I have a tile based board game where units move in 3D space on a 2D isometric view. When calculating attack tiles for a unit, how do I verify that they aren't shooting through a wall or a level too high for them see. I need quickly verify a lot of these attack tiles are within a unit's range of sight (about 20). What's the fastest way I can verify line of sight with the x, y, and z axis?

Somebody posted a similar question here, but it covers 2D sight calculation instead of 3D (making the answer very different).

I have a tile based board game where units move in 3D space on a 2D isometric view. When calculating attack tiles for a unit, how do I verify that they aren't shooting through a wall or a level too high for them see. I need quickly verify a lot of these attack tiles are within a unit's range of sight (about 20). What's the fastest way I can verify line of sight with the x, y, and z axis?

Somebody posted a similar question here, but it covers 2D sight calculation instead of 3D (making the answer very different).