Since the terrain in Lacuna Passage is essentially its own character in the game I decided to drop the composite Photoshop method and look into generating higher fidelity terrain directly from the Mars HiRISE digital terrain IMG files.
As it turns out, there is an add-on for Blender that allows you to import the large IMG files to generate a mesh. Huzzah! Exactly what we need. There are others who have already documented precisely how to utilize this add-on so rather than reiterate their instructions I will simply link to a tutorial video that explains the process very well.
While Blender is great (and free) I preferred to export the final mesh to 3ds max to create our heightmaps. Once in 3ds max you will likely need to flip your normals so that we can unwrap the mesh correctly and generate a heightmap.
As we already know, a heightmap consists of a black to white gradient to convey height, so we need to devise a material for this mesh that will render that gradient. The easiest way to do this is to apply an unwrap modifier to your mesh and planar map the entire thing from either side (doesn’t matter which side, just NOT a top down plane). Then we can apply a black to white gradient material with 100% self-illumination. These steps are probably easier to follow in video tutorial format, so once again I will link you to someone who has already explained the process quite well.
Once you have your gradient material applied to your mesh you can effectively render out whatever sized heightmap you want. Obviously you will have diminishing returns at a certain point where the resolution of the mesh itself limits the resolution of the heightmaps you can render, but these are still much higher quality than the jpeg images provided via HiRISE.
Now you might be asking, “But how do I ‘customize’ my terrain? It seems like I’m limited to only the geometric features provided in a single HiRISE IMG file.” This is true; however, this is where we can implement a new method for compositing. If you have access to Mudbox you can create sculpting stamps from individual components of your rendered heightmaps. For a third and final time in this devlog I will defer to other skilled artists and link you to an example of how this could be used to create some of the most realistic custom terrains you will find anywhere.
During the development of Lacuna Passage we will be using a combination of nearly all the methods described in this post and the post from last week. The game will have an expansive open-world terrain and the goal is to make every inch of it worthy of exploration. Make sure to follow us on twitter and facebook for more updates.