The Babylon Project was our last best hope for peace. It failed. In the year of the Shadow War, it became something greater, our last best hope for victory.
I am looking for software that works with Linux, and is easy to learn & use. I want to have 3 dimensional line drawings of ships for a science fiction game. I would like something that would be consistent when the ships are viewed from different angles, but only showing the lines for the facing sides, not the lines on the non-facing portion.
Longer answer: Blender 3D will do what you want, and a billion other things. The trick is to learn what you need without being overwhelmed by all other features in the application. There are many tutorials, and many good articles on how to achieve specific effects, but you probably need to spend a weeknight or two learning the basics before you can use it for anything.
You can probably install it directly on your Linux computer using apt-get or yum or whatever the package manager on your favorite distribution is called. Latest version and more info is here: http://www.blender.org/
I was curious and did a quick search on how to render things like solid wireframes the way you describe and found this video plus instructions. Looks like the important thing is just to find and enable the Wire button in the render settings: http://www.katsbits.com/tutorials/video/render-wireframe.php
Good thing is that Blender has so many users there are tutorials on everything. Only problem is that some tutorials are for old versions and might require some tweaking to work on the latest version.
Google has had SketchUp. Guess they sold it last year. The basic program is free. A comic I read online, Spacetrawler, uses it for different backgrounds, ships and interiors of ships. He uses them as reference. You can check the post where he has an example here.
Not as robust as Blender, but also does 3D rendering.