After creating several solar systems from scratch, I realized that I could help other players by providing a guide. Here we are!
 
Consider rating this guide and leaving feedback if you like it! If you want to make my day brighter, check out my Workshop uploads:D
 
 

1. Choose the planets that you would like to use

-Determine which planets you would like to use. This step is not necessary if you only want to use vanilla planets. If you wish to use planets from mods then subscribe to them and remember their names.
 
 
 

2. Create a new game by using the “Empty World” preset

-From the main menu click “New Game”, then click on the “Custom Game” tab. Select “Empty World” from the list of Custom Game presets. This preset gives you pure, empty space that allows you to place your planets anywhere you like. Do not start the game yet. There are many things to do.
 
 
Now is the time to decide whether this star system should be used for Survival or Creative. Select Survival if you want players to use your star systems for survival games. Select Creative if you want players to use your star system for creative games. This is not necessary. Players can change the game mode at any time once they start. It is useful to set the star system to the desired game mode before uploading.
 
 
 

2. Setting up Advanced Settings

To access advanced settings, click the “Advanced” button. This guide will not cover many settings, as you can modify them after creating the world. We will discuss some settings that you can’t change after creating the world.
 
 
-Asteroid amount is the first setting you should look at. This setting will determine how many asteroids you will have in your world. Higher settings will result in more asteroids packed together, while lower settings will result in fewer asteroids spread out over a larger area. Personally, I prefer the “Lowest Density” setting because I like lots of open space and other settings feel too crowded.
 
 
-Enable unknown signals is another setting that should be changed. This setting should be disabled. Unknown signals that spawn while you are creating the star system can be distracting and will also leave grids in the world for upload to the Workshop. This setting can be modified after the world has been created so it’s not a big deal to disable it.
 
 
The next settings to explore are those that involve NPC spawns. NPC spawns only consider the planets in the world at the time it is loaded. If you start the world with NPC settings activated, they will not spawn since there are no planets at the time the world was created. This “check” will not take place if you disable NPC spawn settings BEFORE creating the world. These settings can be modified after the creation of the world, so don’t panic.
 
So:

These settings must be disabled if you want your star system to include NPC stations, cargo vessels, and other such features. This is especially important if your star system will include NPC mods.

 
 
If you want your star system’s NPC spawns to work, the image below will help you.
 
 

 
 
 

3. Adding desired mods

We will now address your request to use mods on star systems or to add modded planets.
 
 
After you have changed the Advanced Settings to how you want them, click “OK”. This will save your changes, and take you back the New Game menu. To open the mod selection screen, click on “Mods”.
 
 
Now you can add any mods that you wish to this star system to use. NOTE: Any planet mods should be loaded before any visual mods (examples are: Milky Way Skybox, Better Looking Planets, Apothilight, etc). This will ensure that the load order is well-organized and should not cause load-related problems.
 
 
Let’s say, for example, I want to add four mod planets, a modified skybox, and the Better Looking Planets mod to make the vanilla planets look better. Here’s an example load order:
 
 

 
 
In this example, the modded skybox was placed first in the load order. The Better Looking Planets mod, which only affects vanilla planets, was placed after the skybox mod but before the actual planet modifications. This is because mods lower in order will be loaded after mods above them; if you are using modded planets, it is best to place the planets after all other mods so that they don’t get overwritten by any other mods. However, modded planets can sometimes overwrite each other and cause conflicts. This can cause the textures of the affected planet to look bad or wrong. Unfortunately, there is no way to stop this except to remove any modded planets which conflict with your chosen one.
 
 
After adding your planet mods and visual mods, any miscellaneous mods that you want the star system feature should be placed last in the load order. Before adding any miscellaneous mods to the star system, consider this: “Is this mod necessary for the star systems, or something I want to include with the star system?” Or is this optional and players can decide if they want it or not.
 
You can leave the mod out if you don’t think it is necessary. If you really believe the mod is essential for the star system’s design, then include it.
 
 
 

4. Start the world and use the Admin & Spectator controls

-Now that your mod list is complete, click “Start” to create the world. You may have noticed that planets are very large and your character very small once you’ve loaded them in. Navigating an entire starsystem with your character alone takes a lot of time. We have some special controls that will make you a god!
 
 
Skip the next sentence if the game is set to Creative. To use the full Admin & Spectator controls, you will need Alt+F10 to set the game to Survival.
 
 
Here is a list of controls and selections that you will need to be able to place the planets and move in between them.
 
 


MOVEMENT


 
F8: Activates spectator camera mode.
 
-Use WASD as normal to move around.
 
-To increase/decrease the camera speed, hold Shift, scroll up/down, respectively.
 
-To teleport your character, press Ctrl+Space.
 
F6: Returns to control of your character
 


PLACING PLANETS


 
Shift+F10 opens the Spawn menu
 
-A drop-down box is located at the top. It allows you to select “Planets”.
 
-Click once on the planet’s name to select it.
 
Use the slider below to change the size (or diameter) of the planet. You can make smaller adjustments by pressing the left or right buttons.
 
-Once you have selected the size, click “Spawn”, to place the planet.
 
Ctrl+Scrollwheel – Changes the distance that the planet will be spawned from the camera.
 
Left Mouse: Places on the Planet
 


DELETING A MISSPLACED PLANET


 
Alt+F10: Opens Admin Screen
 
-A drop-down box is located at the top. It can be used to select “Entity list”.
 
-Next to “Select” is a drop down box. It can be used to select “Planets”.
 
Below it is a list listing all planets currently in the world. Click on any planet to delete it. Then, click “Remove” at the bottom.
 
