# Debugging LODs<no value>
Once you have your models setup you'll want to debug different things, one of them being the {{< glossterm >}}lod{{< /glossterm >}}s. To permit this, there are a number of tools available from the DevMode menus within Microsoft Flight Simulator 2024 and this page discusses those tools.

{{< callout context="note" title="NOTE" icon="outline/bulb" >}}

This page is included in the LODs section to provide a reference when you have your aircraft setup in the simulation, although it may not be relevant at this point right now in the tutorial.

{{< /callout >}}

 

 

### Check LODs Visually

The most important tool you'll have available to you for debugging your aircraft and scenery LODs is from the DevMode [Debug](../../../devmode/menus/debug_info/) menu: [Debug Model LODs](../../../devmode/menus/debug_info/debug-lods/).

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_1.png"
    alt="The Debug Model LODs Option" >}}

 

This will then open the Debug Lods window - which has numerous options that can be used for debugging - as well as show an overlay of information within the simulation. At this point we'd recommend that you add the package name to the **Package Name Filter**, as this will then filter the package details from the overlay, making it a lot easier to read. You can mouse-over the following image to see the difference this makes:

![Card Back](images/3_Models_And_Textures/Aircraft/lods/lod_debug_2.png)![Card Front](images/3_Models_And_Textures/LODs/debug/lod_debug_3.png)

 

You will also want to **un-**check the **Force User LOD 0** option. By default, the user aircraft is always on LOD x0, but un-checking this option will tell the engine to treat the player aircraft like any other SimObject and change LODs based on the camera position. With this un-checked you can use the [Developer Camera](../../../devmode/menus/camera/#dev_cam) to move around and see the LOD values change as the engine changes them:

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_4.gif"
    alt="Animation Showing The Changing LODs" >}}

 

Finally, you can view each LOD up close using a combination of the Developer Camera and the **Enable Force Active LOD** option, for example:

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_5.png"
    alt="Forcing An Active LOD" >}}

 

 

### Check LOD Resources

Once a flight is started, you can get detailed information about the model and the LODs from two different DevMode windows. The first is from the [The SimObject Statistics Profiler](../../../devmode/menus/tools_info/simobject-statistics/) window, on the **Global** tab. Here you can select your aircraft from the **Airplane** list, and when you expand the information you will see some detailed statistics on nodes, vertices, etc... as well as a button to either {{< button "Load" />}} a LOD (if it's not available yet) or a button to `Force LOD`:

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_6.png"
    alt="The SimObjects Stats Window" >}}

{{< callout context="note" title="NOTE" icon="outline/bulb" >}}

The `Force LOD` button will not do anything if the [Debug Model LODs](../../../devmode/menus/debug_info/debug-lods/) **Enable Force Active LOD** option is enabled.

{{< /callout >}}

 

The other option you have is to use the [Current Container](../../../devmode/menus/tools_info/simobject-statistics/#current_container) tab, where you can quickly **Profile** the aircraft to get an isolated performance overview, and then view the **Live Stats**. The Live Stats section permits you to see a vast amount of information about the different parts of the aircraft model, and you can use the **Search For An Object** filter to find any specific model part, and then set the following columns (which can be done using the `Edit Columns` button): *LOD*, *Draw Calls*, *Static Vertex Count*, *Original Min Size*, *Max Draw Calls*, *Draw/MaxDraw Ratio*, *Max Vertex Count*, *Vertex/MaxVertex Ratio*.

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_7.png"
    alt="The Statistics Profiler Window" >}}

The information here is colour coded so that if you see any field with an orange background then you know that the value is on the limit of what is optimal for the engine, while a red shaded cell is sub-optimal and should be adjusted to get the best performance.

 

Finally you can use the various debug options available from the [Debug LODs](../../../devmode/menus/debug_info/debug-lods/) window, specifically the [LOD Limits: draw count](../../../devmode/menus/debug_info/debug-lods/#LODLimits_drawcount) and [LOD Limits: vertices](../../../devmode/menus/debug_info/debug-lods/#LODLimits_vertices) options, although the others can also be useful:

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_2.png"
    alt="Additional Model LOD Options" >}}

 

It is also possible to enable/disable the [LOD selection system](lod-selection-system/) by changing the [LOD Limits](../../../devmode/menus/debug_info/debug-lods/#ActivateLODLimits) option:

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_8.png"
    alt="The Debug LOD Window" >}}

This should be done *before* you start any flights, but if you enable/disable this option during a flight, you will have to exit the flight, wait 20 seconds, then start a new flight, to see any effect.

 

 

### How To Find Bad LODs

The instructions below are a basic guide on how to check the LODs for an asset:

 

-   Set your desired graphics quality from the Microsoft Flight Simulator 2024 options ("*High*" is recommended).
-   Open the [Debug LOD](../../../devmode/menus/debug_info/debug-lods/) window, and check if "**Activate LOD limits**" is active. If it **is**, then you have to do the following:
    -   Disable "Activate LOD limits".
    -   If in a flight, go to the main menu, then wait 20 seconds before continuing.
-   Load a flight at your preferred location.
-   Now choose your preferred debugging method:
    -   Using the **Debug LOD** window:
        -   Check the "**LOD Limits: vertices**" checkbox  

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_10.png"
    alt="The LOD Limits: Vertices Checkbox" >}}

        -   Any model display that colors red means the currently active LOD will be culled under the new system. If a lower res LOD exists, it will switch to that, otherwise it will disappear completely.  

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_9.png"
    alt="An Example Of A Poorly Optimised LOD In The Simulation" >}}

    -   Using the [Statistics Profiler](../../../devmode/menus/tools_info/the-statistics-profiler/) tool:
        -   Click the "**Edit** **Columns**" button and select these columns: *LOD*, *Draw Calls*, *Static Vertex Count*, *Original Min Size*, *Max Draw Calls*, *Draw/MaxDraw Ratio*, *Max Vertex Count*, *Vertex/MaxVertex Ratio*.
        -   Make sure the "**Use Objects From** **Editor**" checkbox is disabled (to be able to view independent model stats).
        -   Any cell that appears in RED (over the limit) or ORANGE (close to the limit) is a value that needs to be optimized.  

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_11.png"
    alt="Example Of LODs Debugging In The Statistics WIndow" >}}

            You can also mouse over the LOD entries flagged in red or orange to get an idea of what the issue is:  

{{< image-center
    src="images/3_Models_And_Textures/LODs/debug/lod_debug_12.png"
    alt="The Statistics Profiler Tooltip Showing An Issue" >}}