Black triangles on water :(

[TheElectroKangaroo]

Sometimes when I render a scene with only water and sky, black triangles appear on the preview render and (to a lesser extent) on the fullsize render too. This is what the preview looks like: http://sta.sh/0eduiked9h5

Any idea what could be causing this?

[Oshyan]

Hmm, it's been a long time since I've seen anything like that, not sure what would be causing it. Perhaps you could share the TGW (attach it to a reply here)?

- Oshyan

[engineer]

Yeah, that's something I noticed a long time ago...
If I remember right, the triangles occur if the terrain below the water surface has large displacements (peaks mostly).
Smoothening the terrain below water helped a lot.

But as said: years ago... and maybe my memory is wrong on that...