Blender LOD Tools

This add-on enables real-time LOD preview and screen size authoring directly in the Blender viewport. The aim of this tool is to speed up the LOD setup process by reducing the need to export and switch back and forth between Blender and the simulation. This tool is designed to be used for any kind of model that can be used in Microsoft Flight Simulator, whether it is a SimObject like an aircraft:

Or a static object designed for scenery:

The add-on generates LOD Viewer objects in your scene for each LOD group defined in the MSFS 2024 exporter, and each LOD Viewer will use a Geometry Nodes modifier to emulate the LOD selection system of the simulation engine. Note that the LOD Viewers directly use the objects in you scene, so there is no need to export any glTF to be able to preview the LODs in Blender.

LOD Viewer Generation#

Before using the LOD Viewer tool, the object LODs must be set up in the MSFS 2024 exporter panel, as the tool will use the export hierarchy in the visualisation process. Once that is done you can then do the following:

• Open the LOD Tools from the right side panel and then click the Generate LOD Viewers button to create the LOD Viewer objects for your scene.

  

• A settings pop-up will appear with the following options:

  Option	Description
  Align LOD Viewer To Source	Places each LOD Viewer at its source object’s location. When disabled, viewers are placed at the world origin.
  Offset	Offsets LOD Viewers along the chosen axis so source and LOD Viewer objects are visible side by side. The offset distance equals the scene’s bounding box size along that axis.
  Target	Chooses which objects get LOD Viewers. Select All to generate for the whole scene, or Checked to pick specific LOD group entries from the list.

• In Checked mode, the Target list is displayed and shows one entry per LOD group found in the exporter (see here for more information).

  

• You can filter entries using filters in the bottom panel:

  

• Click Okay to generate the viewers. A new –LOD Viewers– collection is created, containing one LOD Viewer per chosen LOD group.

  

Once this has been completed, you will be able to see a visualisation of the LODs, next to a list of the source objects, and the viewport has automatically switched to the LOD Camera mode (shown by the “LOD Camera Active” label at the top of the viewport), letting you move around and see LOD transitions update in real time. From now on, when needed, you can select LOD Viewers and adjust their location in the scene.

Regenerating After Edits#

Any time you move or edit source objects, or add/remove LODs from an exporter LOD Group, you will have to regenerate LOD viewers. If you don’t do this, the LOD preview and stats (vertex count, bounding sphere size, LOD origins, etc…) will not be correct. The process for regenerating the LOD preview is simplly a case of clicking Generate LOD Viewers again to rebuild them (existing LOD Viewers are deleted and recreated). Note that you can hold ⇧ Shift while clicking the Generate LOD Viewers button to skip the popup and reuse the last-used settings.

Clearing LOD Viewers#

At any time you can click the Clear LODs button to stop the LOD preview and remove all LOD Viewers from the scene.

Rules for LOD Viewer Objects#

LOD Viewers are objects with a Geometry Node Modifier that emulates the simulation render engine LOD selection system:

The following rules should be followed when working with LOD Viewers:

• You cannot edit LOD Viewer objects

• You cannot remove LOD Viewer object modifiers.

• LOD Viewers can be moved and rotated, but cannot be scaled or duplicated.

LOD Group Detection#

LOD Viewers are generated from the LOD groups found in the exporter panel hierarchy, which is why the Blender Exporter must be set up before creating LOD Viewers. Note that in the exporter, when using the Objects or Collections mode, you may need to press the Reload LOD Groups button before generating LOD Viewers.

• LOD groups and their associated LOD Viewers with exporter set to Objects mode :

  

• LOD groups and their associated LOD Viewers with exporter set to Collections mode :

  

• In Presets mode, a LOD group is a preset group containing one preset per LOD, ordered alphabetically:

  

LOD Viewer Origin#

LOD Viewer objects use the same origin they would have when exported as glTF, since this ensures a correct preview for modular scenery and aircraft. However, export settings that reset object transforms during export are supported, including those with Reset Origins in the exporter settings where both modes are supported

• All Roots#

  

• Per Objects#

  

Render Preset#

The Render Preset controls the LOD Factor, which determines how screen size is scaled in-game, and it emulates the simulation render presets andset by the Objects Level of Detail render setting:

The render preset being used can be set in the LOD Tools panel. However, if needed, you can override this global setting and set the LOD Factor manually using the Render Preset button (here a LOD Factor of 1 corresponds to 100% in the simulation settings, 0.5 to 50%, etc…):

The Render Preset can be changed in real time and will directly affect the LOD preview:

Screen Size Setup#

Screen Size From Exporter#

When the Blender Exporter is set to Objects or Collections mode, created LOD Viewers will use the screen sizes set in the exporter panel. If a screen size is set to 0, the tool falls back to the minimum screen size the engine computes from vertex count.

