rdLODtools Tutorial 13 – Creating new reduced meshes from LODs

A lot of assets coming out now have a very large poly count, Nanite handles this nicely once in game, and when packaged, a compressed set of data is saved – but their source disk foot print can be huge.

When working with a team through SVN – it can be tedious sending and receiving these large files when the final output is a much lighter weight footprint. It can be a waste of time and bandwidth.

This is where this new tool comes in. Version 1.44 of rdLODtools allows you to extract a LOD from a mesh, storing just the geometry used by the reduced LOD.

This tutorial is going to optimize a Megascans Cliff mesh. The original mesh comes in at 66MB – we’re going to get it down to less than 300KB, without too much noticeable difference.

Step 1. Download the mesh

The mesh being used here is called “Desert Western Ledge Rock Large 08” and can be downloaded from MegaScans Bridge. Note: MS have different qualities available to download – we’re using their highest resolution mesh (Nanite) as an example – often meshes only come as high res in content products.

Now you’ll have this folder in your Megascans/3D_Assets/ Folder:

Note the size of the original mesh:

Step 2. Turn off Nanite

Turn off Nanite for the mesh by right-clicking and selecting “Disable Nanite” from the menu. This isn’t necessary if you’re just going straight to extracting, but if you want to check how it looks, you’ll need it LOD based.

Step 3. Create a new LOD with a small Reduction Value

Now right-click on the mesh and choose the “Set Number of LODs->2” from the rdLODtools Tasks menu.

In the window that opens, set the 2nd LODs Reduction value to 0.02 (2%) and click “Set”.

Step 4. Extract the Reduced LOD

Now Right-Click on the asset and select “Tasks->Extract Reduced LOD->1” from the rdLODtools section of the context menu.

This creates a new mesh with the same name as the original mesh, but in a subfolder called “rdReduced” – with just the reduced mesh data stored.

Step 5. Done – check the size.

You can see the disk foot-print from the Meta data – the new mesh comes in at 292KB:

And here you if you look closely, you’ll notice some loss of detail close up, but as you past it to the next way point it’s probably not going to stand out:

If you’re wanting to replace the original meshes with the newly created ones – you can exit out of the Unreal Editor, navigate to the folder containing the meshes, then copy/paste-replace the meshes from the “rdReduced” folder into it’s containing folder.