You might like to have a look at this recent thread, where very similar two-pole tents are discussed.
The angled-to-the-ground ends are great for wind shedding, but, as others have pointed out, not so good for internal volume, hence the truncated ends of my effort.
As for the waterproof groundsheet tub, think about how you might build & peg out those acute angled ends. Go and look at a bunch of tent designs and see if you can figure out why no-one does it.
Think about the integrated flysheet, and look at other tents, and ask yourself why there's usually a gap between the flysheet and the tent inner.
Since it looks like you're using SketchUp, you can always make a 'body model' (even if it's only a 'block of foam' like Samuel suggests, or get a SketchUp body model from somewhere, like David Drake has). This body model will help you to identify collisions, and space/volume problems. I think there are SketchUp plug-ins that will create flat patterns from your drawing, which you could print out and make paper models; that's what I do (not with a plug-in, though; I wrote some code about 16 years ago to do something similar, and I keep tweaking that...).
> I know it is just an idea but sometimes these things have a way of growing into something so much more.....like an obsession, or an unhealthy habit.
Or a career...
Designing things is great fun. I've been doing it since I was four, and have been doing it as a career, all my life. I still get incredibly excited when I'm designing stuff (even at work sometimes...), and get a real sense of achievement. That's why I've not told you how your design should be, but, hopefully, have given you pointers as to how to go about looking at, and solving the problems. If you just want to build something, then being told is fine. If you want to design things, it spoils the fun...