 

NOTES ON MODDED PLANET SIZES:

 
Most modded planets are a fixed size that works well with the heightmap and general terrain. Go to the Workshop page for that modded planet and search for the phrase “Recommended size” to find out the ideal size. This is the phrase that creators use 95% of all the time when listing the ideal size for a planet. Once you have found that number, you must use it to spawn the planet. If the recommended size is a range of numbers (e.g. If the recommended size is something like a range of numbers (e.g., “30km-50km”) then ensure that you spawn the planet with a size within that range.
 
 
 

5. Here are some general tips for creating a star system

Although this section doesn’t have anything that is essential, I did make my own star systems and came up with some useful tips that others might find useful. These tips can be used or not, but it is up to you.
 
 
-I like to place GPS waypoints on the planet’s edge when I place it. This allows me to measure how far I am from the planet I want to spawn. Simply move the spectator camera to a planet and teleport your character there. If your character is in the atmosphere, move it a bit further away and teleport again. Continue this process until you find the edge of the planet’s atmosphere. Next, create a GPS waypoint with its name.
 
 
If I want to create a realistic starsystem, I will think about the planets that are “hottest” or “coldest”. The center of a star systems (i.e., a planet) is generally closer to it. The hotter a planet will be, the closer it is to the center of a star system (i.e. I place desert planets, barren and lava planets at one end of my star system, pretending that it is the “hot” end. Then, I will place the other planets in accordance with their temperatures. The hot end is Earth-like planets, but not IN it. “Average” planets with no visible climate can be placed anywhere, while ice/snow planets can be placed at the farthest, making up the “cold ending”.
 
 
 

6. Finalizing the Workshop and uploading it to the Web

Now that you have placed all your planets, and created the star system as you want it to look, you can move on to the finalizing and uploading phase.
 
 
-Before you do anything else, determine which planets you want to be the “starting planet”. Skip this if you don’t care about which planet players begin on.
 
It will work fine if your starting planet is a vanilla one. It is possible that players won’t be allowed to respawn on it if it is a modified planet. This can be ignored if your star system is for creative mode. If your star system is meant for survival mode, you can test this by pressing Backspace and respawning. Make sure that the planet you wish to use as your starting planet is listed in the spawn locations list. You have two options if you don’t see it on the list: 1. Make sure you add it to the list. You may need to find another modded planet if you are looking for a particular type of planet to be your starting planet. 2. Place a “respawn shelter”, on the desired starting planet, and set the medical bay/survival kits to “Share With All”. If you have created a faction that you want the players to join when they enter the star systems, choose “Share With Faction”.
 
 
-After you have completed the above, save your changes and exit to the main menu. Click on the Save button to open the Load menu. Then click “Edit settings”. You can rename the save to whatever name you like for your star system (e.g. “Zork-98 Star System, Vanilla”, “The Zork-99 System, Mods required”)”, etc. Go to Advanced Settings once more after renaming. You can ignore any settings that were before it, such as Online Mode or Max Players counter. These settings can be modified by players using the star system.
 
 
-In Advanced Settings, make any changes that aren’t what you wanted it to be. Things like the world limit, view distance, day duration, block progress, and the day duration. All of these settings can be modified by the player using the star system in any save, just like any other save. You will want NPC spawns in your world. Now is the time to go back to Step 2.5 and ensure that all the settings are enabled. You can leave “Enable economy” off if you don’t need NPC stations. Set them to go if you want spiders or wolves. Continue on. Once you’ve set the Advanced Settings as you prefer, click “OK” to return to the Load Game menu. Now we upload!
 
 
Click on the save that contains your star system and then click “Publish”. You will be asked to attach any tags and select the location where you want it to be uploaded. Once you have made your choices, click “OK”. The Workshop page should now be opened in your Steam browser.
 
 
-From the Workshop Page, you can edit the description, add video previews and videos, add required items, change visibility, and so on. These can be modified but not required. If you want people to get a better understanding of your star system, give it a detailed description. You can also add preview images. You must go to “Add/remove required items”, click the tab “Subscribed Items”, and add all mods that your star systems uses. Without this, players won’t have the ability to see which mods are needed. To return to the Workshop page, click “Save and continue” at the bottom-right. If you don’t have anything else to do, make sure visibility is set at “Public” or any other option you choose. Congratulations! You have uploaded your custom star system! 😀
 
 
 

Epilogue?

Some other things I haven’t included in this guide include tips on how to get nice preview images, good formats and descriptions of the star system, and how to make custom thumbnails. These are not important and you can find many lists on the forums and guides. I will leave you with a few final points.
 
 
-To test your star system after it has been published to the Workshop, go back to the main menu and click “New Game”, then “Workshop” to find your star system. Start a new game. You may get an error message from the game saying “World already exists!” Download and overwrite? This error occurs because the save file that you uploaded to the Workshop is still in your saved games list and has the same name of the game you are trying to create. It is best to go back into your saved games and rename the original file to something like “Zork-99 System *ORIGINAL UPSLOAD*”. Then you can create a new game using your star system and start playing it!
 
 
If you decide to make changes, you don’t have to start over unless you are adding/moving around other planets or changing things like the asteroid density. You don’t need to start over again. Simply load the original save file, make any necessary changes, save and exit, then click “Publish” again. This will update the Workshop page using the modified save file. It will also keep the description, images, and other details. You originally used for the page.
 
 
-If your star systems uses modified planets, credit them in the description of your Workshop pages! This is standard Workshop protocol! It is fine to credit multiple creators. A blanket statement like “I didn’t create this star system mods”, is acceptable.
 
 
This should cover everything you need to know in order to create your custom star system. If you have any questions or need clarifications, please leave a comment. I will do my best to answer your question.

 
 
I hope you enjoy the Step-by-step guide for making a custom star system – Space Engineers guide. This is all for now! If you have something to add to this guide or forget to add some information, please let us know via comment! We check each comment manually!