Some further work done on the ravine. As was suggested some further depth was added (and as it turns out we need the ravien floor) and the ravine mouth was openined up more. The next step will be to add some ledges and make the rock more jagged. But so far I think we're making steps in the right direction. I also give ends to the ravine as it would be surrounded by a seabed in the final production.
The sphere represents our fish. As can be seen this ravine is pretty large, which should give us plenty of time for the fish to travel upwards. It was suggested that there could be a sharp turn to encourage the fish to swim up but that proved slightly difficult to insert without tearing the lower sections of the ravine which would make moving the camera more difficult as we would have less space to work with.
To add ease to contruction and animation I have divided the ravine into three sections that can be switched on and off in the layer view depending on on what angle we need to look at. One for the left-hand side, one for the right-hand side and one for the floor. I suppose it also makes seeing the floor a little easier in the wireframe view. In theory these can all be stitched together for the final model. But for east there could be be a construction layer set and a final polygon set with all the lines connected. Currently the join between the rock and the ground looks rather artificial when smoothed out due to the sharp line. Being presumably sand or part of the rock shelf, it looks too neat.
Although thinking about it, the join could do with some unevenness to it anyway as it currently all joins on the same level which is unrealistic.