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Asset LODs

This doc will give a run-down of how we name and handle LODs at CAVE.

Introduction

LODs (Level of Detail) are a great way of managing the complexity of an asset. If you are new to LODs, check out the following Wikipedia page: Level of detail, which has plenty of good info on what LODs are, how they are used and how they came about.

When creating assets, a discussion should take place with the supervisor to decide which LODs should be created as not all assets will require multiple levels of detail. Primarily,  we’ll be using LODs for two purposes:

  1. We will switch the model LOD depending on the assets proximity to the camera (for example, an asset closer to the camera will require a higher level of subdivision and detail).
  2. Allow artists to work with LODs at a lower resolution for better performance (for example, an animator will want to work with a LOD that allows for real-time playback).

LODs Breakdown

It is recommended that the highest resolution LOD (LOD0) is first established and then from that LOD, lower resolution meshes can be generated. Lower resolution LODs should retain the naming and the hierarchy that has been defined in LOD0. This will ensure there is less issues when switching LODs, especially when it comes to other departments that pick up the model, such as rigging.

At CAVE, the way we are managing LODs are as follows, which is similar to how the Games industry approaches LODs:

  • LOD0: Highest resolution render mesh
  • LOD1: High resolution render mesh
  • LOD2: Mid resolution asset
  • LOD3: Background asset
  • LOD4: Crowd asset
  • LOD5: Proxy geo

Although the notes below refer to modelling, we will also use the same LOD numbering system for rigging and textures where required. For example, a basic control rig will be LOD2 or LOD1 and the rig will all the bells and whistles will be pushed to LOD0. As we push more assets through the pipeline and test things, we’ll start to define this more clearly.

Please note that scan/LIDAR data will be published as a seperate file to retopologised mesh. More details on this will follow soon.

LODs in Detail

Here we will break down each LOD to give you a clearer idea on how to approach your assets:

LOD0

This LOD represents our highest resolution render mesh. This LOD will be used for Medium Close-ups, Close-ups and Extreme Close-ups. At this level, wrinkles will need to be modelled into the topology of the model.

Additional detail will be added via normal and displacment maps.

LOD1

LOD1 should be suitable for Medium Long Shots and Medium Shots. This LOD is usually LOD0 before LOD0 has been subdivided and the wrinkle lines have been modelled in. Hopefully that makes some sense 😉

Additional detail can be added to this LOD via normal and displacement maps.

LOD2

This LOD should be suitable for Full Shots and support the full asset being viewed on screen. If creating a hard surface asset for this LOD, bevelled edges (or creases) may be required.

Additional detail can be added to this LOD via normal and displacement maps.

LOD3

This LOD should be suitable for Long Shots and Wide Shots. Bevelled edges (and creases) may not be required. The geometry should be usable for projection work.

Additional detail could be added to this LOD via normal and displacement maps but may not be required.

LOD4

Models at this LOD will primarily be used as crowd agents. This LOD should support Extreme Wide Shots. Bevelled edges (and creases) will not be required at this level.

Additional detail could be added to this LOD via normal maps but may not be required.

LOD5

This LOD will primarily be used as proxy geometry allowing the artist to have a lighter 3d scene. Very rarely will this model be rendered. This LOD will also be used by the rigging department to create calamari geo.

Useful Links

The following links are mainly for your reference and to give you an idea of how other companies approach and tackle LODs:

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