Making the model more detailed.

I think he had a concept of it being essentially a flying hotel. When we first photographed the Enterprise in its very early stages, the large model, there were only running lights on it. There were no lights within the dome - the bridge, up on top. That was opaque at that time. We gradually got lights inside, and put lights around the rim, but lit from the inside.

It was made out of fibreglass and it would get very hot when we kept the lights on, so we found that we had only a very short period of time to leave the lights on to get them up to the right level and have them on. And particularly up in the dome and the bridge.