Ok just wanted to mention that with sketch up you have to draw every board not just lines (unless you just want to play with possible dementions). I draw 2x4s as 2x4, 2x2s as 2x2 but when you go to build realize that lumber dementions are actually off by a little. You can refer to this table if needed http://en.wikipedia.org/wiki/Lumber#Dimensional_lumber. Mesh is very hard to draw so I just fudge the the fencing materials provided to represent what I will actually use.
It's not as bad as it sounds. I actually draw out "standard" dimension lumber & save them as components first. Then I just copy what board I need for the plan. Think of it as "virtual" building. This is how I figure out my materials list by how many "copies" of what board. As for mesh, there is a fill pattern that's pretty close that I use. I know it's not 'exact' but it does give me an idea of how it will look. If you can find a photo of the exact mesh you want to use, there is a way to create your own fill pattern based on a photo. That might be something to play with too.
And if it all sounds like too much, pencil & paper works just fine too.