how to do rays trough stone fissure Hello guys I want to simulate a morning sun shining trough this stone gap like seen in the pictures below. It would help me extremely when you could explain it rough how i could achieve smth like on the first ref image. 

Best regards Marc!
The rays in that image are actually most likely diffraction spikes caused by the aperture in the lens. To simulate that, you might try using the glare node:





Note that it helps if you have a very bright light source for the glare node to pick up on. Sun lamps are pretty good for this, but won't show up in the render directly. In the above example I made a refractive plane for the sun lamp's light to pass through, allowing it to be seen by the camera.