HDG Potential Visible Set World Streaming System

How It Works

The world is divided into overlapping visibility regions called Sectors.

Each sector contains all of the game objects which overlap that Sector. Objects can be contained in multiple sectors, but the engine keeps track and will only load them once.

During the build process, the tool creates a scene for each Sector. These scenes are loaded additively at runtime.

Build process:

1. You supply a list of scenes to load and process.

2. Each scene is opened and its contents moved into a pool of all objects.

3. Each object is broken down into multiple objects following simple rules:

a. If the object is not marked static, store it as a whole object.

b. If the object is static, break its children down into separate objects.

c. If the object has certain specific components, like a LODGroup, do not break it down - doing so would break the special component.

This is applied recursively to 'flatten' the hierarchy.

4. Each object is assigned an ID.

5. Each object is assigned to one or more sectors.

6. A scene is created for each sector.

7. These scenes are added to your scene list in player settings.

At runtime:

1. Starting from the camera's current position, determine which sectors are visible.

2. Load those sectors.

3. Unload anything that's no longer visible.

Workflow

Step 1 — Build Your World

Create your world normally using scenes, prefabs, terrain, and gameplay objects.

The system works with:

* Single scenes

* Multi-scene setups

* Additive scene loading workflows

Step 2 — Place Sectors

Add Sector volumes throughout the world.

Sectors should:

* Cover all traversable areas

* Contain (or at least overlap) every object that should ever be loaded at runtime.

* Objects that are not in any sector will be placed in a scene labelled -1 so that you can identify them and fix it.

* Slightly overlap neighboring sectors

* Match logical spaces where possible

Proper overlap is important so the system can determine transitions correctly.

Portals are automatically placed wherever sectors overlap during the build process.

Optional door components can dynamically enable or disable portals at runtime.

Step 3 — Mark Important Objects

Give important objects an ImportantObject component and set the partition they should be placed in.

These objects will be assigned to a special scene that is always loaded.

Step 4 — Build the PVS

Create a game object and give it a PVSEngine component.

Configure your list of scenes to be included by the PVS Engine.

Click full rebuild to generate the streaming scenes.