I’m doing a very simple 2D, plan view landscape design, and have some basic rectangle shapes. I select a box and then try to use the soften edges feature. A dialog box appears but nothing is highlighted/it’s all faded and I can’t select anything. When I right click on an edge on a rectangle I can select “smooth” but nothing seems to change. When I print it the lines are all kind of thick and jagged. How do you get tiny, slick, smooth lines?
Soften edges is the wrong tool here. You should have a look at the edge style settings first and play with the export resolution of your image (button in the export dialog) to get finer lines.
Basically, what Sketchup prints is what you see on your screen. To make lines look smoother, you can try the antialiasing options available in the Window menu>Preferences>OpenGL dialog. Also, if your printout has only linework and smooth colours (no textures or shadows needed) you can try the “Use high-accuracy HLR” print quality option that sends vector lines instead of raster images to the printer (on the Mac it is called more intuitively “Vector printing”).