difference is in the naming of and number of plot styles. 

• A CTB file always has 255 plot styles, one for each AutoCAD index color (Color 1, Color 2, Color 3, ..., Color 254, Color 255).  Those names are fixed; you cannot change them.  You cannot add more plot styles or remove plot styles you are not using.
• An STB file will always have at least one plot style, called Normal, which cannot be deleted; its properties are also fixed.  This gives the program a known plot style that can be assigned as a default when a plot style has not been selected.  All of the other plot styles are user-created and user-named, and can be deleted or renamed at will.

The main functional difference is in how they are assigned.  In a CTB drawing, the resolved object color determines the plot style that is assigned (if it resolves to an AutoCAD index color, anyway).  In an STB drawing, plot style is another object property that can be assigned an explicit plot style or be set to ByLayer or ByBlock.  Outside of ACA Display System settings, my firm typically sets main objects to ByLayer and allows the plot style set on the layer to control the effective plot style.  For complex objects (mostly block references), the nested objects that are to inherit the parent object plot style are placed on Layer 0 with plot style set to ByBlock.  In some situations, the nested objects are placed on a specific layer, with plot style set to ByLayer, so that they inherit the plot style assigned to the specific layer.

[Joe-Bouza]

Wow! 30 years and such a simple picture finally drove it home. So with an stb you can assign multiple plot style to multiple objects through the single stb.

Thank you David.

Thanks for taking the time