For this project I was lucky enough to find some floor plans online. At the time, the Google Earth terrain in Los Angeles was very wonky and it would have been hard to get a clear "footprint" of the building. The actual hilltop site has been leveled off since 1930 or thereabouts, but our Google Earth hilltop was very rounded like... a hill (now the GE topographical data is very high resolution and the hill is manicured into a flat lawn, just like in real life, but not at the time the model was made).
Model was built right on top of real floor plans
As the model progressed, the original floor plan disappeared bit-by-bit, to be replaced with glorious photo textures which add so much realism to the final product. One thing had me stumped-- how was I to texture the three large domes on the building? In real life they were copper with a beautiful patina and other signs of aging and character. (One houses the sun scope; another the telescope; and the biggest of all looms over top the planetarium). How would I take a photo of a curved dome and apply it to a bunch of flat surfaces (because, if you don't know, everything in SketchUp is flat-- even "curves" are really just a bunch of flat chips put together).
My solution was to create a completely false texture, patina and all, and project it downward over the domes. Imagine breaking an egg and watching it run down the sides of someone's head... or shining a flash light down on a ball and watching its light touch all parts of the curve right down the sides... basically that's the idea. Here we can see the texture that I created in an image editing program, and the way it was used to create a fairly realistic-looking aged copper dome in SketchUp:
My own flat painted texture on the left; finished 3D dome model on the right
The copper joints running around the dome were made simply by creating additional, horizontal bands of geometry and painting them with a flat dark brown color. But, this created a lot of excess polygons. I have some other solutions to copper dome-making that I want to try out. I'm actually re-doing the Observatory model, and what I have so far (thanks in part to much more accurate topographical data from GE) is about one-and-a half-thousand times better than this.
Plus, practice makes perfect. This was my first really complex model, and I did it within a couple months of ever having tried to use SketchUp. I was pretty proud of it and felt in part that I was making a little piece of history. I am anxious to see how the improved one will turn out...
EDIT: I had used SketchUp as early as a couple years prior to this, but I made this model within a few months of using SketchUp in earnest.