The first is how to make hole in a terrain. For example I want to fall through my terrain. I've made that by painting absolutely invisible material in the terrain editor, but result was not good enough. Maybe there is anoter solution?

Second is why do a procedural terrain do not cast shadow on himself? Below there is 2 pictures. On the first picture terrain is standart, on the second  - procedural.

Thanks in advance!

You haven't changed anything in the lighting? Are both terrains exactly the same size?

To make a hole in a terrain, you can use the Raise brush, and tick the "Invert" button.

Nope. The only thing I've done was converting my terrain to standart. Maybe there is 1-2 frame difference in animation between two pictures.

I want to create "true" hole in the terrain, not only deepening. Somehow trim hole in a terrain.

if you want to cut a hole out of the bottom of the terrain, then you should use a boolean subtract on the terrain.

You can use a boolean operation as Rich_Potter suggests, but you can also dig with a brush, then clip from below, until the hole appears.

A brush seems more appropriate than a boolean operation, since there might be a material issue, and booleans take a tad more time to render. You can use one of the terrain brushes from the terrain brushes collections, and play with falloff to get a smooth edge.

too true, do what lars and bruno say :D

Ok, thank you, guys!