AEC Standards - .stb, .ctb, lineweight by layer?

[ROBinHI]

Hi,

We were tasked to setup some CAD standards to follow the AEC CAD Standards. It looks as though the lineweights are assigned to each layer. Does this mean lineweights assigned to layers do not use a .ctb file for plotting? We went ahead and setup all our layering to plot to the line thickness stated in the AEC standards.

My questions are:
1.) With layers lineweights set to a thickness, does a .ctb file still need to be selected to print? The option to select one is still available.
2.) Because the option is still available, what takes priority when layers have a lineweight set and a .ctb file is selected?

Another thing that I am curious about is in the past we've received .dwgs that use .stb for printing. I've never really understood what the purpose of an .stb file was? All I knew was that when plotting, my .ctb files were not available for selection. When I receive a drawing that was set to print in .stb, I've always converted back to .ctb using (convertpstyles). The plot styles would then become available and I would select the .ctb file to use. What are the reason, or maybe the what I should be asking is what are the benefits and drawbacks of using .ctb vs .stb?

Can someone explain how and when you would use each of these lineweight control methods? 1.) Layers configured with lineweights 2.) Plotting with .ctb 3.) Plotting with .stb

Thanks in advance!

[reikajapan]

Can someone explain how and when you would use each of these lineweight control methods?
1.) Layers configured with lineweights
2.) Plotting with .ctb
3.) Plotting with .stb

1.) Some places use this to avoid having an incorrect ctb or stb used, the file will plot the lineweights intended. This is not so great if the drawing(s) are xrefed into other drawings since you can't control the lineweight quickly with ctb or stb, but it can still be changed in the layer manager. I haven't ever worked this way so there may be more to it than I am describing.

2) Since this is still used by most places changing to stb doesn't make sense in a lot of situations. CTB is a pen color equals a pen width method. Color_7 may be set to .30mm, Color_142 may be set to BW 50%. Not the most intuitive setup as every firm will use a different color for different pen widths, but we have used it for a long time and our brain gets used to translating the information on screen. Typically you end up with lots of CTB files with this method. With CTB's you have 255 (256?) styles to keep track of and memorize what they produce.

3) To put it simply STB allows you to use any color you want for the layer and a named plot style controls the width of the line plotted. You might have a plot style name of BW.30 which is set to plot to .30mm, BW50% set to plot to BW 50%. You could have 10 layers using that plot style name and each layer could have a different color. If you realize a layer should plot to .25mm you change the plotstyle name associated with that layer rather than the color of the layer. You can end up with one or two STB files to cover everything needed for any file. With an STB you might have 10 to 20 style names. I plot in color or a mixture of BW and color so I prefer STB.

End of the day I can work with either one but I prefer STB.

[Opie]

This article explains usage of .STB files very well.

[dgorsman]

In short STB works exactly the same as CTB. The only difference is that instead of a fixed list of plot styles in CTB (ACI color numbers) you have a variable list of plot style names in STB.

As for assigning line widths to a layer (with objects as BYLAYER), that has a number of effects. For starters when printing you will *always* have a plot style table (CTB or STB) - its not optional. How the drawing plots will still be determined by the plot style table. The line widths assigned to layers are only in play if the plot style has "Object lineweight" selected. We have some drawings which work this way, and we exploit the settings to get both full size plots and reduced size plots. For full size, our CTB has "Object lineweight" selected so the printed lineweight is determined by the layer setting. For reduced plots thats way to thick, so the CTB has an assigned (thinner) lineweight for each color instead. We could use the "Scale lineweights" setting, but the differences between thick and thin lines becomes so small you can't easily tell them apart.

[tedg]

Hi,
My questions are:
1.) With layers lineweights set to a thickness, does a .ctb file still need to be selected to print? The option to select one is still available.
2.) Because the option is still available, what takes priority when layers have a lineweight set and a .ctb file is selected?

To add to this, a CTB file can be set up to use "object line weights" instead of color-assigned line-weights, which means the assigned layer line-weight (or if an object has a line-weight assigned to it other than ByLayer..which is evil in my book).

NCS 4.0 (CTB) introduced this, where all colors are printed black and uses object line weights as I stated above, except the 250-255 prints the actual colors and some have screening.

[ROBinHI]

Thanks for clearing some of this up guys. What are most firms using now? We've always used .ctb. Is it easy enough to switch back and forth between the two or does switching mean that each and every drawing needs to be converted to use ctb or stb? I'm trying to determine if we have to decide on one to use or if it can easily be interchanged between these several methods.

[ROBinHI]

One more question. How does this affect working with drawings from other sources (clients, consultants, etc)? Say if they use .ctb or their layer standard is totally different than ours. Would we have to switch up to match ctb/stb plotstyles on their drawing files for printing? I'm assuming we'd have to package our stb file along with our drawings and inform them of what we're using with instructions in case they have never used stb? Majority of the firms we deal with still use ctb, I believe?

Can you assign stb plotstyles to an xref from a host file where the reference is inserted? or must the plotstyle be set in the xref itself?

[jaberwok]

Each drawing file "knows" it requires an stb or ctb file. See CONVERTPSTYLES and CONVERTCTB commands.
If you use etransmit when sending drawings out, your stb/ctb file will be included in the zip file (along with anything else your drawing references.
You will want your other sources to use etransmit also.

[tedg]

Thanks for clearing some of this up guys. What are most firms using now? We've always used .ctb. Is it easy enough to switch back and forth between the two or does switching mean that each and every drawing needs to be converted to use ctb or stb? I'm trying to determine if we have to decide on one to use or if it can easily be interchanged between these several methods.

We've always used CTB files, at least that is my company/office standard.
We have used STB files when imposed upon us, it takes a little getting used to at first, not to bad though.

As Jaberwok mentions, the AutoCAD file knows which one a file has been set up for, it's either one or the other.

An added note going back to my last post, our layer templates have colors and lineweights assigned to them.

So if we're using a ctb file that uses object line weights such as NCS 4.0 or even OOTB Acad.ctb, the lineweights are there (for acad.ctb we change the colors to white/gray at the sheet level for plotting).

If we need color based ctb plotting, our color scheme is NCS 3.1 (for NCS 3.1 ctb) which closely follows NAVFAC, and other NCS-friendly standards.
And we can always sort the layers by lineweight, and assign colors for lineweights that match up to a specific ctb file.

[Tom Beauford]

I use Autodesk-MONO.stb installed with AutoCAD and standard Windows True Type fonts, mostly Swis721 Lt BT. Anyone who gets one of my drawings should have no problem plotting them.