DIY Unity Boat Movement

Ships are really cool. There are just soooo many types. Unity is also really cool. In my mind, I put those two things together, and I came up with an idea. I thought, What if I code a ship in Unity? So I did. This instructable will teach you how to design a ship that moves, floats, and looks good in Unity.

You will need the following:

1. A computer that can run heavy programs
2. An internet connection
3. Unity(https://unity.com/download)
4. Your imagination

Have all those things? All right then, let's go!

You are first going to want to make a new Unity Project. I would recommend using Unity 6.2 or higher. Make sure to select the Universal 3D core, then click the create button. When it is done loading, you can now start adding in the assets. For my ship, I found a free colonial ship on the Unity Asset Store(Colonial Ship by Nokobot), but you can use any ship you have. Once you have your ship imported(make sure to check the size and scale), you will have to add water. The Asset Store has multiple easy-to-use water shaders, but I chose URP Stylized Water Shader - Proto Series by Bitgem. Of course, if you have other water, you can use that as well. Finally, install Cinemachine 3 through Unity Package Manager. Go to the Window dropdown → Package Management → Package Manager → Unity Registry → Search Cinemachine → Install

Adding and rendering the Colonial Ship:

To locate the ship, go to the folder Nokobot → ColonialShip → 02_Prefabs. You will see two prefabs in the folder. One of them has decorations(barrels, boxes, etc.), and one of them is plain. Drag the boat of your choice into your prefabs folder, then drag it onto your scene. If your boat looks normal or bright blue, that is good. If it is bright pink, go to Window → Rendering → Render Pipeline Converter. Make sure to check all the boxes and then click Initialize and Convert. Once that is done, drag your boat into your scene. At first, the boat is very large, so you will have to scale it down. I would recommend a 0.1 scale.

Setting up and using the URP Stylized Water Shader - Proto Series:

If the video is blurry, watch it on YouTube or set the quality to 1080p

Adding additional water:

If you would like to create more than one water body, duplicate the WaterVolume element or the water's parent element. Make sure that when placing them, the overlap space is a bit bigger than the ship's body, or the ship will sink when crossing the border.

You will also have to add a tag to each WaterVolume. This can be any tag. Additionally, add a script to your ship. This will make sure that your boat can interact with all of the water. Once created, add the following to your script.

Due to Insturctables' code formatting, I put the code here: https://tinyurl.com/MultiWatercsharp

Play test your game. If your ship has a script called WateverVolumeFloater for each WaterVolume, then you are all set to keep multiplying your water and proceed. Make sure to tag the WaterVolume.

In Unity's new input system, you have to do some work ahead of time to ensure that your buttons trigger the script. Go to Edit → Project Settings → Input System. There you will find two pre-made input maps. Delete both of them and make a new map called Player. You will find a pre-made action in the already. Just rename that to "Forward". Also, locate the box labeled 'Action Type' and change it to 'Pass Through'. Click the plus button on the right side of the "Forward" row and then click Add Binding.

Then, in the binding dropdown, where it says 'path', type in your chosen key and continue. I used w and the up arrow for my up action. Proceed to repeat until you have Forward, Backward, Left, and Right. (The action names are case sensitive.) You can choose any keys for your move actions.

Once you have that complete, your input system should be set!

Obviously, you can't have an immobile ship. Add a script to the parent group of your boat. I called my script ShipMovement. Also, add a Ridigbody3D and PlayerInput component to your boat. Change your Rigidbody's mass to a higher number.

Additionally, locate the PlayerInput behavior dropdown and switch it from 'Send Messages' to 'Broadcast Messages'. Also, switch the default map to Player. This will ensure that your script receives your input function properly.

Here is the code with comments so you can edit it and follow along.

Find it here: https://tinyurl.com/unityboatcode

IMPORTANT: If you are using the OLD Unity Input System(Input.GetKeyDown), please find the code at https://tinyurl.com/OldUnityInput

If your boat is not responding to some/all input commands:

You might not have entered your input actions properly. The boat movement script listens for the actions, Forward, Backward, Left, and Right. Make sure that your input actions include one action with each name from the list. Also, make sure that you added bindings(Step 4).

If you get motion sick playing your game:

Click on your ship in the hierarchy. Then, in the inspector, go to the rigidbody component and find the constraints dropdown. Then check the freeze y position box, and your ship should now not move up and down

If you don't know what half of the variables do, then you've come to the right spot! Really learning about the code will help you fine-tune your ship's movement to make it look super realistic.

Depending on the type of boat you have, you will need different values for the physics variables. For example, if you have a jet ski, you might want to turn maxRudderAngle up. Or if you have a cargo ship, then turn maxThrustForce down and set throttleStep to something like 0.1.

To make sure your camera follows your ship, I'm using Cinemachine. Cinemachine makes sure that your camera moves smoothly and does not make your player get a headache. To attach Cinemachine to your Main Camera, right-click in your hierarchy, then find the Cinemachine option → Cinemachine Camera.

After that, set the 'Tracking Target' parameter in the Cinemachine Camera component to your ship's(or any other object the camera should follow) GameObject. To make sure that your camera always stays behind your boat, change the 'Binding Mode' dropdown to Lock To Target No Roll. This will ensure that your camera follows the boat smoothly. Additionally, feel free to change the camera offset to really customize how your player looks at the boat.

You now have a basic game with a boat that moves and floats. Customize it as much as you want. The possibilities are unlimited.