if (length_geometry && length!=0.0 && parent!=null) {
//model.isShowing.set(false,edu.cmu.cs.stage3.util.HowMuch.INSTANCE);
Model unit_cube = new Model();
geom = buildBoneGeometry(.04,length);//buildUnitCube();
unit_cube.addChild(geom);
unit_cube.geometry.set(geom);
unit_cube.isFirstClass.set(false);
unit_cube.name.set(model.name.getStringValue().concat("_bone"));
model.addChild(unit_cube);
model.parts.add(unit_cube);