Select "Create Room-Structure-Sunken Column" in the left list and drag it into the scene. Then you can modify the length, width and depth of the sunken area. To replace the material of the sunken, please use the material brush from the top toolbar to extract material from other finishes and apply it to the interior surfaces of the sunken ground.
How do I sunk my area more than 100mm which is the maximum allowed. My area sunk with 1 meter, with steps going down. but it is part of the ground floor.
