Wow, big question - but the short answer is that the whole project is driven by establishing the upright rounds pole positions and translating this upwards to know how this works with the gradient, tree and branches above - this is where it can get very exciting. With treehouses, you don't get to clear and flatten the site before starting work, the whole 'wow-factor' is working [in 3D] with the natural curves of the gradient and random tree positions. In terms of delivering a project, we have to know that all the heights, dimensions and designs work - you can see here that everything needs to work in order to bring the Rope Bridge out at 'ground-level' from the highest treehouse deck.