Advanced Configuration


Contents

Prepar3D.cfg

The Prepar3D.cfg configuration file stores simulation and graphics options. If you are an advanced user and feel comfortable editing it directly, you can open the Prepar3D.cfg with any text editor. Typically, all tuning should be done through the Options user interface.

How to Make Changes to your Prepar3D.cfg Configuration File

  1. Locate the Prepar3D.cfg file in %APPDATA%\Lockheed Martin\Prepar3D v4
  2. Create a backup of the original Prepar3D.cfg to restore if issues occur
  3. Right click file and click Open, Edit, or if prompted choose Notepad or another text editor
  4. Add the below text into the specific sections to make the desired change
  5. Save the newly updated Prepar3D.cfg and restart Prepar3D

Advanced Tuning Options

The following entries are not written into the Prepar3D config by default, but may allow users to fine tune performance for specific training goals. Typically, users should not need to modify any configuration values for a stable and performant simulation experience, but the following tweaks may help advanced users optimize further. Headings are enclosed in brackets and the entries are bolded followed by Performance Tuning Tips with the intended purpose of the fix.

[DISPLAY]

TextureMaxLoad=6

Non-Default entry. This entry will not exist in your Prepar3D.cfg file by default and must be added to the file.

Performance Tuning Tip:

This can induce stutters. Use multiples of 3 only such as 3, 6, 9, etc. This is perfect for photorealistic scenery

[TERRAIN]

SWAP_WAIT_TIMEOUT=30

Non-Default entry. This entry will not exist in your Prepar3D.cfg file by default and must be added to the file.

Performance Tuning Tip:

This variable is the number of frames that the terrain engine will wait for terrain textures to be loaded into video memory before forcing new tiles of terrain triangles to be rendered.

UseGlobalTerrainView=True

The default value is False.

Performance Tuning Tip:

By default, every camera has its own terrain view which requests texture and dem tiles near the camera to ensure that all cameras get a quality view of terrain. It is possible for cameras to share data and avoid the extra work required to manage multiple terrain views. For multi-view scenarios in which all views are near each other, it may be desirable to have views simply render the terrain tiles loaded by the default view. Setting this option to True will prevent all camera from creating a terrain view except for the default 3d view. This can help avoid texture flashing and terrain spikes that occur on some systems with multiple views and/or multiple video cards. This value can be overridden by the UseGlobalTerrainView entry in a given CameraDefinition allowing each camera to determine whether or not to create a terrain view. This setting will be engorged if Tessellation is not enabled.

[GRAPHICS]

AdvancedPresentationMode (Professional Plus Only)

This setting will change the order of operations used for rendering and displaying scenes. The default order is recommended for best performance. Changing presentation mode can help reduce latency. Changing presentation modes may cause visual artifacts in 3d scenes, so it is currently only recommended for use with training devices that primary rely on 2D panel windows.

AdvancedTextureUpdateMode = 1 (Professional Plus Only)

This setting can be used to change the order of operations for submitting texture updates to the GPU. Setting this to 1 will move the texture update earlier in the frame. This will reduce panel latency by one frame, but may affect performance.

[JOBSCHEDULER]

AffinityMask=14

Non-Default entry. This entry will not exist in your Prepar3D.cfg file by default and must be added to the file.

Performance Tuning Tip:

By default, Prepar3D will use all available processor cores. On machines with four or more cores, it will dedicate a core to rendering tasks. The easiest method for modifying the affinity mask is to open the windows calculator in programmer view, select the binary display mode, and flip the bits in the binary number displayed to select which cores the application should run on. Note that the cores are represented right to left.

[PANELS]

PANELS_ALWAYS_ON_TOP = 1

Docked panel windows will always display above docked windows with 3D views. Setting this setting will enable the same functionality with undocked windows. This is especially useful in full-screen mode, where undocking panels and placing them above an undocked 3D view may be desirable. Note that as of Prepar3D v4, panel views can now be docked into any floating window.

PANEL_UPDATE_MODE = 2

This setting controls panel update frequency.

[MAIN]

FIBER_FRAME_TIME_FRACTION=0.33

Non-Default entry. This entry will not exist in your Prepar3D.cfg file by default and must be added to the file.

Performance Tuning Tip:

This setting, which defaults to a value of .33 (33%), defines the percentage of each frame that is devoted to loading scenery. Increasing this number can reduce "the blurries", but it can cause stutters, and can also reduce the overall frame rate. Try reducing the number to the lowest level where you still get smooth scenery paging. This will vary depending on disk speed as well as the type of flying, as well as the selected scenery options.