Terrain in Blender - Option 2: Mirage
In my first post about creating terrain in Blender, I discussed using BlenderGIS to combine multiple georeferenced sources into a single terrain. This post will deal with the addon, Mirage, which I feel is better suited to creating either imaginary terrain, or terrain from an existing heightmap and then adding procedural rocks, trees, vegetation, snow, etc. as material(s) on that mesh.
Disclaimer: This is an initial look at Mirage, and specifically looking for ways to get real-world elevation and topography into blender environments. Mirage is capable of much more than I am discussing. Hopefully, I will do a more in-depth review in a later post.
Before getting to Mirage, let me put in a plug for QGIS. There are times that I want to either use a portion of an image (usually for elevation data), or merge multiple geo-referenced images togehter (usually for a high-resolution image overlay). The Geo-spatial Data Abstraction Library (gdal) is an open-source library that handles geospatial data. Most of the tools I found used gdal under the hood. But I struggled to find a tool that didn't have a steep learning curve. QGIS is that tool, for me.
To get started with Mirage, you will find a 'Mirage' tab in the N-panel of the 3D viewport. I had the best results when I converted Digital Terrain Elevation Data (DTED) into a image file (QGIS to the rescue!). By using the 'Detail Level', I can set the number of desired vertices, allowing me to use rough approximations early and increasing fidelity later when I needed it. Unfortunately, that requires creating a new mesh; you can't update the 'Detail Level' after terrain has been generated
With the new terrain selected, the Mirage panel provides tools for selecting vertex groups based on face slope, face relative elevation and others. These vertex groups allow materials to be distributed based on elevation or slope. For example, the image to the right uses materials based on a color ramp. The input to the color ramp are these vertex groups. Instead of color ramps, various types of vegetation materials could be used (grasses in the valleys, trees on the lower slopes, bare rocks on the peaks, etc.).
Mirage obviously has much more to offer. My initial interest was how to turn elevation data into a mesh in support of activities like architectural visualization. That process is much easier than it was even a few years ago. It still requires some effort. These two addons, BlenderGIS and Mirage, make the process easier, quicker and less error-prone!