This is a very basic instructional - not a tutorial, on how to add things to a ship. I will assume that you have a basic understanding on where to place files, make changes to data inis and if you don't know where your mod folder is located - move on because this is over your head. This will not be the place to explain any of that and you're better off reading up before you tackle this mod.
Now, you will need a few things -
a ship - in this case a carrier but any ship or sampan will work if you mod it correctly.
a plug - in this case its a plane that can't take off. The plug should be as simple as possible. By this I mean paper airplane with wheels and very ultra low poly. You don't need to make it pretty because you won't see it at all. You must have the 3d model for this plug.
a data ini for the ship - latest one is always best.
an object to place on the deck - a crew, a plane or whatever you want.
an image editor - Photoshop or whatever
a 3D modeling program - Max if you got it or anything else and a friend who has Max and the latest exporter.
ability to UV map
Lets prepare our ship first. What I do first is start a mission with the ship, clear skys and noon settings. Launch the plane and wait for the cats to retract. What you ant to do is take a screenshot of the deck from straight above. I hit pause and Ctl+F12 or Shift+F12 - I forget which one gets me in roaming camera mode. Anyway, line you shot up so that you get the deck to fill up the screen without cropping the edges of it. Take the shot and save it - use BMP for this because JPGs look ugly...you want a clean crisp shot without any major distortion. Create a folder with the back up copy of your ships data ini, the screenshot of the deck and the plug model. Take that image and open it up in Photoshop or whatever image editor you use. What you want to do is make it a bit sharper and crop all the unneeded ocean out.
Look at this image of the KittyHawk as an example of what you want...I reduced the size for forum purposes BTW.
Now open Max up and create a rectangle that has the same dimensions as your cropped deck image. Make sure that rectangle is set to XYZ 0,0,0 and facing Z or UP for those who don't understand modeling lingo. Now would be a good time to UVmap that rectangle to the deck image. While Max is open, go ahead and import/merge your plug model and whatever object you want to SEE on the deck. Ensure you link the deck object to the plug model so that the hierarchy is linked to the fuselage. What I do is make a simple box and name it LINKER and link all my deck objects to it - things get messy when you have a full deck of planes, crew, vehicles and clutter. Place that linker at XYZ 0,0,0. Now link the linker to your plug and you can keep things nice and neat in Max. Ok, go ahead and place the objects wherever you'd like but stay within the bounds of the deck image below you...don't need to have objects blocking #3 and #4 catapults.Save the model and close up Max.
Open up the ships data ini and add another catapult. How you ask? Like this -
Add this line to the HULL section
[Hull]
ModelNodeName=Hull
EffectSize=1.0
MaxExtentPosition= 28.98, 181.63,19.58
MinExtentPosition=-28.98,-120.50,-3.98
StructuralFactor=10000.0
HasArmor=TRUE
ArmorMaterial=STEEL
Armor[FRONT].Thickness=100
Armor
.Thickness=100
Armor
.Thickness=100
Armor[REAR].Thickness=100
Armor[TOP].Thickness=100
Armor[bOTTOM].Thickness=100
SystemName[001]=Engine
SystemName[002]=Deck
SystemName[003]=Cat1
SystemName[004]=Cat2
SystemName[005]=Cat3
SystemName[006]=Cat4
SystemName[007]=Cable1
SystemName[008]=Cable2
SystemName[009]=Cable3
SystemName[010]=Cable4
SystemName[011]=Plug01 <========== add the entry here...notice that 011 comes after 010?
...and after the last catapult section add your plug data block
[Plug01]
SystemType=CATAPULT
CatapultID=5 <---------this number should be the next one in line. If you have 4 cats, make this 5. If you have 2 make it a 3 etc
StartPosition=0,0,123456789 <------XYZ of where you want to place the catapult to start.
EndPosition=0.0,0.10.0,123456789 <-----XYZ of where you want the end of the catapult to be.
LaunchTime=999.0 <------VERY important number - this tells the game how long to wait for the launch - make it 999.0
LaunchEffect=
CatapultEffect=
ReadyAnimationID=5 <---should be same number as catapult ID number
ReadyAnimationTime=999.0 <------VERY important number - this tells the game how long to wait for the launch - make it 999.0
Whats with that 999.0????? That was the missing key to using fake catapults. They would always launch and form up on your wing. BTW, make sure you drop a copy of your edited and BACKED UP data ini into your mods ground objects folder. While you're at it, make a folder with you plug name and drop a copy of everything you will need to make it "fly" - that means all ini , you texture folder and the LOD.
Ok, you have the basic plan set and now all you need is to do is make sure your objects are where they should be. This is where things get tricky and a knowledge of decal placement comes in handy. Firstly, know that this is tough but not impossible. If you have the ship model, this makes things much easier.
Start a mission that has the same amount of cats + one more. If you have 4 the make it 5. In the loadout section your first 4 planes are whatever you want but the fifth MUST be your plug. I name mine something obvious like F4plug. Make sure that your plug is the last one in the mission because its basically going to be married to that cat forever. Launch the mission and hit F7 so you can find the linker model. Its not always where you think it is. Now, if you're lucky it will be ON the deck without sinking or floating. If its close just adjust the height of the plugs catapult until it sits right on it. If its floating way up there or sunk way down there, check your Z coordinates in Max - it should be set to 0,0,0 Once the deck elevation is set. Don't mess with it. I usually move the deck rectangle in Max until the objects are just resting upon it. Now comes the part where you move deck objects around the X and Y coordinates. If your deck rectangle is off, move it around the X and Y until it closely matches. Takes some time but in the end it pays off. Once all the axis are set, feel free to move the deck objects around by using the deck rectangle with the image as your guide.
BTW, you are not limited to just objects. Remember that this is a fake plane, a fake catapult and plane can take any shape - like an entire squadron of A-4s ready for some action. What else do planes have? Lights, props and sounds. All these things can be added with a bit of imagination and thinking...err...hacking outside the box.
Ask questions here so that I know if I left anything out or just need more clarification. Do you have a better way to do something or explain it better? Please do it here so that all the info gets compiled in one spot and people don't go looking all over for it.