World LOD

Overview

The World LOD dialog is used to generate LOD terrain and LOD building geometry for the world.

Data Fields and Buttons

• Worldspace list: List of all Worldspaces.
• Worldspace Stats: Editor name, in-game name, form ID, number of LOD terrain chunks, number of cells.
• Generate Terrain Meshes: Creates terrain meshes for the world from the local land geometry.
• Generate Terrain Textures: Builds texture and normal maps for the LOD terrain, also from the local land.
• Chop Terrain Texture: Allows you to instead build LOD terrain texture maps from a handpainted texture up to 8192x8192 in size. It does not build normal maps. (This might be changing - TBD)
• Combine Generated and Handpainted Terrain Textures:
• Generate Objects: Creates LOD geometry and texture maps for all refs in the world that are marked visible when distant.
• Generate Trees:

Notes

Terrain Mesh Generation

• The time that it takes the GECK. to generate LOD meshes is directly related to the number of "chunks" that it has to generate, which depends on the number of cells in your world space. For a small world (up to about 20 chunks) it may only take a few minutes; for a larger world space (20-50 chunks), the time increases to around 30-60 min; a world space with more than 50 chunks generally takes several hours. To generate an entire heightmap created in the heightmap editor (circa 1360 chunks) it will take around 2-3 weeks of non-stop generation.
• During the mesh generation process, it may seem as though the GECK has crashed. In some cases, this is true; in most cases, it is still generating new meshes and only appears to be frozen. (You can check this in the task manager by observing whether or not the GECK is using any system resources. If it is, it is still working. In the case of a crash, it is not likely to be using any resources. The GECK will typically use up to 100% of your system resources to generate LOD meshes.) If the GECK crashes during LOD generation, simply reopen the GECK and start the process again. Any LOD meshes that were generated in the previous session will remain and the editor will continue to process from where it left off.

Terrain Texture Generation

• Currently, all of the functionality that creates textures creates source TGA textures that need to go through the GECK build process to actually be visible in-game. When landscape LOD texture generation is complete, you will find the generated DDS LOD textures outside your Fallout3 game directory in Source\Textures TGA\landscape\LOD\(directory named as your worldspace).
• In order for the game to find your generated textures, you must copy this folder and place it in your Data\Textures\Landscape\LOD\ folder. You may delete the Diffuse folder and change the name of the DiffuseGenerated folder to Diffuse, or copy the files in the DiffuseGenerated folder to the Diffuse folder. (The game will look for the textures in the Diffuse folder but the GECK doesn't put them there by default.)

LOD Object Generation

• To generate LOD objects, you must provide the GECK with the necessary LOD meshes and textures.
• LOD meshes are generally located in the same folder as the original mesh but end with "_lod.nif". If you have not already done so, you must extract these files from your meshes.bsa archive to locate them in the correct directory. (Generally speaking, only objects with their Visible When Distant flag checked will have LOD meshes.)
• LOD textures can be determined in one of two ways: by opening the LOD mesh in NifSkope and expanding the NiTriStrips to find the BSShaderTextureSet (the textures will appear in the Block Details window beside the purple flower icons), or by running the Generate Object command and making note of the missing texture warnings that appear. (You will, of course, have to re-run the command to actually generate the objects once you have the textures in place.) You will need to extract both the diffuse and normal map textures and convert them to TGA format for the object generation process to work (see below).
• All textures for LOD objects must be in the TGA format or the editor will not process them. To convert your DDS textures to TGAs, open them in an image editing program like Irfanviewor the GIMP and "save as" TGA. (Default settings appear to work for the GIMP.)
• Your converted TGA textures must be placed in the Source\Textures TGA\ folder using the same folder structure that the game uses. For example, if your texture is in the Data\Textures\architecture\urban\ folder the TGA file must be located in the Source\Textures TGA\architecture\urban directory. (The Source\Textures TGA\ directory is located outside your Fallout3 Game Directory in the main Bethesda Softworks directory.)
• Once all of your textures have been extracted and converted, run the Generate Objects command. The editor will place the generated textures in your Source\Textures TGA\landscape\LOD\(directory named as your worldspace) directory. Copy the generated textures to the corresponding Data\Textures\Landscape\LOD\ folder. (If you do not remember to place your generated object textures here, objects will render in-game with purple textures.)

LOD Trees

• The capital wasteland worldspace is located at a coordinate of around 10500z. You should always create a new worldspace far above this z coordinate; that means at a minimum of 3000z above 10500z. Otherwise, you may get floating trees (LOD) in the sky or above the ground when you change worldspaces.

LOD Water

• LOD is only generated for terrain above the waterline. If no distant LOD terrain exists on the other side of a large body of water, the sky will be visible underwater and the sea bed will visibly terminate at the edge of the immediately rendered area. Also, a visible seam may appear between the water plane and water LOD. For these reasons, it is advised that you enclose large bodies of water with distant land.
• Be aware that when creating LOD for worldspaces with worldspace autowater that you will sometimes get big surface holes in the water LOD that are not easy to fix.
• Make sure that your LOD water type matches your world space water type to avoid unsightly mismatches where the water plane meets the LOD water. Water type and LOD water type are set in the World Spaces dialog.

Regenerating LOD Data

• Before recreating LOD data for a worldspace, it is important to remove existing data from lod folders. The LOD generation command will not regenerate existing LOD blocks: they need to be removed from your worldspace's LOD folder in order to be regenerated. If you have changed the number of cells in your worldspace (by expanding it) forgetting to remove these files will likely result in LOD errors in your mod. (This is true for terrain meshes, but it is uncertain in regards to other types of LOD generation. Requires additional testing.)
• LOD information is stored in the following folders:
  • data\meshes\landscape\lod\'your world space'\ which includes all terrain meshes and up to two subfolders: blocks and trees for LOD objects and LOD trees, respectively
  • data\textures\landscape\lod\'your world space'\ which contains diffuse, diffusegenerated (if you have not converted it to the diffuse folder), normals and possibly blocks for LOD objects
  • data\LODSettings (remove the file for your worldspace only)
  • source\textures TG\landscape\lod\'your world space'\ which contains all of the generated textures for terrain, objects, and trees which you should have moved or copied to your textures folder during the first pass. The source directory is located in your main Bethesda Softworks directory.