Helicopter Recovery

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[pusser_uk]

Is there a trick to getting a helicopter to recover to the ship? I am talking in particular about the Campaign Mission "04 - No Scuttling". I notice that I have completed the mission successfully, but the helicopter did not recover to the ship, it just came to a hover close to and stayed there. I saw this also in another mission that uses a helicopter.

[pusser_uk]

I think its plainly obvious that nobody knows the answer to this. 

[kathy4691]

Landing the chopper on Esperanza’s deck at sea is very difficult to do gracefully. Perhaps that was not attempted. What was the chopper’s final position relative to Esperanza?
Campaign missions included with the game are locked, and cannot be examined in the editor. All one can do is play the mission. This rarely uncovers differences caused by one player deviating slightly from the way an experienced player, such as a CMM, would play the mission.
The best course is to contact the creator by PM and ask for help. He will have access to his original, unlocked, copy. In this case, the authors are Walter Swennenhuis and Maykel Boes of VSTEP.

[kathy4691]

We obtained an unlocked copy of the “No Scuttling” mission. Attached are shots of the last triggers in the logic for the choppers:
NS1 shows that the logic path was severed between triggers Land and End.
NS2 shows how the current version ends, with the chopper still airborne.
NS3 shows how the flight was originally to end, with the chopper on deck and attached to the ship.
The problem in landing the chopper on deck is that the target point is moving, either because the ship is underway, or from rolling and pitching. The chopper moves by interpolation to the target point. The coordinates of the target are saved at the beginning of the interpolation and may be somewhere else at the end.

[pusser_uk]

Thanks Kathy, I gather from the complexity of your reply, it is almost impossible to recover a helicopter and I just leave it hovering and forget about it. 

[kathy4691]

Because the desired landing point has moved relative to the saved target point, the result is seldom pretty. The chopper ends up in the water if the ship is moving fast, or half embedded in the deck if she is rolling or pitching.
It can be made to work if the ship is stopped and immobilized by an action; perhaps Entity—Disable Physics or Entity—Freeze. I’ll ask the Elves to play around with it to see what can be done.

[kathy4691]

From Gerard:
Neither the “Entity—Freeze”, nor “Entity—Disable physics “ actions will immobilize a ship.
You can achieve what I think was the intended effect of “freeze” by attaching (not mooring) the ship to a bollard. The bollard can be anywhere: Any existing bollard in the environment or you can drop an invisible bollard into the sea near the ship.
Attaching a child to a parent means simply specifying the origin of the child’s coordinate system in the coordinate system of the parent, effectively fixing the location of the child relative to the location of the parent. Bollards are attached to the coordinate system of the environment, so attaching a ship to a bollard fixes the ship’s position and attitude relative to the ground.
Attaching an entity also detaches it from whatever it was attached to before. In the case of a ship, this would be the dynamics (physics) that controls its position, velocity, and attitude in the sea. So, attaching a ship to a bollard shuts down its physics.
This should only be done at a dead stop in a calm sea; otherwise the visual effect can be ugly.
This only solves part of the problem of landing a chopper on deck: Unfortunately, when a chopper stops moving it often assumes a strange attitude such as nose up with the tail rotor embedded in the deck.
More on this later…

[Tonyevans@aol.com]

It is because of painstaking investgation of what might appear to be trivial, perhaps, that the simulation progresses. Hats off to Gerard, Kathy and her students for the attention given. Is the level of detail more suited to another Forum board where the topic might reach a larger audience? I only stumbled across it in General discussions.