Guide

AutoCAD Plot Style : A setting that controls the appearance of objects when printed

This guide explains plot styles in AutoCAD in clear, step-by-step terms for beginners. You will learn what plot styles are, why and when to use them, how to create and edit them, alternative methods for controlling printed output, common errors and fixes, practical tips, and a helpful FAQ.

What is a plot style?

A plot style in AutoCAD is a set of rules that controls the appearance of objects when printed or exported to PDF, independently from how they appear on screen. Plot styles control properties such as:

  • Lineweight (thickness)
  • Screening (percent opacity)
  • Color mapping (print color or grayscale)
  • linetype scaling (sometimes via lineweight/pen assignments)
  • Whether an object plots at all (plot/no plot)

Plot styles are stored in plot style table files: two main kinds exist:

  • Color-dependent plot styles (.ctb) — map each drawing color (index color) to specific print properties (common in architectural/CAD office workflows).
  • named plot styles (.stb) — use named styles that you assign to layers or objects (flexible, often used in standards-driven environments).

Why use plot styles? Benefits and use cases

Using plot styles gives you control and consistency over printed drawings:

  • Separation of screen appearance and print appearance — keep bright colors on-screen for clarity while producing professional black-and-white prints with correct lineweights.
  • Consistent output across drawings — ensure all drawings follow office or project plotting standards by reusing the same plot style table.
  • Simplified plotting workflows — change print behavior globally by editing one plot style table rather than editing dozens of objects or layers.
  • Support for layer-based drafting standards — assign lineweights and plotting behavior per color or named style instead of per-object editing.
  • Faster revisions — adjust thickness and darkness for an entire drawing by changing the plot style, not individual entities.
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Typical use cases:

  • Architectural and civil firms using .ctb tables to map colors to pen thicknesses.
  • Engineering firms preferring .stb for named styles that map directly to standards like “Dimension”, “Hidden”, or “Centerline”.
  • Producing monochrome prints from colorful Model space drawings.

Color-dependent (.ctb) vs Named (.stb) — key differences

  • .ctb (Color-dependent): Print behavior depends on the object’s AutoCAD color number (not layer name). Quick to apply when drawings use color-by-layer consistently. Common in many CAD offices.
  • .stb (Named): You assign named plot styles to objects or layers (e.g., “Thin”, “Thick”, “NoPlot”). More explicit and portable because behavior is tied to the style name rather than color.

Which to choose?

  • Use .ctb if your office standard maps color indices to pen widths and you already color-code layers.
  • Use .stb if you want clearer, named styles and avoid relying on specific color indices.

When and how to use plot styles (overview)

Why:

  • To control print lineweights, shades, and visibility without changing the drawing content.

When:

  • Before printing or exporting to PDF.
  • When preparing archival or client-ready drawings.
  • When you need to enforce a drawing standard.

How (high-level):

  1. Open the Plot dialog (type PLOT or use Print/Plot from the application menu).
  2. Choose a printer/plotter or “DWG to PDF”.
  3. In the Plot Style Table (pen assignments) drop-down, select a .ctb or .stb file.
  4. If needed, click Edit or New to create/modify a plot style table.
  5. Assign styles (for .stb) to layers or objects via the Properties palette or layer manager.
  6. Preview and plot.

Step-by-step — Create and edit a plot style (.ctb or .stb)

Note: Menu wording may vary slightly by AutoCAD version, but the sequence is consistent.

  1. Open the drawing.
  2. Type PLOT and press Enter (or go to Application menu > Print > Plot).
  3. Confirm the desired Printer/Plotter and Paper size.
  4. Locate the Plot style table (pen assignments) dropdown:
    • To use an existing table, select it.
    • To create a new one, click New… (this launches a wizard).
  5. In the New Plot Style Table wizard:
    • Choose Start from scratch or Use existing as a template.
    • Choose Color-dependent (CTB) or Named (STB) when prompted.
    • Give the file a descriptive name (e.g., “OfficeStandard.ctb” or “A1_BW_Thick.stb”).
  6. After creating, select the new table and click Edit to open the Plot Style Table Editor.
    • For CTB: You will see the list of colors (1–255) and can assign pen width (lineweight), screening, grayscale/rgb mapping, and plot/no plot.
    • For STB: You can create named styles and define the same properties for each named style.
  7. Save the plot style table. It is stored in the Plot Styles folder for AutoCAD (so it’s available to other drawings on your system).
  8. Assign the plot styles in your drawing:
    • For CTB: ensure layers/objects use the color index that maps to the desired print behavior (e.g., Color 1 = Thick).
    • For STB: assign a named style to a layer or object by selecting the object, opening the Properties palette, and choosing the named plot style; or use the layer properties Manager to assign a named plot style to layers.
  9. Use Preview in the PLOT dialog to verify results before printing.
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Alternative methods to control print appearance

