Cliffs / Ledges

Photogrammetry is excellent, but always keep modular design in mind I discovered, that is, the pieces must be able to be retrofitted into the landscape, not an easy task with semi-flat actors. Unless you can find a nice relatively uniform shelf of rock and earth in the world somewhere to use for photogrammetry, you'll have to model one by hand. The more I go along, the more I understand the importance of modular design, try to create things that can be used many times over with variation, this cannot be understated!

Trees via SpeedTree

At first SpeedTree is a pretty intimidating program, once I sort of got the hang of it I noticed that within just a few simple steps triangle count can skyrocket into the tens of thousands! But did some research and found that the target poly count should be around 8k to 15k for games, the first thing that came to my mind was the game The Witcher 3: Wild Hunt, those trees are so beautiful and high poly looking, how did they pull it off? I jumped into the game and spent some good time just studying the trees, at last I found the secret. Though they've taken optimization a step further than I have, I'm not far off. The secret is to optimize the heck out of the trunk and branches (low triangle count), and at the end of each branch place a generated mesh (much like the shape of a shovel head, or rooftop) that does not move (not camera facing billboards), then on the branch between the generated mesh and the trunk place centered camera facing cards to give the look of fullness! Brilliant. Here are the results (note: all textures were created by me except the pine needles, SpeedTree includes a nice pine needle texture and I didn't see the need to reinvent the wheel) -

Weighing in at just over 8k tris, a beautiful old oak tree:

And at just over 4k tris, a wonderful and tall pine tree:

Materials via Substance

Although it's better I find to use actual photos as a base for creating materials in Substance, I love to just jump in and whip up something I need if I don't have it. It's not always easy to do that, but there are multiple ways to achieve what you are looking for.

A nice wall or ceiling material, with scrapes of drywall compound and spatters of paint:

Wood paneling w/o knots:

Wooden rooftop shingles with parallax occlusion:

Cracked rock surface with water gathered in its crevasses: