ACG - Creating a Virtual Record

The Airfield Construction Group (ACG), a small group of scenery design enthusiasts has been building detailed scenery for MSFS since it was founded in April 2009 after working together for some time before then. This article outlines the aims of the group, its achievements and current situation following the recent closure of the group.

Designing scenery for Microsoft Flight Simulator is a dilemma. There are two ways to go about it. You can custom build everything yourself, or you can use third party object libraries. The first method creates a lot of work for the designer, but is generally easier on the users because everything is self-contained. The second method is easier on the designer but generally creates more work for the users who have to find the libraries and download them separately. There’s no right way or wrong way – just a choice. ACG was firmly in the custom camp with a passion. I’ll try and explain why.


The first project began in a once very secret location with 3 layers of fencing, watch towers, machine gun nests and very thick structures.

Back in the 1980s, looking across the runway at RAF (USAF) Bentwaters in Suffolk, England, at the annual air show, you could just about make out the heavily defended structures of the weapons area in the tall trees. Never in my wildest imagination did I ever think that in 2008, I would be able to photograph the inside of one particular bunker in that complex. It was one of a number used to store nuclear weapons.


That was the start of the first project to be completed for FS9 and FSX by ACG. After a good many months of work, Ian McCartney and I had produced a super-detailed and accurate rendition of the base and its twin, 6 miles away, at RAF (USAF) Woodbridge at the time of closure in 1993.

The weapons area produced quite an atmospheric scene (the poles, just out of interest were to stop helicopters landing in the complex):



We worked with the Cold War Museum at Bentwaters to photograph every structure on the base. From those photographs we made photo-realistic textures for our scenery objects that were also accurate in size and shape thanks to the ruler tool in Google Earth. Although Bentwaters is still in a good state of repair today, Woodbridge less so, it was of great pleasure to us that we were able to recreate both bases as they were in the A-10/F-16 Aggressor era and to give them a new virtual life with added AI aircraft, both for the FS community and for the museum.



Preserving the architectural heritage virtually, not just of historic USAF airfields in the UK, but RAF ones too, was a prime driver of ACG designers who all shared that value. The group was named after The RAF Airfield Construction Branch that constructed and repaired runways, hard-standings, buildings and other facilities required in the United Kingdom and overseas until 1966 when the role was taken over by The Royal Engineers.

Stephen Legg (Stevo), who has a great interest in historic RAF building infrastructure was the group’s authority in every shape and dimension of standardised buildings that were often erected in the 1930s and are still in use today – the classic C-type hangars being a good example. Probably, the best example of ACG’s attempts to create a virtual record of historic RAF structures is the project he and I worked on at Duxford Airfield in Cambridgeshire, UK. Like the Cold War Museum already mentioned, we worked this time with the Imperial War Museum to create an accurate rendition of how the airfield looks today, including all the historic WWII buildings.



As a group, we were very keen to encourage others to design, particularly with Gmax. Manfred was part of the team from the outset. He is German and has a great interest in RAF Cold War bases that were active in his country during that era. His skills just grew and grew and working with Pete Beeby, who specialised in high definition ground polygons, they have produced some of the finest historic military scenery for FS9 there is. Gütersloh and the remote Harrier hides are prime examples of their work:




The detailed appearance and quality of the scenery is fine, but is pretty useless if it runs in the simulator as a slide show. With that in mind, ACG designers were as much committed to good performance as to visual appearance. It was the discovery of a very technical post by Microsoft that really gave us the methodology to produce very detailed scenery with high performance frame rates. It was entitled “Polygons don’t matter, Texture vertices do” and it gave us insight into how to achieve it. After much experimenting we verified what was being said. From then on we adopted the large Gmax scene approach, sharing one large texture sheet with welded common texture vertices on attached objects. The performance results in FS9 and FSX were quite phenomenal.


The last big scenery produced by the group was RAF Wattisham, circa 1991 at the end of the Phantom era. It was produced by Stevo and me with an opportunity to get to grips with high definition ground polygons produced with Gmax, thanks to some extensive tuition by Pete Beeby, who subsequently produced the optional seasonal textures for the FSX version:

Wattisham QRA



So why did the group cease? That’s quite a complex question. Primarily I think it’s because it takes an enormous amount of time to produce these offerings – typically 1-3 years and 2000-4000 man-hours each time. Because progress was often slow and the number of projects small, it became difficult to maintain interest on the team’s web site with updates of progress. Users probably didn’t understand just how much work goes into projects like these and there was sometimes a feeling of uploading into a “black hole” when few people actually said anything at the end of them. The dilution of the “market” into the 3 versions of MSFS – FS9, FSX and P3D probably also played a part.

For me personally, the Duxford project was a turning point in my long standing interest in scenery design. I chose to model something that had always been afraid to tackle: a 3-D aeroplane. I enjoyed the learning from the modelling immensely, but the eventful moment came when I included an .air file and aircraft.cfg, made a short circuit flight plan and let the aircraft loose. I was so amazed when it took off and even more so when it returned to land. I was hooked on AI from then on and I went on to produce 20 different historic AI aircraft for the Duxford packages in both FS9 and FSX native code. There was never a great interest in AI from users at ACG and I found myself more and more a part of MAIW, particularly as people here taught me new skills. That I know diluted the scenery resources at ACG, but without a second string to my bow, I may have given up altogether.

Although the group produced historic airfields, it also produced custom modern ones too – Marham, Congingsby, Cranwell and Lakenheath for example. These had been produced or were well advanced before the current global threats and it left us with the dilemma as to whether continuing such work was sensible. That prompted much debate after a decision by Ian to discontinue his Lakenheath scenery.

The final ingredient in the closure decision was a failure of the outdated web site software. The amount of work required to re-build it on a more modern platform was not considered worthwhile in view of the very low traffic levels we were experiencing.


I’m pleased to say that we have a way forward. Thanks to a kind offer by MAIW to host the ACG files we can continue to preserve the virtual heritage here as well as at Avsim. It has also given ACG designers a new forum to show their work at their own pace without having to worry about generating web site traffic. You can see a great example of that in recent days at MAIW, with Ian’s decision to re-instate his Lakenheath project, albeit with more sensitive areas like the gates and domestic areas removed from the scenery.


MAIW and ACG have worked together in the past with ACG scenery supplied to MAIW packages one way and MAIW aircraft to ACG the other and a new home for our work here continues that relationship.

With that in mind, I’ll upload more of the past ACG offerings for users here that might have missed them previously. We hope you will enjoy them as much as we have in making them.

John Young