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The Preferences dialog lets you customize how OpenRocket looks and behaves. Changes to most settings take effect immediately or the next time you open a relevant window.

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Accessing the preferences dialog

Open the Preferences dialog using any of these methods:
  • Edit > Preferences
  • Windows/Linux: Ctrl + ,
  • macOS: Cmd + ,

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General

The General tab contains application-wide settings. Interface language Select the language for the OpenRocket interface. Available languages include English, Czech, German, Spanish, French, Italian, Dutch, Polish, Portuguese, Turkish, Russian, Ukrainian, Arabic, Chinese, and Japanese. The System default option uses the language set in your operating system.
You must restart OpenRocket for a language change to take effect.
Many translations are incomplete or out of date. Missing strings are displayed in English. If you find errors or missing translations, please open an issue on GitHub or contribute via Crowdin.
UI theme Select the visual theme for the interface:
  • Auto (detect) — follows your operating system’s theme
  • Light (default) — the original OpenRocket light theme
  • Dark — a dark theme
  • Dark, high-contrast — a dark theme with increased contrast
You must restart OpenRocket for a theme change to take effect.
UI font size Adjust the interface font size. The default is 13. A restart is required for this change to take effect. User-defined thrust curves Specify one or more directories containing your own thrust curve files. OpenRocket scans these directories at startup in addition to its built-in ThrustCurve.org database. Separate multiple paths with a semicolon (;).
  • Add — select a directory to add
  • Reset — restore the default directory
Update checks
  • Always check for software updates at startup — notifies you when a new release is available
  • Check now — manually check for updates immediately
  • Also check for pre-releases — includes release candidates and beta versions in update checks
Other general settings
  • Open last design file on startup — reopens the most recent project when OpenRocket starts
  • Show warning when saving in RASAero format — alerts you when exporting to a format that may lose some information
  • Show warning when saving in RockSim format — same as above for RockSim format
  • Show confirmation dialog when discarding preferences — prompts for confirmation before discarding unsaved preference changes

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Design

The Design tab controls how the rocket design view behaves.
  • Position to insert new body components — choose whether OpenRocket always asks, inserts in the middle, or adds to the end
  • Position to insert new stages — same behavior for stages
  • Size of text in rocket design panel — controls label text size in the design view
  • Default Mach number for C.P. estimate — the Mach value used for center of pressure calculations in the design view
  • Always open leftmost tab when opening a component edit dialog — if disabled, the last-used tab reopens instead
  • Show confirmation dialog for discarding component changes — prompts before cancelling unsaved component edits
  • Show confirmation dialog for discarding simulation changes — prompts before cancelling unsaved simulation edits
  • Update estimated flight parameters in design window — recalculates and displays estimated flight parameters in the design view as you edit
  • Only show pod set/booster markers when selected — hides pod/booster instance markers unless the pod set or booster is selected in the tree

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Simulation

The Simulation tab controls simulation behavior and defaults.
  • Confirm deletion of simulations — prompts before deleting a simulation
  • Run out-dated simulations when you open the simulation tab — automatically re-runs simulations that are out of date when you switch to the Flight Simulations tab
  • Geodetic calculations — choose the coordinate calculation method used for Earth coordinates
  • Time step — the minimum time step for simulations; smaller values produce more accurate results but take longer to compute
OpenRocket uses optimized (adaptive) time steps. The actual time step varies throughout the simulation and may be larger than the configured minimum where precision is less critical.
  • Reset to default — restores all simulation options to their defaults

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Launch

The Launch tab sets default launch conditions for new simulations.
Settings in the Launch tab have no effect on simulations that already exist in your design. Only new simulations created after changing these settings will use the updated values.
  • Average windspeed — average wind speed relative to the ground
  • Standard deviation — measure of wind speed dispersion; the actual wind speed is within twice this value 95% of the time
  • Turbulence intensity — standard deviation divided by average wind speed; typical values are 5%–20%
  • Wind direction — direction the wind is coming from (0° = north, 90° = east, 180° = south, 270° = west)

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Units

The Units tab sets the measurement units used throughout the application. You can configure units individually for:
  • Rocket dimensions, motor dimensions, distance, velocity, acceleration, mass, force, total impulse, moment of inertia
  • Stability (primary and secondary) — options include mm, cm, m, in, cal (calibers), and % of rocket length
  • Line density, surface density, bulk density, surface roughness, area, angle, roll rate, temperature, pressure, wind speed, latitude, longitude
Use Default metric or Default imperial to set all units at once.

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Materials

The Materials tab lists all materials available in OpenRocket, including pre-installed materials and any custom materials you have added.
  • Pre-installed materials are shown in greyed-out text and cannot be deleted.
  • New — add a custom material
  • Edit — edit a material; editing a pre-installed material creates a new custom material with the same name rather than modifying the original
  • Delete — delete a custom material
  • Revert all — delete all user-defined materials
Editing materials does not affect existing rocket designs. Only designs created or modified after the change will use the updated material properties.

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Graphics

The Graphics tab controls 3D rendering and texture editing settings. Graphics editor Select the external application used to edit textures when you click Edit next to the texture field in a component’s Appearance tab:
  • Show Prompt — asks each time
  • Use Default Editor — uses the OS default for the file type
  • Command Line — specify the executable path and arguments for a particular editor
3D graphics
  • Enable 3D Graphics — if disabled, all 3D features are unavailable
  • Enable Anti-aliasing — smooths edges in 3D views
  • Use Off-screen Rendering — renders 3D graphics off-screen; improves performance on some systems but may cause issues on others
If you experience issues with the 3D view (such as the rocket appearing too small or rendering incorrectly), try toggling Use Off-screen Rendering.
Graphics changes take effect the next time you open a 3D window.

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Importing and exporting preferences

You can export your preferences to an XML file and import them on another machine. This is useful for sharing a consistent configuration across multiple computers or when helping others set up OpenRocket. Export preferences Click Export preferences at the bottom of the General tab. A file dialog opens where you choose the save location. Two options are available:
  • Export user directories — includes user-defined directory paths (e.g. thrust curve folders); disable this if the target machine uses different paths
  • Export window information (position, size…) — includes cached window positions and sizes; disable this for a clean layout on the target machine
Import preferences Click Import preferences at the bottom of the General tab and select the XML file to import.

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Resetting preferences

To reset all preferences to their factory defaults, click Reset all preferences at the bottom of the General tab.