Plotting in AutoCAD – Overview of Plotting, Key Terms, and Concepts

Introduction

Plotting in AutoCAD, often referred to as printing, is the process of converting your digital drawing into a physical copy or exportable digital format, such as a PDF. For engineers, architects, and designers, the ability to produce clear, accurate plots is essential for communication, review, and final documentation. However, the process involves more than just hitting “print.” Understanding AutoCAD’s plotting settings, scales, layouts, and output options is crucial for creating high-quality plots that accurately represent your design. This article provides a comprehensive overview of plotting in AutoCAD, including key terms, essential concepts, and steps to ensure your prints come out just right.

Key Terms and Concepts in Plotting

Before diving into the plotting process, let’s cover a few essential terms and concepts that will help you understand how plotting works in AutoCAD.

• Layout vs. Model Space: AutoCAD has two main workspaces—Model Space and Layout Space. Model Space is where you create your design at a 1:1 scale, while Layout Space is where you set up views, scales, and annotations for plotting. Layouts typically contain a viewport that displays the model at a specific scale for plotting.
• Viewport: A viewport is a window in a layout that shows a specific view of the model. You can adjust the scale of the viewport to fit the drawing onto a specific paper size.
• Plot Style Table (CTB and STB): A Plot Style Table controls how lines are printed, including line weights, colors, and styles. CTB (Color-Dependent Table) files assign properties based on color, while STB (Style-Dependent Table) files apply properties based on plot styles.
• Plot Scale: The plot scale determines the ratio between the actual drawing units and the plotted output size. For instance, a 1:100 scale means that 1 unit in the drawing equals 100 units on the paper.
• Page Setup: Page setup defines the plotter or printer, paper size, plot area, plot scale, and plot style table. Page setups can be saved and reused across different drawings for consistent output settings.

Step-by-Step Guide to Plotting in AutoCAD

Plotting in AutoCAD involves setting up your layout, configuring the plot settings, and executing the plot command. Here’s a breakdown of each step:

Step 1: Set Up the Layout for Plotting

AutoCAD’s Layouts are specifically designed for setting up and organizing plots. Each layout can contain multiple views and configurations, allowing you to prepare your drawing for various outputs.

1. Switch to Layout Tab: In your drawing, switch from Model Space to Layout Space by clicking on one of the Layout tabs at the bottom of the workspace (e.g., Layout1 or Layout2).
2. Create a New Viewport: Type MV (Make Viewport) in the Command Line and press Enter. Click and drag within the layout to create a viewport that displays your model. This viewport will be where you set the scale and view for the plot.
3. Set Viewport Scale: Click on the viewport, then use the Properties palette to set a specific scale (e.g., 1:100, 1:50). The scale determines how the model will appear in relation to the paper size when plotted.
4. Lock the Viewport: After setting the scale, lock the viewport to prevent accidental adjustments. Right-click on the viewport’s border, select Display Lock, and choose Yes.

Step 2: Configure the Plot Settings

Once your layout is prepared, you’ll configure the plot settings to control the output format, appearance, and scale.

1. Open the Plot Dialog Box: Type PLOT in the Command Line or click on the Plot icon in the Quick Access Toolbar. This opens the Plot dialog box, where you’ll configure the output settings.
2. Choose a Printer/Plotter: Select the printer or plotter you want to use from the Printer/Plotter dropdown menu. If plotting to a PDF, select DWG to PDF.
3. Select Paper Size: Choose the desired paper size (e.g., A4, A3, ANSI D). Ensure the selected size matches the paper size in the layout to avoid scaling issues.
4. Specify Plot Area: In the Plot Area section, choose what to plot—typically Layout or Window. Selecting Layout plots everything visible within the Layout tab, while Window allows you to specify a custom area.
5. Set Plot Scale: Ensure the plot scale matches the viewport scale set in Layout Space. For accurate scaling, use 1:1 in the Plot dialog if the layout scale is already set in the viewport.
6. Apply a Plot Style Table:
   • Select a CTB or STB file from the Plot Style Table (Pen Assignments) dropdown. This controls the appearance of lines and colors in the plot. CTB files are color-dependent, while STB files are style-dependent.
   • Common CTB files include monochrome.ctb for black-and-white plots and acad.ctb for color plots.
7. Preview the Plot: Click on Preview to see how the plot will look before printing. Check for any errors or adjustments needed, especially with line weights and scaling.

Step 3: Execute the Plot Command

After confirming the settings, you’re ready to plot.

