Picking a material to make curved surfaces

I’m a high school student taking design classes at ACCD.
Every term we have to make a model of our final product, and I’m having troubles figuring out a material to make my monorail out of. (the project is monorail design)
My monorail will have curved surfaces on the side panel, so I’m wondering what kind of material I could make it out of.

I’ve heard and seen lots of models from previous terms that are made of yellow foam, but I’m hesitant on using it because:
a. It’s expensive (I heard)
b. Is getting good symmetry a problem?

I’ve been thinking of making cut outs out of foamcore and spacing them out and then covering it with something (maybe clay or something of that sort, but I’m low on time because of school and stuff <_<.

So are there any easy manipulable materials that I could use to create curved surfaces? (My design from the front view is like an “H” except the center line of the H is the passenger area and the | | on the outside are the outer panels,which will be curved)

I’m a newbie to yellow foam and curved surfaces, so any advice is appreciated. (My model last term was all foamcore because it didnt have any weird curves and stuff)

First, ignore that previous solicitation post. Obviously if you’re in high school you aren’t going to ship your model to China to be made.

Second, blue foam is cheap. Carving w/ symmetry could be tough, but no tougher than anything else really. If you want to have a fluid shape a carved foam model is the way to go. You can cut it, sand it, glue it, you name it. It’s the standard really. Run over to Home Depot and grab a chunk and go to town sanding, cutting and gluing. I think you’ll find it’s what you’re looking for.

It’s the standard really. Run over to Home Depot and grab a chunk and go to town sanding, cutting and gluing. I think you’ll find it’s what you’re looking for.

And don’t forget to buy a few of those paper particle masks … and use them :wink: Foam is great fun to work with but breathing in the dust isn’t.

As far as keeping your model symmetric is concerned, it’s a matter of establishing some control points to measure from. A centerline, divided into stations (at say 1 inch increments), from which you measure perpendicular (right/left & up/down) to control the surfaces. Do this in both planes and you get your 3D form pretty accurately. They’re called sections and lifts. Think of a section as a slice of bread (a vertical cut), and a lift as a layer of cake (a horizontal cut).

In this drawing of a ship, the horizontal lines represent the lifts, and the vertical lines represent the stations (where the sections are located). In the “top view” the oddly shaped lines represent the shape at the water line of each lift. As such, they are termed “waterlines”, and provide the builder with a third set of dimensions for added control. Basically a lift is the same as a section … just cut a different direction. They’re named differently so that it is easier to understand what is being talked about. In the view of the sections at the right, note that the sections from the bow to the center of the ship are on the right side of the vertical centerline, and the sections from center back to the stern are on the left side of the centerline. Why? Since the shapes are symmetric about the centerline, it take less space than drawing a full section.

Additional parallel lines, are termed butt lines; as in this drawing of a Chinook helicopter. They add yet another degree of control when developing shapes. Note: the sections are not shown in this drawing but their stations are. Also note the the very tip of the nose of the helicopter does not begin at 0.00 (zero); that is because most aircraft are modified at some point and the practice leaves a bit of wiggle room.

The sections and lifts, when combined with the centerline distances are enough to build your model. I hope this isn’t too confusing, “easier” comes with time and experience…

That’s a really nice shipbuilding reference you found! The chinook is cool, too but the ship is way cooler!

just ran across this. Very nice project documentation of a semi-truck design. Might give you some ideas.

Ah, Thanks for all the references and tips!
I’m still debating whether or not to use foam;

Are both yellow and blue foam very hard/solid?
I read some articles online that suggest cutting it with something with heat.

It can be cut very easily with a hot wire foam cutter as shown here: Homemade CNC hot wire cutting machine - YouTube but you can cut it with a regular wood saw then send it back. Its very easy to sand and not very hard so watch you don’t dent it after you have got don to your finished surface.