anchor.diff:          let heightScalar = 0.5f
           let heightMax = 16.0f * heightScalar
           let position = v3Zero
  -        let size = v3 (single tileMapWidth) (heightMax * 2.0f) (single tileMapHeight)
  -        let bounds = box3 position size
  +        let bounds = box3 position (v3 (single tileMapWidth) (heightMax * 2.0f) (single tileMapHeight))
   
           // make positions array
           let positions = Array.zeroCreate<Vector3> (tileMapWidth * tileMapHeight * 6)
  
positive.code:             let untraversableHeightLayer = tileMap.Layers.["UntraversableHeight"] :?> TmxLayer
              let traversableLayer = tileMap.Layers.["Traversable"] :?> TmxLayer
              let traversableHeightLayer = tileMap.Layers.["TraversableHeight"] :?> TmxLayer
              let (untraversableSurfaceDescriptor, _, _) = createFieldSurfaceDescriptorAndSizeAndVertexMap tileMap.Width tileMap.Height tileSets untraversableLayer untraversableHeightLayer
              let untraversableSurfaceDescriptor = { untraversableSurfaceDescriptor with Roughness = 0.1f }
              let (traversableSurfaceDescriptor, traversableSize, traversableVertexMap) = createFieldSurfaceDescriptorAndSizeAndVertexMap tileMap.Width tileMap.Height tileSets traversableLayer traversableHeightLayer
              let surfaceDescriptors = [|untraversableSurfaceDescriptor; traversableSurfaceDescriptor|]
              let bounds = let bounds = untraversableSurfaceDescriptor.Bounds in bounds.Combine traversableSurfaceDescriptor.Bounds
              World.enqueueRenderMessage3d (CreateUserDefinedStaticModelMessage (surfaceDescriptors, bounds, fieldModelAssetTag)) world
              CachedDescriptors.Add (fieldModelAssetTag, (traversableSize, traversableVertexMap))
              (fieldModelAssetTag, traversableSize, traversableVertexMap)
          | (true, (traversableSize, traversableVertexMap)) -> (fieldModelAssetTag, traversableSize, traversableVertexMap)
  
      let tryGetVertices index field world =
          let (_, _, vertexMap) = getFieldStaticModelAndSizeAndVertexMap field world
          match Map.tryFind index vertexMap with
          | Some index -> Some index
          | None -> None
  
  
negative.code:                  Content.skyBox Gen.name
                      [Entity.CubeMap == Assets.Default.SkyBoxMap]
                   Content.entity<CharacterDispatcher> Gen.name
                      [Entity.Position == v3 0.0f 2.5f 0.0f]]]]
  
      override this.Register (game, world) =
          let world = base.Register (game, world)
  