03/01/2021 – This project has probably been somewhat enigmatic, so for this post I wanted to break down the inspirations as well as write on the design of the ship, both from a practical perspective and from a story perspective.
The biggest visual inspirations are the VF-2SS from Macross II, the eponymous Silpheed, and lightfighters from Tron Legacy, all displayed below in that order.
For the missiles, I was heavily inspired by the recognizable near future look of the weapons from the anime Yukikaze, as seen below:
The ship is of course also meant to be a part of the Freespace universe so it has some elements that are inspired by the GTF Perseus and to a lesser extent the GTF Myrmidon, shown below:
So with that barrage of primary references out of the way, time to elaborate. The VF-2SS is part of a long line of transforming fighters within the Macross franchise, all strongly inspired ultimately by the real life USAF F-14, in particular the 103rd Strike Fighter Squadron. The technological marvel of the F-14’s swing wings captured the imagination of the people who went on to make Macross – compare the F-14 with the VF-1 from the foundational Macross series below:
The VF-2SS is a perennial design touchstone for me as it’s still got strong visual similarities to real life jets like the F-14 but has a more fantastic and ornamental quality to it. Whenever I sit down to design something that evokes elegance and speed, I often find myself cribbing the distinctive dark ridged panel directly behind the cockpit canopy of the VF-2SS, as well as the curved fuselage and the V-shaped main body. It’s entirely fair to say that first and foremost the Achilles is a love letter to this specific design. Ever since my infatuation with Homeworld I’ve preferred science fictional designs that are visually enjoyable from the front, top, and side. The VF-2SS possesses one of the most dynamic side profiles of all the fantasy transforming space fighters from Macross. Like all good creative endeavors, Achilles began life inauspiciously as a product of frustration with what already existed. Freespace is interesting in that it typically features extremely chunky ships, most unsatisfying of which is the GTF Hercules Mark II.
The Hercules II is interesting because it has a very recognizable streamlined fuselage and canopy – it wouldn’t look out of place if you cut that fuselage out and put it on a Macross ship! However it’s body is a lumpy blob with circles on it to suggest missile and gun ports. In terms of gameplay, the Hercules II was sluggish and unresponsive – hardly fitting for its namesake! So the Achilles began life many years ago as a few lines of text in a configuration file for a mod in Freespace Open – without any planned design or shape, it was going to be an iteration on the Hercules. One of my pet peeves I’ve talked about with Freespace is that its missiles have fantastically diverse shapes but all come out of these nondescript ports just like the ones on the Hercules II. So my Achilles design needed wings, if nothing else to serve as mounting points for missiles. Macross came to mind immediately, thinking about that jet like fuselage on the Hercules II, and from there the ship’s basic plan began to take shape.
This leads nicely to the Silpheed. This design is sleek and aggressive when viewed from the front, but with a dynamic shape when viewed from the side – it’s not nearly as flat or planar as you might be lead to believe by the front view.
Just like the VF-2SS, it is clearly evocative of modern jet planes. It has two roughly triangular wing like shapes extending to the side, with a roughly triangular general hull plan. However it’s body is split into a Y shape when viewed from above, and the chunky components have a deliberate lack of streamlining to imply that it’s meant for a space environment. It’s a design full of symbols to explain that it’s futuristic but not so far that it is totally unrecognizable. You might not be able to imagine it plunging into re-entry like the Space Shuttle does, but its white coloring and stubby winglets also evoke that real life vessel as well.
For the Achilles I wanted to tap the Silpheed to channel some of the functional chunkiness of Freespace designs while also bringing in the kind of flashiness that best comes from anime and japanese videogames. The gigantic super cannon’s placement underneath the main body is pure Silpheed, as opposed to over the shoulder like Macross tends to. The in universe predecessor to the Achilles, the Hercules, is a heavy fighter so the split-Y body plan of the Silpheed was also a way to stretch and enlarge the design. It also was a way to add a lot of functional details. 
