| x | Start X position of the dirty heightmap region. |
| y | Start Y position of the dirty heightmap region. |
| width | Width of the the dirty heightmap region. |
| height | Width of the the dirty heightmap region. |
Triggers an update to integrate modifications done to the heightmap outside of unity.
Invoke this whenever custom custom terrain heightmap paint tools modify the heightmap to let Unity integrate the changes (update collision, physics, etc ).