1. Adjust Final Settings: If necessary, make final adjustments to the plot settings, including rotation (portrait or landscape) or center the plot.
2. Click OK to Plot: Press OK to start the plotting process. Depending on the selected output, AutoCAD will either send the file to the printer or generate a PDF.
3. Save the PDF (If Applicable): If plotting to a PDF, specify the file location and save. AutoCAD will create a PDF file of the drawing with the specified layout and settings.

Understanding Plot Style Tables (CTB and STB)

Plot Style Tables are essential for controlling line weights, colors, and styles in a plot. They ensure that drawings print consistently, regardless of the display color in Model Space.

• CTB (Color-Dependent Plot Style Table): Applies plot styles based on the color of objects. For example, objects drawn in red might plot with a specific line weight or color.
• STB (Style-Dependent Plot Style Table): Applies plot styles based on named plot styles, rather than colors. This offers more flexibility by allowing different line weights and colors regardless of the drawing color.

How to Apply a Plot Style Table:

1. Open the Plot Dialog Box and navigate to the Plot Style Table section.
2. Select a CTB or STB File: Choose a pre-existing file (such as monochrome.ctb for black-and-white) or create a custom CTB or STB file using the Plot Style Manager.
3. Adjust Line Weights and Colors: In the Plot Style Manager, you can assign specific line weights, screening, and colors to each color or style in the table.

Tips for Effective Plotting in AutoCAD

1. Use Page Setups for Consistency: Save common plot configurations as Page Setups to quickly apply them across different drawings or layouts.
2. Check Scale Compatibility: Ensure the plot scale in Layout Space matches the settings in the Plot dialog box to avoid discrepancies in printed output.
3. Preview Before Printing: Always preview the plot to catch any potential issues with line weights, scales, or layout alignment before committing to print.
4. Test Plot Styles: Test different plot style tables (CTB/STB) to determine the best fit for your project’s requirements, ensuring clarity in line weights and colors.
5. Save Custom Page Setups: Use the Page Setup Manager to save custom settings for specific layouts, which helps maintain consistency across drawings.

Practical Applications of Plotting in AutoCAD

Plotting in AutoCAD serves multiple purposes, each relevant to specific industries and design needs:

• Architectural Blueprints: Produce scaled, detailed prints of architectural plans with specific line weights and annotations for construction.
• Mechanical Engineering Drawings: Create technical drawings of machine parts with precise scales and line styles for manufacturing.
• Electrical Layouts: Generate clear, annotated layouts of wiring, circuit diagrams, and component locations for electrical projects.
• Civil Engineering Plans: Plot detailed plans of infrastructure projects such as road layouts, drainage systems, and topography maps.

Common Plotting Errors and Troubleshooting Tips

1. Lines Not Displaying Correctly: Ensure the correct plot style table (CTB/STB) is applied and that line weights are set appropriately in the Properties palette.
2. Scaling Issues: Verify that the viewport scale matches the plot scale in the Plot dialog box, and that the correct paper size is selected.
3. Layout Doesn’t Print as Expected: Check that the plot area is set to Layout if you’re working in Layout Space, or specify a custom window if plotting from Model Space.
4. Clipped Content: If parts of the drawing are clipped in the plot, make sure the plot area and viewport align with the intended view.

Conclusion

Mastering plotting in AutoCAD is crucial for producing accurate, high-quality prints that communicate design details effectively. By understanding the key terms, such as plot scales, plot style tables, and page setups, you can streamline the plotting process and create consistent, professional output for various applications. With the knowledge provided in this guide, you’ll be able to set up layouts, configure plot settings, and troubleshoot common issues, ensuring your designs look as good on paper as they do on the screen.

FAQs

1. What is plotting in AutoCAD?
   Plotting in AutoCAD is the process of printing or exporting a drawing layout, converting the digital file into a physical or digital format like PDF.
2. How do I set the plot scale in AutoCAD?
   Set the plot scale in Layout Space by adjusting the viewport scale, then match it with the scale in the Plot dialog box.
3. What is a CTB file in AutoCAD?
   A CTB file (Color-Dependent Plot Style Table) controls line weights, colors, and styles in the plot based on object color, allowing for consistent plotting.
4. How can I save a plot setup in AutoCAD?
   Use the Page Setup Manager to save custom plot configurations, which can then be applied to other layouts or drawings for consistent output.
5. Why is my plot not displaying correctly?
   Ensure that the plot scale, viewport scale, and paper size are aligned. Check the plot style table and preview the plot to identify any line weight or layout issues.