Ultimately depends on what format(s) you want to support in your final engine. Since no texture or material properties and its just geometry you want to define, Wavefront OBJ is pretty straight forward to write importers for and supported by many modellers (modern day ones).

https://en.wikipedia.org/wiki/Wavefront_.obj_file

Not used many DOS modellers apart from some anemic AutoCAD. Probably more for the lulz since not many will support mouse, and the ones that do probably won't give you much precision so you will find yourself dropping down into a command based "plot line x1 y1 to x2 y2" command style scripting to model o.0.

I would suggest model in what ever program you are familiar with (wings3D is lightweight and free, or blender heavy-weight free). And output to odskool 'low-poly count as possible' wavefront obj file.

POVray, and I suspect Rend386, are renderers not modellers so won't be much help.

Blender can be used for low poly art without much issue. It also has vertex painting tools so if you wanted to do things the FF7 PSX way you could (model format/engine permitting)

I don't recommend reading .blend files themselves though.

xjas wrote:

Let's say I want to make some 3D models for playing with on an unspecified 3D engine that I may or may not get around to writing in the future. We're talking low-poly, flat shaded, colored, no textures. The engine would target DOS or some other suitable oldschool platform.

What should I make them in?

3D Studio DOS?

I remember in highschool, a friend of mine used 3D Studio DOS to make various 3D models that fit your description. He never took a course, and it was 1993, long before you can easily find free tutorials on the internet. So he was learning by himself, yet he managed to make some cool, Japanese super robot animations, so perhaps 3D Studio DOS is pretty easy to learn.

Never got the chance to learn to use it myself though; I was busy composing tracker music at that time.

I would definitely recommend Blender. It supports exporting to .obj format and it runs on modern machines and it has good interface. Oh and it is free.

made me think of the dxf file format