# Unity Bounding Volume Heirachy ![BVH GIF](https://camo.githubusercontent.com/91466741b927ac18c235192227dc11d31e3b759f052f0b641306a15b1fda3609/68747470733a2f2f6d656469612e67697068792e636f6d2f6d656469612f5a616f6d4c7479626f5a5370397a6c3657592f67697068792e676966) Dynamic Unity 3d BVH - 3d Bounding Volume Hierarchy. Modified from David Jeske's [SimpleScene](https://github.com/jeske/SimpleScene/tree/master/SimpleScene/Util/ssBVH) ### About This is a 3d Bounding Volume Hiearchy implementation for Unity in C#. It is used for sorting objects that occupy volume and answering geometric queries about them; such as ray, box, and sphere intersection. It includes an efficient algorithm for incrementally re-optimizing the BVH when contained objects move. This variation works in Unity and supports GameObjects. For more information about what a BVH is, and about how to use this code, see David's CodeProject article: * [Dynamic Bounding Volume Hierarchy in C#](https://www.codeproject.com/Articles/832957/Dynamic-Bounding-Volume-Hiearchy-in-Csharp)

BVH.cs	The root interface to the BVH. Call RenderDebug() to render the debug bounds using DrawMeshInstanced.
BVHNode.cs	The code for managing, traversing, and optimizing the BVH
BVHGameObjectAdaptor.cs	A IBVHNodeAdaptor with GameObject integration.
BVHSphereAdaptor.cs	An example IBVHNodeAdaptor for spheres in the BVH.
IBVHNodeAdaptor.cs	Base interface for any BVHNodeAdaptor. Implement this to create a new adaptor.

### Notable Modifications - Supports GameObjects through a custom implementation of IBVHNodeAdapter (BVHGameObjectAdapter). Uses child renderers bounds to calculate bounds. Could be easily swapped out for any other bounds calculation. See BVHGameObjectAdaptor.GetBounds. - BVHHelper provides a radial node traversal test to be used with Traverse(). - Code has been refactored to be _closer_ to the .NET naming conventions. - Includes some tests that can be used as a starting reference. ### References * ["Fast, Effective BVH Updates for Animated Scenes" (Kopta, Ize, Spjut, Brunvand, David, Kensler)](https://github.com/jeske/SimpleScene/raw/master/SimpleScene/Util/ssBVH/docs/BVH_fast_effective_updates_for_animated_scenes.pdf) * [Space Partitioning: Octree vs. BVH](http://thomasdiewald.com/blog/?p=1488) * [Dynamic Bounding Volume Hiearchy in C#](https://www.codeproject.com/Articles/832957/Dynamic-Bounding-Volume-Hiearchy-in-Csharp) * [SimpleScene](https://github.com/jeske/SimpleScene/tree/master/SimpleScene/Util/ssBVH)