Weird Tears in terrain mesh in Render View only I used a LIDAR point cloud, imported it in meshlab, sampled (from 9 million points to about 1) and reconstructed a mesh for it, set normals, exported as OBJ, then imported it into Blender 2.76.
I have Cycles Rendering on, made a simple material in the node editor with just a Diffuse BDSF shader with a flat color and no roughness (0.1 roughness looks the same).
I get this wierd result:



This is in Render View

Material view looks fine.

What am I doing wrong?

Here is my .blend
The problem is caused by the fact that although the terrain origin is at (0,0,0), the real mesh is still very far from it.

So it seems you have to use a very large clipping range (1000000 in your case), which allows you to see objects, but reduces the depth precision. This is a known limitation of all softwares using OpenGL.

To fix it, you can:


Increase the start clipping.
Decrease the end clipping.


However, you may also have to scale the objects to see it again. (And, in your case, I would suggest you select the terrain then ShiftCtrlAltC > Origin to Geometry, to relocate the origin from afar. Then move them back to the world center.)