The Industrial Terrain from GrimDark Terrain is compatible with 6-8 mm Epic Sci-Fi games. It fits perfectly into your terrain. Whether Warhammer 40K or other sci-fi tabletop games, it simply fits many settings.The Ares Vulcano Defense Cannon consists of 11 parts and measures approximately 102x100x77mm. You can find assembly instructions here:
https://grimdarkterrain.com/template-construct/ares-vulcano-cannon/
We have many other terrain models and also Greebles/Bitz on offer. Just take a look around.