First tests and thoughts with Aerofly FS 2 scenery creation
Aerofly FS 2 is one of those simulators that people seem to leave out when discussing flight simulation. Usually they claim it lacks many features that its other bigger and older cousins have, e.g. (Water, seasons, road traffic, ATC and also any in depth systems). I personally became interested in AF2 after trying it in VR and found it was the only flight sim that gave me smooth performance on high settings (Followed by native VR in P3D, and then X-Plane 11).
Aerofly has a simple scenery system that is completely ortho (aerial-imagery) based. There are no landclass tiles, water, roads, or a way to place your own textures onto a mesh. The base sim ships with scenery for a large area of the US west coast and there are free and paid addons to add more US states or Switzerland (From v1 of the simulator). The regions they have are very well done, with good populated airports, cities and areas of autogen. My favourite was New York city which was incredibly smooth, and also the area around San Francisco. There are also some high quality payware airports available from ORBX and I’m sure more will follow.
It was only natural for me to get my hands dirty and to start working on tools to generate sceneries for the sim. There is an SDK that allows the creation of ortho tiles and also cultivation (which is Aerofly’s name for autogen). The tools however are difficult to use, especially if you want to generate a large area, since it either requires the manual downloading of GeoTIFFs, or preparing your own files for each image downloaded along with a mask. I studied the grid system in AF2 and created a utility to download tiles automatically from a WMS source (Or something like Bing, Arc, etc), generate a mask and add geotagging information. The utility then creates the relevant files and config for each tile (Basically adding geotagging information) and calls the SDK tool for you to generate a tile. If anyone has used Ortho4XP on X-Plane, it works in a similar way.
I then had a look at the cultivation system, which is pretty basic. It allows rectangular buildings, individual trees and lights to be placed. The system reminds me somewhat of the autogen in ESP sims (FSX, P3D etc), however it is still quite limited:
- Each building has to be rectangular. Creating larger buildings with more complex geometry is difficult (See later)
- The buildings can only be of two types: residential, and industrial. There is no way to decide which texture you want, it gives one at random
- You can specify a building height per rectangle
- You have to attach your autogen to an airport which has a runway. The airport will have a limited range set, and once you go outside of the range, your autogen won’t show. (This was incredibly frustrating to work out. You need to create a fake airport with a runway sunk into the ground for your autogen to show up). For large scale areas, several fake airports would need to be created.
- The roof type can be gabled or flat. I quite like the gabled roof feature as it’s something the facade system in X-Plane lacks, although to be fair, the AF2 geometry is much simpler.
- Only individual trees can be placed.
Autogen is placed into a text file with the extension .TOC, along with the fake airport files, and a folder containing basic building textures. The files are then processed by the SDK tools and the output files (with the same extensions) are placed into your scenery folder. I added basic support for producing these TOC files and fake airports to W2XP, which will also run the conversion tool, automating most of it. I gave the tool some data for the UK (but this could just as easily have been OpenStreetMap data), and it generated a large area centred around EGGP Liverpool Airport.
The first tests with the generated scenery were quite pleasing. It looked much better when using VR than in 2d, and performance was incredibly smooth (easily reaching 100fps or so). In order to get the scenery looking more natural, I firstly needed to fill forests with individual trees. A tree can either be broad or conifer, so it was easy enough to create forests based on the data, e.g. Mixed, Broad, etc… However, there didn’t seem to be any way to provide your own tree textures.
The second challenge I faced was the limit of rectangular buildings. To get round this, I added some code to attempt to break up complex non-rectangular buildings into smaller ones, some of the results can be seen here:
This results worked surprisingly well, as shown below:
One issue I found is that since Aerofly will randomise the building textures per rectangle, any split geometry can look a little messy if different roof textures are used. I couldn’t find a way to control this, but hopefully there will be support and more control in future versions. Even with the splitter working, performance was second-to-none, with not a stutter in sight and quite the experience with a VR headset.
The area I generated with orthos and autogen was approximately 100km2. The slowest part was the geoconvert tool that converts the downloaded tiles into an internal gridded compressed file format. For an area this size on my machine it took around 6 hours, but luckily it could be stopped and resumed later on. Additionally, the geoconvert tool can create several versions of the orthos at different zoom levels. I used level 14, which is approximately the same as Ortho4XP’s zl16 on X-Plane (Approx 2m per pixel at 50°N).
In summary, I was pretty happy with my initial efforts and experimentation. For a young sim (compared to X-Plane and ESP), it has some exciting tech that is only going to get better and I’ll be watching as these develop. What I’d like to see added in the near future are:
- The ability to have standalone cultivation sceneries not attached to an airport
- The ability to choose the textures for each building as well as at random.
- The ability to customise the tree textures
- The ability to create or convert 3D models using open file formats such as Wavefront .OBJ files.
The last point above is important for any tool that needs to create large scale scenery. Without the ability to generate 3D objects on the fly as I can in X-Plane, it’s going to be hard to create realistic city or industrial buildings automatically. Additionally, I would like to be able to create my own 3D models such as wind turbines etc using Blender rather than the expensive 3DS Max or AC3D. A command-line converter from open formats would really help here and I believe that once iPacs add support for Blender or Sketchup, the freeware community will grow along with the simulator.
I’m now curious to try some more regions out and the next place I’ll try is going to be New Zealand which should really shine in this sim.