...
temple = new THREE.Group();
temple.add(plinth);
temple.add(ramp);
...
temple.castShadow = true;
temple.receiveShadow = true;
It seems that .castShadow and .receiveShadow are not properties of a Group despite
a statement somewhere that the properties of Groups are the same as those of Objects.
Am I correct here? And do I have to use Object and or .merge?