Workflow for modelling a real landscape

Hi all,

I’m looking for some opinions on the best way to tackle this project. Bear in mind I’m fairly new to Blender and 3D software in general.

Basically I need to model an environment in pretty high detail - about 2km x 2km squared. Beyond that 2km x 2km area I will have more landscape but it will be lower detail since the camera will never go there.

I have 5 metre contour data in the form of a DEM, which I then brought into Blender as a 16bit tiff and used the greyscale values along with the displace modifier to create the terrain. So far that system is working pretty well for me. However, there are a few problems I can’t get my head around:

  • I would like to increase the detail of this terrain beyond the 5 metre data so that it looks realistic when the camera is at ground level. No, there is no higher resolution data for that area available unfortunately. So I have to manipulate the ground manually. I think that the best way to do that would be to overlay the satellite imagery (pretty high res) of the area and use that as a guide to add extra bumps, paths, cliffs, streams etc. via sculpting. The problem with this is I cannot see the texture while sculpting which makes it pretty hard to do. I thought about actuall y not sculpting in Blender at all, and instead artificially increase the resolution of the DEM in photoshop, then manipulating the DEM there before bringing it into Blender. However I think that I will be working even more blindly than just sculpting in Blender. Can anyone can think of a smarter way to do this?
  • This brings me to my next problem - to add a high level of detail to a 2km x 2km area, I have to have a very high res mesh which brings a lot of performance problems. I thought about splitting the area up into say 250m x 250m sections. But I think this will bring a lot of problems when I need to then stitch together sections at the end. Would anyone recommend keeping one big mesh or splitting it up into multiple small ones?
  • Related to the previous, to get good detail on the texture for my ground I have to use a very large texture file to get high detail ground (currently using an 8k ground texture which is definitely not high enough). Again, would it better to split this into several smaller files?
  • What is the best way to increase detail gradually on the ground as I need it? For example, I might have large areas of the terrain which only need low mesh detail, but then suddenly there is a stream or a cliff which needs a lot of curvature as it drops down and curves through the landscape. Should I make the whole plane have many thousands of subdivisions so that at least I can add the detail I need but be cursed with a slow computer? Or should I add more detail where needed and have a very messy mesh?

Thanks very much in advance for your help. Any insight you could offer would be great!