Hi Robert, there are a few tutorials linked under the page Mike gave above, you'll definitely want to look through those to get some more background.

I'm expecting to be working on some more tutorial and documentation information pretty soon, once the software is completely finished for V1, it won't be much longer.

One general tip - you don't normally create a complex shape all just in one single command, you normally build it up in pieces using a few different steps.

So the first step for your train could be to punch out your outline to give it some depth, kind of like a cookie-cutter type method. You can do that using the "Extrude" tool - find it under Construct / Extrude.

Since your shape is on the centerline of what you want, you'll probably want to check the "Both sides" option. Options for a command appear in the upper-right area of the MoI window. When "Both sides" is enabled, the extrusion uses your curve as a center line and the shape comes out from either side of it.

You were asking about Loft - in MoI the term Loft means to create a surface through several cross-sections. If you look at the icon for Construct / Loft, you can see 3 hoops and then the resulting lofted surface through those 3 hoops. So that isn't quite what you want for your case because you don't have multiple sections in this case.

After you have extruded your shape you will have the basic start of your train body. But it will look like a flat block. The next step that you can do is what Pilou was showing above - draw another curve tracing from the front view, and then you can use a boolean intersection to carve away portions of your initial block to refine it a little bit. You can then try to use fillets to round off some of the sharp edges.

If you want to get more control over making a smoother shape, you will probably need a different approach where you build sort of smaller sections of the train using surfacing commands, such as loft or sweeps. That will give you a lot more control over creating more free-form and less blocky surfaces, but it is a more difficult route as well. I'd recommend sticking with extrusions, booleans, and fillets for a while and experiment to see what types of shapes you can do with those.

- Michael