This function would be interesting and certainly faster than the current functions. Occlusions would be very useful for objects under water, on the clouds, etc..

You're right. Such a function will be added. - On second thought, it's already possible with the current region system. You can create a vertical region at any height.

Your right, it can be done with the current function. I´ll explain a little better. With the current function you will see if the object fits within the region of x, y, z. I proposed you use another function, but to only search through axis z, which would mean 77% faster and mostly concerned with seperating regions by height. I proposed this for the increased speed it would have allowed for. Although, as you have said, you can currently do this, however 77% slower because you are looking between x, y and z.

Don't worry, it is not slower. The x,y,z coordinates are not checked for every entity. Instead, the region affects the branches of ABT and BSP trees.

Ah, well, thanks for the reply, I thought it worked with coordinates.