  • Layer properties: Set layer color, lineweight, and plot/no plot in the Layer Properties Manager. This works together with plot styles — be aware of which setting overrides which in your workflow.
  • Viewport overrides (layout viewports): In layouts, you can override layer properties inside a specific viewport (use the viewport layer freeze/thaw or property overrides) to vary the printed appearance per sheet.
  • Object overrides: Use the Properties palette to set lineweight or plot style for a specific object (overrides layer defaults).
  • Plot Styles + Layer combination: Many offices combine .ctb files with color-by-layer conventions for fast, standardized plotting.

Common errors and fixes

Error: Plot style not applied — preview shows unexpected lineweights or colors.

  • Fix: Confirm the drawing is using the correct plot style table in the PLOT dialog. For .ctb, check that object/layer colors match the CTB mapping. For .stb, ensure objects have the correct named plot style assigned.

Error: CTB file is missing when opening a drawing.

  • Fix: Place the CTB file in the AutoCAD Plot Styles folder or set a new plot style in PLOT dialog. If receiving drawings from others, ask them to send the CTB/STB used or convert the drawing to your plot style system.

Error: Lines plot too thin or too thick.

  • Fix: Edit the plot style table to adjust pen widths (lineweights) and re-plot. Also check printer/plotter calibration and driver settings.

Error: Objects that should be hidden are printing.

  • Fix: For layers set to “plot/no plot,” verify the layer property. For CTB, ensure the color is set to “No Plot” if you want a color not to print. For STB, set the named plot style’s “Plot” property to off.

Error: Converting between CTB and STB is confusing.

  • Fix: Choose one system for your office. AutoCAD provides tools/wizards to convert drawings from CTB to STB and vice versa — search the Plot Style conversion wizard in your AutoCAD version or use the New/Convert Plot Style Table wizard. Test conversion on a copy of the drawing first.
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Practical tips and best practices

  • Always keep a copy of your office plot style tables in a shared folder or template so team members use the same standards.
  • Name plot styles clearly (e.g., “A3_BW_0.35mm” or “Dim_Thin”) so their purpose is obvious.
  • Use Preview before printing — it saves time and paper.
  • If you inherit drawings, check whether they were created with CTB or STB and decide to convert or adopt theirs.
  • For consistent printing, set lineweights in the plot style rather than relying solely on color or screen appearance.
  • When exporting to PDF, use the same plot style table as you would for a physical plotter to maintain consistent results.
  • Add plot style tables to your project templates (.dwt) so new drawings automatically reference the correct table.
  • Keep the number of named styles reasonable and documented (a short list like “Thin, Medium, Thick, Hidden, NoPlot” often suffices).

FAQ

What is the simplest way to change lineweights for an entire drawing?

Edit the active plot style table (CTB or STB) and adjust pen/Lineweight settings. Then re-plot. This changes output globally without editing individual objects.

How can I tell if a drawing uses CTB or STB?

Open the Page Setup Manager or Plot dialog; the Plot style table dropdown will show the type (.ctb or .stb) currently assigned. Also, check whether layers/objects show named plot styles (STB) or just colors (CTB workflows).

Can I use both CTB and STB in the same AutoCAD installation?

Yes, AutoCAD supports both file types, but a single drawing uses either color-dependent (.ctb) or named (.stb) plot styles — not both simultaneously. You can convert drawings between the two systems if needed.

What happens if I plot a drawing that references a CTB file I don’t have?

AutoCAD will either prompt you to locate the missing CTB, use a default plot style, or the plot will not match the intended appearance. Place the missing CTB in your Plot Styles folder or ask the sender for it.

How do I prevent certain layers from printing?

Set the layer property to No Plot in the Layer Properties Manager, or map the layer’s color to “No Plot” in a CTB, or assign a named plot style with plot turned off in an STB and apply it to the layer.

Why do lineweights look different on-screen vs. printed?

On-screen display uses lineweight visualization which depends on zoom and workspace settings; prints use actual plot style lineweight values and plotter/PDF scaling. Always check with the Preview.

Can plot styles control color output (color vs grayscale)?

Yes. Plot styles can force colors to print as specific output colors or convert them to grayscale. In the Plot Style Table Editor you can set color mapping or choose grayscale output in the Plot dialog.

How do I share plot styles with my team?

Copy the .ctb or .stb files into a shared network folder or the company template folder and instruct everyone to add that folder to their AutoCAD plot style search path, or distribute via your CAD standards templates.

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