Before you start
Prefab Size Limits
The maximum height a prefab can be is around 250-256 blocks/metres high. While there is no hard limit as far as I know on width and length, there is an issue that occurs with large prefabs 250-300+ with the distant mesh overlaying itself over the prefab while you’re inside it. While it’s possible to overcome this issue, we’ll just keep things simple. Size obviously depends on what your building but the smaller it is the easier it will be. Try to aim for no larger than 100×100 if you want it to be compatible with the vanilla RWG generator. If you plan to place it manually, 200 should be ok.
Currently there is a ceiling of around 250-256 sleeper volumes before is starts acting buggy, but if you follow the size recommendations above you shouldn’t need to worry about it. Lights also have 2 limiting factors. 1 performance, lights are very taxing and lots of bright lights with a large range can quickly turn things into a slideshow. The 2nd factor is you can only have custom settings on a limited number of lights. I don’t know the exact number but i’d guess it’s somewhere between 100-256.
Create a new prefab
Once your in the prefab editor, first thing to do is press ESC and go to the last tab (Prefab Browser) Then “create new prefab”. You’ll be asked to name your prefab, so any name will do and it can be changed later. When renaming a prefab you can just rename the files of the prefab found in C:\Program Files (x86)\Steam\steamapps\common\7 Days To Die\Data\Prefabs
There will be a handful of different files for each prefab, just watch out for the .NIM file. It has a double extension and it’s easy to overlook. So don’t forget the .blocks or it won’t load.
Now that it’s been saved you can press ESC and click on save at any point. I’d highly recommend that you create backups and keep the last several. So if something goes wrong or you make a design mistake, you have previous versions to revert back to.
The prefab editors bread & butter is the selection tool. You press Z and a blue box appears, press it again on another location and the box will fill the area between the 2 points. Using the selection boxes you can create walls in a couple seconds, limit other tools to a specific area, copy and paste entire sections (or even whole prefabs). You can change it’s size by holding SHIFT + G then drag the 3 arrows in the direction you wish to expand the box in. You can also move it by holding G then using WASD and SPACE for up and C for down.
You’re already in debug mode when you load into the prefab editor. So to open the creative menu just hit U. Here you can get all of the blocks you need. I’d recommend you use the mutiblock variant type blocks if you can, just to save you having multiple concrete blocks on you for example.
If your prefab is intended to be player exploreable, you can add Sleepers too it with the editor. Adding sleepers is a 2 part process, first you need sleeper blocks. These control individual zombies/sleepers. Then you need to group your sleepers in Volumes to control group behaviour and when they spawn.
You can find the sleeper blocks in the Creative menu. There are 2 main types of sleeper blocks, the 1st is generic zombies and the 2nd is individual animal sleeper blocks. Although the zombie blocks all look the same the actual type of sleeper that zombie becomes is controlled by the Sleeper Volume. The blocks control where in your prefab zombie sleepers spawn and what “sleeping” position they will be in once spawned. They also control individual zombie sleeper behaviours like hearing and sight range, so you can set up monster closets. The animal sleeper blocks are a little different as these will determine what animal the sleeper becomes regardless of the volumes settings.
Once your sleeper blocks are placed you can start grouping them into Sleeper Volumes. If you go to the Level tools tab in the editors tab menu you will find a checkbox called “show Sleeper Volumes”. Once this is enabled you can start editing your volumes, you might not have any volumes in a new prefab and if that’s the case just load up another prefab that does and check the show volumes if it isn’t checked already.
Then you can simply left click on a volume and copy it CTRL + C then go back to your prefab and paste it anywhere CTRL + V. Alternatively there is a “cpy Sleeper Volume” button in the Level Tools tab that can do the same thing. Once you have a volume in your prefab you can just copy it to get more.
To change the volumes settings, left click on a volume and the edges will turn green. You can move the selected volume the same way as the selection box discussed earlier. If you press K you will get the sleeper volumes settings. Here you can select the group of the type of zombie you want to spawn, so if you wanted soldiers select “Group Zom Soldier”. You also need to specify how many zombies will spawn, i’d recommend you only spawn as many sleepers as you have sleeper blocks placed. The 2 boxes for “spawn Count” are minimum and maximum. If you want a set number to spawn everytime just set the same value in each box. If you want them to spawn in the same place everytime enter the value of the total sleepers in the volume in spawn count boxes.
Giving Your Prefab A Distant Mesh
I’d recommend you do this part last. For the most part it’s a one click deal, however it might need some tweaking before hand. Before you click on “update Imposter” to create your mesh i’d recommend you make a backup first and make some edits before going ahead. You want the mesh to be essentially an empty shell, so block up any holes that are open into your prefab (Any Marble painted blocks work well). Another thing of note is terrain won’t “convert” and will simply disappear in the mesh. So if your prefab has raised terrain on the exterior, you will need to use conventional blocks and paints to approximate the terrain for the mesh.
Once your prefab is prepped and ready hit “update Imposter”. This will create a basic version of your prefab and if you sealed it up right, it will be hollow inside. Do NOT save while “show Imposter” is checked it will save the imposter over your actual prefab. Make sure the main prefab is loaded before saving. You can then rename the new .Mesh file if you made a new prefab version for the mesh creation.