Creating the models

Everything that you see on the computer screen when viewing 3-dimensional graphics is a collection of triangles, on the surfaces of which are colours.

What looks round is actually a set of flat surfaces, cunningly arranged to give the illusion of steady change.

As an example, Elvington's platform, shown here from the footplate of an arriving train, was built on a curve.

Putting a straight platform in this position would look wrong, because the eye would notice the variation in the gap between the rail and the platform edge.

Putting a straight piece of track in for the short length of the platform is one way round the problem, but it would not have the flowing look that the actual railway had.

Another view, showing the coach alongside the platform.

The straight step of the coach shows that the platform edge is curved. The coach itself is as long as the platform.

This shot shows how little is needed in MSTS to produce quite believable images. The track is an additional item, UK Finescale, developed by Tim Booth and available for download from the UKTrainsim site.

The locomotive is by Paul gausden.

The coach is by Jeff Layfield.

The curved platform was made using the outer edge of the sleepers of the curved piece of track as a template, so that the distance between the white edging and the outer rail will appear visually to be constant.

But that curve is actually a series of straight lines, as the shots of the untextured model in Sketchup show.

The underneath view shows the straight green axis of Sketchup, and the 5 sets of straight sections which go together to create the illusion of a curve.

Note that the platform surface is also composed of a set of sections joined together, but it was possible to erase the join lines in Sketchup because there was no actual change in direction of the surface at the position of the join line, unlike the side walls.

The textures which were applied to the side walls hid the vertical lines in the finished model.

The decision that has to be made when creating such a model is "how many straight sections must I use?" It is tempting to fall into the superdetailing trap and decide that you will model every brick: since the curved platform face is made up from hundreds of straight nine-inch bricks, then make the curve from a series of 9-inch long straights. This will, apart from being terribly fiddly to do, result in a rather large model, in terms of triangles which the graphics card has to draw and cover with textures. At the opposite end of the detailing spectrum is the simplistic approach: use two sections and effectively model the platform as a Vee. While this might simplify the job of the graphics card, it wouldn't create such an effective ilusion. I chose to use five sections, each ten feet long. Using an odd number means that there is no transition form one straight section to the next straight section at the centre of the model, which is where the eye will instinctively go to when first seeing the picture.