Is there a tutorial/demo for doing a "planet zoom"?

For example, starting with a sphere with a world texture, zooming in to a more detailed texture of a country, and so on, until you get to a mesh with some terrain and buildings on it? (We'll assume that there is only one particular place that you can zoom in on, not the whole planet!)

Similarly, starting with a leaf mesh, zooming in to a particular part and blending in to a mesh of some leaf hairs.

My first thoughts are you'd have several meshes of different scales and alpha blend them together as you zoom in?

 

Seems similar to how trees in Unity work actually.

 

That called LOD

 

Kind of. But If I am zooming into just say England, I don't need a mesh of the whole of the planet at that scale... will LOD work with this? Can LOD work from a planet size down to a person size?

I would like to see a video of this.

How do you do this in Unity?

 

You can just put the England mesh on the planet, where it should be, with LOD Group component. When at planet scale, England will look like a part of the planet. When you scale up, the England mesh will switch to higher LOD, while the planet will stay the same because it doesn't have higher LOD mesh.
Then you can just put a London mesh where it should be on the England mesh, with LOD Group component too, when you zoom into London, England doesn't have higher LOD level, but London will.

 

You can do that by overlaying flat images with blending on top of the planet, only for blend layers to dissolve into final mesh.

Given that earth is way bigger than recommended map size, using LODs may not work and you will most likely have to cheat.