# LN LODs PRO Addon for Blender (Version 4.0.2)

## What It Does

LN LODs Calculator automates Level-of-Detail setup for Microsoft Flight Simulator 2020 and 2024. If you make aircraft or scenery, this tool saves you hours of manual LOD tweaking.

**In a nutshell:** Name your collections `_LOD00`, `_LOD01`, etc., click a button, and the addon calculates the correct screen-size thresholds for the Asobo Exporter — calibrated to match how MSFS actually counts vertices.

## One Engine, Two Editions

The Free and Pro editions now share a single, unified core — the same calculation engine, the same interface, the same accuracy. Every improvement, fix, or performance gain lands in both editions simultaneously.

- **Free** — Full LOD calculation and exporter integration. Everything you need to get correct LOD values into the sim.

- **Pro** — Everything in Free, plus the real-time LOD Viewer for testing your LOD transitions inside Blender before you export.

No separate installs. No catching up. Upgrade any time.

## Quick Start

1. Name your collections: `MyModel_LOD00`, `MyModel_LOD01`, `MyModel_LOD02`...

2. Put your mesh objects into the right collections.

3. Open the **LN LODs** tab in the 3D Viewport sidebar.

4. Click **"Calculate LOD Sizes"** — results appear with a progress bar.

5. Click **"Set LOD Values in Asobo Exporter"** — done.

That's it. The exporter will use the correct thresholds and your LODs will transition smoothly in-sim.

## Features

### For Everyone (Free)

- **One-click calculation** — Scans all your LOD collections and computes screen sizes using the official Asobo reference curve. A progress bar keeps you informed on large scenes.

- **Accuracy you can trust** — Counts vertices the same way the exporter does: accounts for UV seams, split normals, vertex colours, and tangents. What you see is what the sim gets.

- **MSFS Exporter integration** — Writes results directly into the Asobo Multi Exporter's LOD groups. No copy-pasting.

- **Screen Space Margin** — Adds a safety buffer (2-3% recommended) to prevent LOD flickering in-sim.

- **Smart collection handling** — Optionally skip hidden collections so they don't interfere with your calculation.

- **Smart alerts** — Empty collections are clearly flagged; collections exceeding the sim's practical range are highlighted in red so you know to optimise further.

- **Clear Data** — One button to wipe all results and start over, no restart needed.

- **Exporter status check** — If the MSFS Exporter addon is missing or disabled, you'll see a clear warning in the panel.

### Pro Only (LOD Testing Mode)

See exactly how your LODs will behave in MSFS — right inside Blender:

- **Real-time LOD simulation** — Move your camera around and watch LODs switch at the exact distances they would in the sim.

- **Instant LOD switching** — Modifiers are evaluated on the fly so switching between LODs is instantaneous, even on complex meshes with heavy modifier stacks.

- **Collection isolation** — Only the currently-active LOD is visible during testing; all others auto-hide, so you see exactly one LOD at a time with no visual clutter.

- **Per-group control** — Toggle entire model groups on or off in the viewer to focus on specific parts without re-scanning.

- **Bounding sphere visualisation** — Yellow wireframe spheres show the coverage radius for each LOD group. Toggle them on or off.

- **Coverage readout** — Live percentage display shows how much of the screen each LOD occupies. Toggle it on or off.

- **Tweak on the fly** — Adjust individual LOD thresholds using sliders and send the refined values straight to the exporter without re-calculating.

- **Auto viewport cleanup** — Overlays, grid, gizmo, 3D cursor, and object origins all hide automatically when you enter testing mode so you can focus purely on LOD transitions. Everything restores when you exit.

- **One undo to restore** — Press Ctrl+Z after testing and everything goes back to exactly how it was.

- **Exit safely** — Press ESC or right-click-and-release to exit. The viewport, overlays, and collection visibility are all restored reliably.

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## Usage Instructions

### MSFS Multi Exporter Setup

1. Enable the **MSFS Asobo Multi Exporter** addon.

2. In the exporter's Objects tab, turn on **"Grouped By Collections"**.

### LOD Naming

Ensure your LOD collections end with `_LOD00`, `_LOD01`, `_LOD02`, etc. or `_LOD0`, `_LOD1`, `_LOD2`, etc. Examples:

- `MyModel_LOD00`

- `MyModel_LOD01`

- `MyModel_LOD02`

Place all relevant mesh objects into the respective collections for each LOD.

### Calculating LOD Values

1. Go to the **LN LODs** tab in the Blender Sidebar.

2. Click **"Calculate LOD Sizes"** to compute screen sizes for each `_LODxx` collection.

3. Review the results: collection name, vertex count, and recommended screen size %.

4. Adjust the **Screen Space Margin (%)** to account for minor discrepancies between Blender's vertex calculations and the final GLTF/Asobo pipeline. We recommend at least 2-3%.

5. Click **"Set LOD Values in Asobo Exporter"**. The plugin sends the results to the Asobo Multi Exporter, rounding up decimals to the next integer.

6. Press **"Open README"** to open this file in your system's text viewer.

### Using LOD Testing Mode (Pro)

1. Click **"Refresh LOD Viewer List"** to load your LOD groups.

2. Click **"Enter LODs Testing Mode"**. (Loading testing mode might takes some time, but makes LOD switching instant with our new pre-baking method)

3. Move your viewport camera around — watch LODs swap in real time. Only the active LOD is shown; everything else auto-hides.

