These are listed approximately in the order in which you might encounter them.
So ones about creating a level are first, then problems editing a level, then playing a level, then making a goomod... and so on.

[ I clicked New Level and...]       [ I clicked Play and... ]       [ How do I... ]

It's asking me to select a folder to edit. Which folder should I choose?

Actually that's a personal choice, but you should NOT (NEVER EVER) edit the original WorldofGoo game folder!
The popular choice is just to edit your Gootool "modded" folder. This will usually work fine, but there a couple of things that can catch you out.
Like - If you run GooTool with an old version of your level enabled... it'll overwrite any changes you have made.
For this reason some people prefer to create yet another World of Goo folder just for editting purposes.

I clicked New Level and...

...It won't let me have spaces in my level name. Why?

The level name you enter when you first create/clone a level is actually the folder name.
For compatability with other platforms you are not allowed to include spaces.
The name that will appear on the title screen for your level, and the addin name, are separate and can both be set in the Addin tab, and do allow spaces.

... I enter the name, click OK and it comes up with a error. Why?

The most common cause of this is lack of "permissions" or "rights" in the WorldofGoo folder you have selected to edit.
To create new level, or clone existing ones, you must be able to create folders, and read / write / create / delete files, under the main folder you are editting.
Try creating a new WorldOfGoo folder in "Your Space" (My Documents / Home Directory or whatever) or on a separate drive.
Then use Change World of Goo Directory from the file menu to select the new folder.

...What are these greeny/blue boxes?

They are representations of camera positions and POI's [Link to Camera's and Pois].
To begin with you won't need to worry about them at all. In fact, you're probably better off just hiding them. Use Hide Camera/Poi's on the top toolbar.

I've added a SceneLayer, but I can't enter anything into the "image" property. Why?

Before you can apply an image to a SceneLayer (or a rectangle or a circle) you must have imported the image into the Resources list.
Use the Import Images button on the top toolbar.. find the image files you want, select them and click Open.
They will now appear in the Resources Tab, and when you type something into an "image" property you will get a list of all the available images. Pick one.
If the one you want isn't there, go and import it as well.

I can't see the Goo strands (or other things in) in my level.

The main cause of this is having a background image set to depth = 0.
Strands are always at depth of 0 so if the background image (or any image) is also set to depth=0 or more, it will cover them up.
You should always set your background images to a depth less than 0 : -1 will do, but -100 or -200 is usually better.

I clicked Play and...

...It starts the game normally and I can't see my level anywhere.

To play levels directly from the Editor, Windows users need to upgrade to v1.3 of the game.
Patch Available here ->
Note: If you are editing your "modified" folder ( which you should be ) then you will need to run GooTool and click Save after you apply the patch. This will copy the updated files into your modified folder as well.

...Nothing happens.

This is usually because the game has crashed, and is still open and displaying the "Fatal Error" window.
Close that window, and try again.

...It shows the Title screen and then just stops. What's wrong?

There are lots of ways to crash the game, and we're finding new and interesting ones all the time.

Are you using the latest version of the Editor?
Check Here [ Download Page ] We try to add protection and checks for as many of these problems as we can, so the latest version of the Editor may be able to tell you what's wrong.

Try loading one of the Original levels
But don't make any changes, and just click Play. If that doesn't work, then it's something about your system... post in the forums. If the original level works fine.. but yours still doesn't, then the problem is something in your level.

There are a few things we can't detect, warn about or prevent
So may be it's one of those... check the list below.

Missing Ball resources
If you have used a custom Gooball in your level, and it uses a custom image or sound and the file isn't where World of Goo has been told it is... the game Crashes

Missing Custom Particle Effects
If you have used a custom Gooball in your level, and it uses a custom particle effect, and you don't have the addin that Goo came from installed and enabled at the moment.... the game Crashes

If you checked all the above problems...


You've might have found a new bug / weakness / problem with World of Goo that no one else has found / reported.
Your best bet is, make a goomod of your level.. upload it somewhere, then post for help in the forums. We're always interested in finding new ways to break the game, so we can add protection into the Editor and stop it happening again.

I clicked "End level" and the game crashed... what's the problem?

Yup, it does that.. we don't know for sure why, and we can't stop it.
If play through the Editor and you finish the level "properly" and click the Continue Handle.. the game ends fine.
If you quit by using "End Level".. the game crashes.. just close the Fatal Error Window and carry on editing.

It says my Addin Id is invalid... what is valid?

To be safe, always make your Addin Id something like com.goofans.YourName.LevelName
If you're interested... the rules are...
It can only contain letters, numbers and . (dots) No spaces or other symbols are allowed
It must contain at least one . (dot)
It cannot start or end with a . (dot) and cannot have .. (2 dots together)
If you're REALLY interested... RegExp: ^([a-zA-Z0-9]([a-zA-Z0-9]+)?\.)+[a-zA-Z0-9]+$

How do I...

...Set OCD for my level?

OCD is set in the Addin tab under Levels -> Level -> ocd
If you do not see an ocd entry, right-click Level in the tree, and choose 'Add child ocd' from the menu.
Note: You can never get OCD when playing directly through the Editor...
Sure you can meet the criteria.. but it won't go "ooohhh.. OCD!"