ViveNavMesh will still try to render a mesh with no material.

[AlpyneDreams]

ViveNavMesh will still try to draw its mesh even if GroundMaterial is null, which crashes the engine.

[Flafla2]

This is obviously an oversight, but I believe the engine crash is only present in Unity beta version 5.4b18 and earlier. I reported the issue to Unity a few days ago (pertaining to the mesh being null, not the material, but materials were also effected. See 5bd718c) and they fixed it in 5.4b19. I'll add a quick null check to ViveNavMesh for earlier betas of course.

[Flafla2]

Fixed in version 2.0.0.