Hi everyone. 
I’m pretty new to blender still, but having lots of fun learning it. Right now I’m following an online course and the current project is to design, model and render a robot.
I made a little police sentry type bot I thought up and have been toying around with different fun ways to render it. I have a few different color schemes, and the one I’m working on now is kind of a park ranger type color. My idea for him was to have him render on top of some images of forest or park scenery, and try and have him blend (hah) in. While I’m not going for a photorealistic scene by any means, I had just learned about Freestyle and thought it might look good with the robot.
Anyway, my first render was ok-ish, I placed him where I wanted him, fixed the lighting and Freestyle options, and I had to fake a shadow through Photoshop (very new with that also). My second render on the other hand (I have several park photos I’m gonna try and use) looks much better. For this one I made a rough model of the ground he was floating over, and I had the lighting make a ‘real’ shadow instead of my fakey Photoshop smudge. 
Here’s the second render, which turned out alright:
Well, on to the issue. I’m currently working on my third and last render for this bot version. I’ve got a similar setup. For this I created a plane as the ground and side “wall” to help with the shadow. At first the Freestyle contours were showing up on the planes despite being set to Shadows Only, but I solved that by adding them to a group and excluding that group from the Freestyle layer. First off, here’s what the planes look like (I included them just to show where they were placed roughly):
Now this is where the problem arises; in order to get the Freestyle layer to look good on my robot, I have to exclude the planes from the render. (That’s the only solution I’ve found so far) If I do so, the robot looks like this:
If I include the planes in the render, despite them not being included in Freestyle, the lines on the robot suddenly become transparent, and I can see the lines I shouldn’t see since the robot is opaque.
I haven’t worked out the lighting yet either as you may have noticed, but that’ll be after I solve this issue.
Now I’m hoping I can get some advice on this. I’m stumped; my only solutions currently are either to exclude the planes from the render, and getting the Freestyle look, or to include the planes and thus get good looking shadows, but no Freestyle.
Any help?
Higher samples seemed to give slightly better shadow definition so I went with 20.