Hi everyone!

Following up on last week's 6DOF physics update, I wanted to share our current progress on **relative docking**! I've attached a video showcasing a fighter landing on a moving carrier in real-time (work-in-progress, but the core frame-of-reference math is now working). It's progress but still need some smoothing when entering and leaving in high speeds is needed.

Alongside docking, I’ve been refining our Large World Coordinates (LWC) spatial system in UE5 for double-precision stability, as well as squeezing out extra performance with data compression.

Here is a breakdown of the technical issues we tackled this week and how we fixed them:

# Technical Breakdown & Bug Fixes

# 1. Jittery/Stuttery Rotation When Docking on a Moving Carrier

* **The Issue:** Rotational smoothing was completely bypassed whenever a ship entered a relative movement zone, causing every micro-rotation of the carrier to hit the player ship as a harsh frame-by-frame stutter. To make matters worse, the camera's aim director was running post-physics and applying parent rotation deltas every frame, causing a phase shift and desync between the netcode prediction ticks, camera, visual mesh, and physics state.
* **The Fix:** Re-enabled rotational smoothing for relative movement zones by smoothly interpolating rotation offsets toward identity. Synchronized aim-director updates directly with network state ticks so parent rotation deltas apply on the exact same frame as movement.

# 2. Violently Oscillating / "Sticky" Landing Gear

* **The Issue:** The landing gear damping force along the spring axis was calculated using raw spring-axis velocity multiplied by friction and mass—missing delta-time scaling and impulse caps. This created a positive feedback loop: pressing into the ground generated an unscaled force that catapulted the ship upward, causing violent frame-by-frame flipping.
* **The Fix:** Scaled damping forces by delta time and clamped the maximum impulse to prevent it from exceeding the force required to stop axial movement. Separated the magnetic ground-attraction force (now a constant/clamped downward pull) from damping friction.

# 3. Rolling 90° Causes Unwanted Sideways Drift

* **The Issue:** The aerodynamic lift vector calculation contained a matrix transformation flaw that simplified to applying lift straight up against world gravity, regardless of ship orientation. Rolling 90° put the wings vertical, but lift kept pushing world-up, producing lateral drift. Additionally, the automatic bank-to-target mechanism during mouse aim fought manual yaw and strafe inputs.
* **The Fix:** Fixed the lift vector calculation so force always aligns with the ship’s local Up axis, properly scaled by Angle of Attack (AoA) and forward airspeed.

# 4. Loss of Inherited Speed When Exiting Moving Carriers

* **The Issue:** Zone-transition logic calculated inherited world velocity correctly (combining ship speed + carrier speed, e.g., up to 57,000 cm/s). However, in the exact same frame, velocity was clamped against the ship's standalone maximum engine speed (e.g., 2,000 cm/s), causing the ship to instantly lose over 90% of its momentum upon exit.
* **The Fix:** Removed the hard top-speed clamp during world-zone handshakes. Re-routed max speed limits to only restrict active engine thruster acceleration, preserving high-speed velocity inheritance when exiting moving structures.

# What's Next?

This Monday, we are recording a full multiplayer gameplay demo showcasing fighter-to-fighter and capital ship combat. We’ll be highlighting our dynamic destruction system (built using Geometry Scripting), where broken hull pieces retain physics and can physically damage ships or plunge into planetary atmospheres.

For those interested in the universe background, here is a quick snippet from our lore logs:

>**\[SOL Station - Personal Log // Year 7337\]** *"Twenty years... It’s been twenty years since that solar flare hit Earth. The few of us who managed to escape fled in whatever improvised generation ships could fly. We gathered in tight orbit around the Sun to build SOL Station—a fragile sanctuary running on pure solar energy. Today, the station relies entirely on us pilots, risking our necks in the cold outer solar system just to haul back basic water and food..."*

Happy to answer any technical questions about relative frames of reference, netcode prediction, or UE5 physics in the comments!

Sirius Relative Docking in Action + Physics & Flight Model Fixes (UE5 / LWC)