You set the cube size with “initVolumeSizeInMeters” in the Options structure defined in ViewController.h
You can adjust the location of the cube from the variable “depthCameraPose” found in ViewController+OpenGL.mm
The SDK code sets the location of the cube relative to the scanner with:
GLKMatrix4 depthCameraPose = _slamState.initialDepthCameraPose;
You can change the location of the cube by doing this:
depthCameraPose = GLKMatrix4Translate(depthCameraPose, 0, 0, my_distance_value );
where my_distance_value is the distance from the scanner.