It is necessary to display cubes on the plane, their dimensions are given in mm. and their coordinates in mm. When I transmit this data to THREE, huge holes are obtained between the cubes, although they stand wall to wall, tell me how to convert the units correctly so that it looks like reality?

Link https://codepen.io/ybelyavsky/pen/rNJppMo

  const itemGeometry = new THREE.BoxGeometry(200, 200, 100); // mm.
  const itemMaterial = new THREE.MeshNormalMaterial({ color: 0xffffff }); 
  const mesh = new THREE.Mesh(itemGeometry, itemMaterial);
  
  // mm. from 0.0.0
  mesh.position.x = 0;
  mesh.position.y = 100;
  mesh.position.z = 200;

enter image description here