4. Expand the **"Show LOD Thresholds"** section to enable/disable groups and adjust individual LOD sliders.

5. When you're happy, click **"Send Tweaked Values to Exporter"**.

6. Press **ESC** or right-click-and-release to exit testing mode. The viewport and all objects restore to their original state.

### Tips

- **Start with 2-3% margin.** This small buffer prevents the sim from constantly swapping LODs at transition boundaries. You can adjust per project.

- **Test at different distances.** Zoom all the way out and all the way in to check every LOD transition.

- **Use per-group toggles.** In Pro, disable groups you're not working on to speed up testing and reduce visual noise.

- **Check the warning banners.** If the MSFS Exporter isn't detected, the panel will tell you what's wrong.

- **Simple objects need margin too.** If your LOD value rounds to 0 but the object is visible, the margin pushes it to 1 so it doesn't disappear.

- **Use named LOD patterns consistently.** `_LOD00`, `_LOD01`, `_LOD02` or `_LOD0`, `_LOD1`, `_LOD2` both work, but don't mix styles in the same project.

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**NOTE: THIS IS TO MINIMIZE LOD POPPING.**

Any LOD collection with a value above `00.00%` gets automatically translated to **1** when sent to the exporter **if any Screen Space Margin is specified**.

Otherwise, it will remain 0. If you wanna set 0.5 (minimum VSS defined by Asobo) you can set it manually afterwards.

Bear that in mind when building very simple objects!

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## Support

For issues or feedback, contact **Chris "Losco Nosciuto" Da Ros** on his [Discord server](https://discord.gg/ZGMmYe3MvN).

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## Version History

### Pro Changelog

**4.0.2 Pro**

- Unified core codebase — Free and Pro now share the same calculation engine and UI. Every core improvement benefits both editions immediately.

- Dramatically improved calculation speed for large scenes, with progress bar feedback.

- Asobo-compliant interpolation for smoother, more reliable LOD transitions.

- 1:1 vertex count fidelity with the MSFS exporter — what you see is what the sim gets.

- Coverage formula now matches MSFS 2020 and 2024 exactly: `coverage = radius / distance x 1000`, clamped to 1000 at the bounding sphere surface.

- Cleaner Asobo exporter detection with status banners in UI.

- Improved bounding sphere precision for more realistic LOD transition testing.

- Progress feedback during calculation and overall reliability improvements.

- Streamlined developer mode (backend only) and general polish.

- Collection isolation during testing — only the active LOD is shown; others auto-hide.

- Per-group enable/disable toggles in the viewer.

- Auto viewport cleanup on testing entry (overlays, grid, gizmo, cursor, origins).

- Modifier stack baking for instant LOD switching. (Loading testing mode might takes some time, but makes LOD switching instant)

- Smart alerts for empty and out-of-range collections.

- Clear Data button to reset results.

**3.0.5 Pro**

- Greyed out the "Calculate LOD Sizes" button when in Testing Mode.

- Introduced a new button to send manually tweaked data from the Viewer to the Exporter.

**3.0.1 Pro**

- Corrected edge cases for bounding sphere calculations. So far should be consistent (center -> furthermost vertex = radius from 0,0,0).

**3.0.0 Pro**

- Introduced **LN LODs Viewer** for real-time LOD Testing Mode.

- Added bounding sphere calculations for vertical coverage (MSFS style).

- Overlays can be hidden while bounding spheres and coverage text are shown in the viewport.

- Supports toggling bounding-sphere wireframe and numeric coverage readouts.

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### Free Changelog (Also applies to 3.x.x Pro)

**2.8.1**

- Blender 4.2 LTS compatibility.

- Updated ARRAY values for VSS/Vert Count.

- Slightly reworked interpolation logic.

**2.7.5**

- This free version excludes the real-time LOD Viewer module.

- Basic calculations and auto-set LOD values remain the same.

- Fixed a bug with "Hide Hidden Collections" — hidden collections and children of hidden collections are now correctly excluded.

**2.7.0**

- **Expanded Data Array** — Greatly increased reference points for more accurate mapping from vertex counts to screen space.

- **New Interpolation Method** — Replaced linear interpolation with a smoother curve for more natural LOD transitions.

- **Dynamic Vertex Limits** — Removed the fixed 2M vertex limit.

- **Boundary Handling** — Minor cleanups and improved handling at extreme values.

**2.6.0**

- Added **"Hide Hidden Collections"** to exclude hidden collections from calculations.

**2.5.0**

- **Reworked Vertex Counting Algorithm** — Now accounts for splits from multiple UVs, split normals, vertex colors, tangents. Minimizes mismatch between Blender's internal count and the sim's final vertex count.

**2.2.0**

- **Modular Plugin Structure** — Split into multiple scripts. Enables backend expansion and easier bugfixing.

**2.0.0**

- Recognises both single-digit and double-digit LOD suffixes (`_LOD0`, `_LOD01`, etc.).

- Vertex counting logic now triangulates meshes, adding 2 verts for quads, `(n-3)` for ngons.

**1.8.0**

- Replaced fixed 2% margin checkbox with a dynamic float input.

- Enhanced error handling, debug messages, UI clarity.

- Red highlighting for out-of-range collections.

- LOD collections exceeding vertex limits are included in results but marked as out of range (displayed in red).

**1.6.0** (Initial Release)

- Basic LOD screen size calculation and direct integration with Asobo Multi Exporter.

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**Happy blending!**