Overriding CTB Plot Styles

Overriding CTB Plot Styles

Have you found that polylines, text or other objects always tend to print in black or gray? It may seem that no matter how many times you change the properties, the color never seems to take hold. For those of you who prefer to add a bit of color into your Civil 3D drawings, this post will walk you through a few simple steps to override the CTB file and force your individual objects and layers to print in color. This method is useful when illustrating or highlighting important notes, objects or boundaries such as a proposed waterline.

But first a bit of background…

All Civil 3D objects are assigned a color. This characteristic is set either by layer, block, or user-defined properties. Every color is made up of a certain combination of red, green and blue – or RGB. Each color level has a range of 0 (least vibrant) to 255 (most vibrant). Different combinations of RGB levels will blend to make a new color – as you would if painting. To make life easier, Civil 3D is set up with 255 preset index colors – each with a different RGB combination.

A CTB file assigns each of these index colors a set of “plot style” override properties (e.g. color, screening/transparency, linetype, lineweight) that define how an object will display once printed on paper. At this point, all Maryland NRCS templates utilize the NRCS BWgray.ctb file. To access CTB files, enter “STYLESMANAGER” into the command line and press “Enter”.

Through the NRCS BWgray style, each index color is assigned a certain black or gray plot color. Note that many of the actual gray and black index colors will be set to “Use object color” since they are already grays and blacks respectively. The only other exception is Color 240; this index color will plot as red and is meant for all as-built details and redlining. All linetypes and lineweights are set by layer or object-property overrides.

Another point of note is that the Maryland templates are also set to automatically display plot styles in Paper space. In other words – layouts in Paper will (by default) show as they would as if they were printed out on paper. This is why an object will display the index color in Model yet will show as black or gray in Paper. This option can be turned off/on in the Page Setup Manager. It is important to remember that changes here are strictly visual – the drawing file will still print according to the plot style settings.

To force object color… 

Users can force an individual object or layer to print in actual color after manually assigning a RGB combination differing from one of the predefined index colors.

Before proceeding – ensure that the Display plot styles option (as described above) is turned on. This allows users to verify that the following steps are in fact working.

Next, find and select the object in Model. Right-click the object and open Properties.

In the Properties window, expand the Color drop-down menu and click Select Color.

Select an index color close to the color that you would like to plot. Reminder: this index color will print as black or gray if left as is. Do not stop at this step.

Click the True Color tab. Drag the R, G, B sliders to achieve a color that is similar to yet does not directly match the index color settings. Click OK.

Return to Paper and verify that the color is now activated.

 

In summary…

Civil 3D utilizes 255 preset index colors made up of a specific combination of red, green and blue. A CTB plot style assigns a printed color override to each preset index color. If the user manually defines a red, green, blue combination that differs from the 255 index colors, that user-defined color will print as defined and shown in Model.

-JD

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