CAD Dictionary

What is an AutoCAD PMP file?

What is an AutoCAD PMP file?

An AutoCAD PMP (plotter model Parameter) file is a text-based configuration file that defines low-level plotter/printer parameters used by AutoCAD to produce accurate printed output. PMP files store device-specific details such as pen assignments, line widths, calibration offsets, print resolutions and other model-level settings that control how a plotter or large-format printer renders a drawing.

PMP files are usually used together with a .pc3 (plotter configuration) file or the system plotter settings. While a PC3 controls the higher-level configuration and mapping inside AutoCAD, the PMP contains the device model parameters that tell the plot engine how to translate drawing instructions to the physical hardware.

Why PMP files matter

  • They let you customize and fine-tune printing for a specific plotter or printer model.
  • They help ensure consistent output across different users and workstations.
  • They are useful for calibration, specialized printing (large-format posters, high-res engineering prints) and when default drivers do not produce correct results.
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How PMP files are structured (overview)

  • PMP files are plain text, so they can be opened in any text editor.
  • They contain key/value parameters (device capabilities, resolution, motor steps, pen mapping, scaling offsets).
  • The exact syntax varies by plotter model and AutoCAD version—do not change unknown parameters without backing up.

Step-by-step: Create or obtain a PMP file (beginner-friendly)

Step 1 — Determine if you need a custom PMP

  • If your plots are mis-scaled, have missing pens/lineweights, or show incorrect resolution, a custom PMP may be needed.
  • If the supplied driver produces accurate results, you likely do not need to edit PMP.

Step 2 — Access AutoCAD Plotter Manager

  • Open AutoCAD, then open Plotter Manager (Application menu → Print → Manage Plotters, or type PLOTTERMANAGER).
  • This opens the folder that contains your installed PC3 and PMP resources.

Step 3 — Add or edit a plotter configuration

  • To create a new configuration, use Add-A-Plotter Wizard and follow the prompts to install/select the correct driver. The wizard typically creates the necessary PC3 and often the PMP data automatically.
  • To modify an existing configuration, select the PC3 in Plotter Manager and choose Properties → Device and Document Settings to change common options.

Step 4 — Locate the PMP file

  • PMP files are usually located in the same plotter folder used by AutoCAD (user profile or AutoCAD installation “Plotters” folder). If a specific PMP was created, you will find it in that folder or referenced by the PC3.
  • If you cannot find it through the UI, check the AutoCAD plotters folder under your Windows profile (for example: AppData\Roaming\Autodesk\AutoCAD… → Plotters) or the program installation plotters folder.

Step 5 — Back up before editing

  • Always copy the original PMP (and the .PC3 file) to a safe location before making any changes.
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Step 6 — Edit carefully (text editor method)

  • Open the .pmp file in a plain text editor (Notepad, Notepad++).
  • Modify only the parameters you understand (for example, resolution, calibration offsets, or pen assignment lines).
  • Save and then restart AutoCAD so it reloads the plotter settings.

Step 7 — Test and iterate

  • Plot a small test drawing at the target paper size and scale.
  • If results are good, test a final print. If not, revert to the backup PMP and try incremental changes.

Alternative methods (safer and often preferred)

  • Use PC3 settings and the Add-A-Plotter Wizard to adjust configuration instead of editing PMP directly.
  • Use the printer/plotter manufacturer’s driver and utilities — manufacturers often provide calibration tools that create correct PMP-like settings.
  • Use CTB/STB plot style tables to manage pen colors and lineweights if your goal is to control line appearance rather than low-level device behavior.
  • Export and import plotter configuration files across machines via the Plotter Manager rather than manual text edits.

Common errors and how to fix them

  • Problem: Plotter not listed or unavailable

    • Fix: Reinstall the printer/plotter driver, run the Add-A-Plotter Wizard, and ensure PC3/PMP files are in the AutoCAD plotters folder. Check Windows printer sharing/permissions.

  • Problem: Output is blank or missing elements

    • Fix: Verify pen mappings and plot style (CTB/STB). Make sure the PMP/PC3 specifies the correct color-to-pen assignments and that lineweights are not set to zero.

  • Problem: Incorrect scaling or offsets in prints

    • Fix: Check calibration and paper size parameters in PC3 and PMP. Recalibrate axes and verify units (inches vs mm). Test with a calibration grid.

  • Problem: Fonts or raster images missing/garbled

    • Fix: Ensure fonts are embedded or installed, use TrueType or SHX as appropriate, and confirm raster resolution settings in PMP/PC3. Update plotter driver if necessary.

  • Problem: Changes not applied after editing PMP

    • Fix: Close and restart AutoCAD. If still not applied, confirm that the PC3 references the edited PMP and that file permissions allow read access.
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Best practices and tips

  • Always back up your original PMP and PC3 files before editing.
  • Prefer vendor tools or the Add-A-Plotter Wizard over manual edits when possible.
  • Use test prints after each change; make one change at a time so you can isolate causes.
  • Keep a versioned copy of working PMP files (e.g., PMP_v1, PMP_v2) to rollback quickly.
  • Store shared PMP/PC3 files on a network location if multiple users must use the same configuration.
  • Use CTB/STB for most pen/lineweight control; reserve PMP edits for device-specific calibration and features.
  • Document any custom changes in a README included with the PMP to help other users.

FAQ

What is the difference between a .PMP and a .PC3 file?

.PMP contains low-level plotter model parameters (device capabilities, calibration, pen mapping), while .PC3 is an AutoCAD plotter configuration file that links higher-level AutoCAD settings to the printer/plotter and may reference a PMP for device-specific data.

Can I create or edit a PMP file manually?

Yes — PMP files are plain text and can be edited with a text editor, but you should back up originals and only change parameters you understand. When possible, use AutoCAD’s Plotter Manager or manufacturer tools.

Where are PMP files stored?

PMP files are typically stored in your AutoCAD Plotters folder (either under your Windows user profile AppData\Roaming\Autodesk or the AutoCAD installation directory). Exact paths vary by AutoCAD version.

Will editing a PMP file affect other users?

If the PMP/PC3 is shared on a network or used by multiple workstations, changes will apply to all users who reference that configuration. Use network-managed copies carefully and maintain backups.

How do I revert changes if a PMP edit breaks printing?

Replace the edited PMP with your backup copy or a previous working version. Restart AutoCAD and retest. If necessary, remove and re-add the plotter using the Add-A-Plotter Wizard.

Can I use a PMP file across different AutoCAD versions?

Often yes, but compatibility can vary. Test the PMP in the target AutoCAD version and keep backups. If issues arise, recreate the PC3/PMP for the specific AutoCAD release using the Add-A-Plotter Wizard.

What should I do if my plotter produces mis-scaled prints after changes?

Check units (inches vs millimeters), paper size, and calibration offsets in the PC3/PMP. Run a printed calibration grid, adjust offsets or scaling parameters, and test again.

Are there risks to editing PMP files?

Yes. Making incorrect changes can produce poor or unusable output. Always backup, use manufacturer tools if available, and document modifications.

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