In Presets mode, screen sizes cannot be set in the exporter, so LOD Viewers use the engine-computed minimum based on vertex count. In this case, you can still edit these screen size values manually.

Editing Screen Size#

Screen sizes can be adjusted in real time from the right panel in the Active LOD Viewer tab, for example here we have adjusted the LOD0 screen size from 50% to 80%:

Note that:

• You can press ⎇ Alt + ⏎ Enter while editing a screen size field to apply the same value to all selected LOD Viewers.

• You can also right-click a field and choose Copy Single To Selected.

Sending Screen Sizes to the Exporter#

Click Send to exporter to push your screen size edits back to the exporter panel.

The Send to exporter popup lets you choose which LOD Viewer screen sizes to send:

• Active LOD Viewer - Sends the screen sizes of the active LOD Viewer.

• All LOD Viewers - Sends the screen sizes of all LOD Viewers.

• Selected LOD Viewers - Sends the screen sizes of the selected LOD Viewers.

Each LOD Viewer screen size setup is sent to the exporter individually. Note that the Send to exporter option is available when the exporter is set to Objects or Collections mode, but disabled in Presets mode. In Presets mode, screen sizes must be copied manually into the XML files.

LOD Camera#

LOD transitions are only visible while LOD Camera mode is active, which can be toggled with the LOD Camera button:

Camera Focal Length can be tweaked using the view panel, and will have a direct effect on LOD preview (You may have to increase the clip end value when viewing a LOD from a far distance):

Note that only one 3D viewport can have the LOD Camera enabled at a time, but you can easily switch between viewports using the LOD Camera button. In the image below, we set LOD Camera in another view:

In addition you have the following extra controls:

• Use the ⌃ Ctrl + ␣ Space hotkey combo to switch to fullscreen.

• You can create a new window using the Duplicate Area Into New Window button and enable the LOD Camera inside it.

  

• For smooth zoom in/out, you can hold ⌃ Ctrl + middle mouse button in viewport.

Debug Features#

Some of these debug features reproduce those available in the simulation, and they can be toggled by checking/unchecking the “Debug” checkbox.

• Active LOD Viewer Stats#

  Displays active LOD Viewer statistics in a table shown in the bottom-left corner (active LOD stats are highlighted in orange):

  
  NOTE

  Vertex count reflects the in-simulation count (accounting for UVs, normals, vertex colors, and other attributes), not the raw Blender count. It may deviate slightly from the engine’s result but they should be close enough for analysis of your models.

• Debug Text overlays#

  Display an overlay on top of each LOD Viewer object in the viewport (including: LOD Name, LOD Index, LOD Screen Size, LOD Min Size, LOD Distance and Vertex Count):

  

• Display Bounding Spheres#

  Display the bounding spheres as wireframes around the objects:

  

• Force Active LOD#

  This ignores the LOD Camera and forces a specific LOD index:

  

Tips#

Hide Collision / Occluders#

• Disabling Show in Viewport for individual source objects (or an entire collection) in the Outliner using the button will also hide them in the LOD Preview.

  

• Keeping collision and occluder objects in dedicated collections makes it easy to hide them all at once during LOD Preview.

• You can hold ⌃ Ctrl while clicking on the button to hide the entire collection.

Improving Viewport Performance#

LOD Preview can slow down the viewport when previewing hundreds of object LODs. To improve the FPS you can:

• Hide the source objects, which can give a significant performance boost. Hiding source objects using the button in the Outliner does not affect the LOD Preview.

  

• Limit the number of LOD Viewers by selecting fewer items in the Generate LOD Viewers panel.