This is cropped from the side view of a previous p3d I’ve posted. I’ve tweaked the linked p3d model to actually load into this exact view. Here we see the side of the split Silpheed style tail of the Achilles, where I’ve placed a number of glowing 0-shaped lateral thrusters. Without any atmosphere to drag against, turning in space requires thrusting. This is meant to allow both turning and lateral sliding while maintaining the same direction of thrust. Those same limbs also mount forward-facing thrusters:
This is because in a vacuum the only way to slow down is by thrusting in your direction of travel. Having engines facing to the front allows a spaceship to slow down without turning around and firing its main, rear-directed thrusters. They can also be used to rotate the ship, by only firing one set. You can also see that the same model of engine in these braking thrusters is used in the main engine modules, seen below.
These backpack structures house the four clusters of engines that provide forward thrust for the ship. The Achilles has between a third to one half strength on its forward thrusters, compared to the big rear thrusters. As the fanproject it was a part of developed, the Achilles acquired more of an identity and more distinctive gameplay: a heavy interceptor, akin to the Cold War era MiG-31 – capable of extreme linear speeds and acceleration to quickly respond to bombers at long range. This is also why the three large fuel tank structures were added in protected locations, slung under the belly and in the backs of the Y-shaped legs of the ship – an attempt, in addition to the abundance of visible engines, to communicate the ship’s role as a long-range, high speed interceptor.
All these screenshots of the actual Achilles model leads nicely to the question: what is Tron doing in the list of inspirations and references here? None of the linked Freespace ships have anything beyond a few small bars of glow on them, so doesn’t the Achilles represent a huge departure from the visual language of the universe? There’s two answers to that. One, Tron looks simply awesome – and the way that it looks awesome is very useful. Everything’s outline is clearly highlighted and easy to track especially against a black background like space. Direction and motion is clearly communicated as well – once you know that unlike most modern jet aircraft everything in Tron is forward swept, you know where everyone is going even without the trails. The second answer is in the enigmatic antagonists of the Freespace universe, the Shivans. I’ve done a fighter of theirs before that I called the Sharabha, The Shivans do use this Tron coloration, and they use it for the exact reasons that I listed above: It makes them identifiable and distinctive for the player of a Freespace game against the dark background of space. They have an eerie, stained-glass pattened glowing red texture across most of their ships:
Within the universe of Freespace, the Shivans are presented as an uncommunicative and eldritch threat. The Shivans make their introduction to the story as humanity is having WWI style dogfights with their local competitor alien species, the Vasudans. Space fighters on both sides look like militarized rocket ships, and the weaponry seems (and feels) primitive – slow firing bolts of light and unguided rockets. Next to that, the first Shivan incursion’s vanguard are fighters with invisible energy fields that render them all but immune to the weapons of either combatant in the Human-Vasudan war, and also render them invisible to the radar technologies of the era.
This is the point where the original Freespace game hooked me, as it was one of gaming’s great moments of raising the stakes. The player’s first encounter with the Shivans is not that hard to survive and you can actually triumph against this foe without too much trouble, but the story sells well the idea that the Shivans come from a far more advanced technological base. They earn their nickname after the capital ship leading their invasion force punches through the entire Vasudan military without any weapon the now desperately co-operating humans and Vasudans have slowing it down. From the Bhagavad-Gita, quoted by Robert Oppenheimer, these antagonists get their name (and by association, a semi-divine quality) “Shivans” after they become destroyers of worlds.
The second game in the franchise opens with a cinematic reinforcing the tone of the whole universe as morbid and stark. Freespace’s antagonists are unknown, uncommunicative, possibly uncaring. They’re straight out of a cosmic horror story – except one of the other things that happens in these games is that (largely) through the heroic action of the player, a number of Shivan ships are captured and some of their technology is reverse engineered and deciphered. So with the Achilles being a product of another generation of technology beyond the first Shivan war, now human ships are starting to more fully resemble those of the Shivans as more and more of their technologies, and presumably their actual components, are used in these ships. Tron-like aesthetics have always been one part of the Freespace universe, just confined to the eldritch antagonists. This Achilles fighter is in part an attempt to depict the evolution towards a more level technological playing field.