Version: 2020.1
Upgrading to Unity 2020.2(alpha)
Upgrading to Unity 2019 LTS

Upgrading to Unity 2020.1

This page lists changes in the Unity 2020.1 version which might affect existing projects when you upgrade from a 2019 version to 2020.1.

All Mesh vertices are transformed for better UV unwrapping

Unity might change the MeshThe main graphics primitive of Unity. Meshes make up a large part of your 3D worlds. Unity supports triangulated or Quadrangulated polygon meshes. Nurbs, Nurms, Subdiv surfaces must be converted to polygons. More info
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UVs of 3D objectsA 3D GameObject such as a cube, terrain or ragdoll. More info
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you import to a project.

Unity transforms the positions of all imported Mesh vertices to scale in Unity units automatically.

From Unity 2020.1, Unity generates lightmap UVs using the transformed Mesh vertices, if you’ve enabled Generate LightmapA pre-rendered texture that contains the effects of light sources on static objects in the scene. Lightmaps are overlaid on top of scene geometry to create the effect of lighting. More info
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UVs
. Previous to Unity 2020.1, Unity generated lightmap UV maps using the original imported Mesh vertex positions, before the automatic position transformation.

UVs generated after the vertex transformation are more accurate to the original shape and scale of your imported object.

All Asset bundle hashes are different so all bundles are built

From Unity 2020.1, Unity generates a different hash for all asset bundles in your project. This ensures all bundles are built, including the ones with the same content but with different loadable paths.

The multiplayer HLAPI package is not automatically installed in project upgrades

From Unity 2020.1, install the multiplayer HLAPI package from the Package Manager if the project you’re upgrading has scriptsA piece of code that allows you to create your own Components, trigger game events, modify Component properties over time and respond to user input in any way you like. More info
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that use the multiplayer HLAPI.

From Unity 2019.1 to 2019.4, Unity automatically installed the multiplayer HLAPI package when you upgraded a project created in Unity 2018.4 or earlier.

Improved LOD baking with the Progressive Lightmapper

Unity’s Progressive Lightmapper consists of the CPU and GPU lightmappersA tool in Unity that bakes lightmaps according to the arrangement of lights and geometry in your scene. More info
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.

From Unity 2020.1, the GPU lightmapper supports level of detail (LOD) baking.

The CPU lightmapper uses the same baking algorithm and this allows Unity to fully use all available CPU cores for faster baking times in ScenesA Scene contains the environments and menus of your game. Think of each unique Scene file as a unique level. In each Scene, you place your environments, obstacles, and decorations, essentially designing and building your game in pieces. More info
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with LODThe Level Of Detail (LOD) technique is an optimization that reduces the number of triangles that Unity has to render for a GameObject when its distance from the Camera increases. Each LOD level has either a Mesh with a Mesh Renderer component (Mesh LOD level) or a Billboard asset with a Billboard Renderer component (Billboard LOD level). Typically a single GameObject has three or four Mesh LOD levels and one optional Billboard LOD level to represent the same GameObject with decreasing detail in the geometry. More info
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values above 0.

To upgrade the LOD in your Scene, clear the baked lightmap and then regenerate it. To do this:

  1. In the Unity Editor, Open Window > Rendering > Lighting Settings.
  2. In Debug Settings, click the drop-down menu on the Generate Lighting button, then click Clear Baked Data.
  3. Click Generate Lighting.
Upgrading to Unity 2020.2(alpha)
Upgrading to Unity 2019 LTS