Getting started creating mods using GECK

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The following information is primarily taken from the Help starting out thread on the "Fallout New Vegas GECK and Modders" forum. The information is preserved here as an alternative to searching through back posts in that forum for commonly asked questions.

This article provides a learning roadmap, a starting point and guide to progression; not a tutorial. Consider it a collection of suggestions and links to more detailed tutorials, articles, videos, and tools.

There is a lot of unique vocabulary related to creating mods in the following material, such as the distinction between "meshes", the 3d framework of objects (saved as Nif files); and "textures", the surface "skin" over the "mesh framework" (saved as DDS files). The Elder Scroll Texture Guide (TESTG) site has a glossary and several pages devoted to explaining these to new mod creators and users. Rather than explaining them here, please reference that site when you need clarification.

Tools and Programs

  • Garden of Eden Construction Kit (GECK) (freeware.) The official "game editor" for Fallout 3 and New Vegas.
  • GECK 1.4 Powerup (mod.) Comes in a "standalone" version for the "vanilla" GECK functions, and one for GECK with NVSE functions. It fixes and improves some issues while providing the missing messages when the GECK compiler finds an error or warning, and lets you save a script without compiling it. Considered "essential" by experienced mod creators.
  • Blender v2.49b (freeware.) this download includes ALL related files and compatible versions. This is the "complete" package for creating meshes for Bethesda games; including Python, the NIF scripts, and the "Noob to Pro" PDF tutorial. Check out the "Optional" files section for some additional functionality.
  • NifSkope (freeware.) A graphical program that allows you to open NIF files, view their contents, edit them, and write them back out again. You can use it to quickly make changes to specific properties of a NIF file such as changing the texture, adding translucency, and more. A 3D view of the contents of the NIF file allows you to preview your changes instantly. You can even create texture templates, and import & export OBJ files. (Note a fully compatible version of this tool is already included in the Blender v2.49b package linked here.)
  • 3DS Max (1 month free trial, $185/month or $1470/year subscriptions, 3 yr student/educator license.) Commercial product by AutoDesk but the version that works with Nif files isn't free. Versions after 2013 don't seem to work with at least Fallout 4 (according to this thread) using the included official NIF exporter, though there is an unofficial "Figment" exporter plugin fork on GitHub which does seem to work.)
  • Maya (1 month free trial, $185/month or $1470/year subscriptions, 3 yr student/educator license.) Animation, modeling, simulation, and rendering software by AutoDesk.
  • NifTools Wiki (3D package plugins for "3ds Max", "Blender", and "Maya" modelling tools.
  • Paint.NET (freeware.) Image and photo editing software for Windows, originally based upon the Paint program included as part of Windows, but with many enhanced features such as "layers", special effects, and unlimited history ("undo"). Require Microsoft's .NET Framework 4.6+.
  • GIMP: GNU Image Manipulation Program (freeware.) a cross-platform image editor available for GNU/Linux, OS X, Windows and more operating systems. Provides extensibility through integration with many programming languages including Scheme, Python, Perl, and more. The result is a high level of customization as demonstrated by the large number of scripts and plug-ins created by the community.
  • CIPSCIS Script Validator Allows you to quickly indent your script while simultaneously checking it for several errors, many of which are not picked up by the GECK's compiler. It works with Skyrim, Fallout 3, and Fallout New Vegas. Includes it's own tutorials.


Basic advice is to start with the game Construction Set/Editor (this is usually a separate download, not included with the game installation). There is going to be a wiki page for it with tutorials to help get you started, but note that there are unspoken assumptions that you are familiar with concepts introduced on the "Construction Kit"/"game editor" wikis for earlier Bethesda games such as:

(TES5: Skyrim came after all of those (2011) and uses a different variation of the game and script engine.) So, don't neglect those older wikis as resources. Where there appears to be a conflict, assume the later wiki or the one specific to your game is correct.

In addition to the Construction Set/Editor, you'll probably want to get community created editor enhancement tools, like the "GECK PowerUp", "Oblivion Construction Set Extender", etc. These allow you to perform actions not included in the default editor, like edit ESM files without converting them to ESP first, and may also give you better debugging for scripts. These capabilities vary by the tool. On the negative side, such extensions may also annoy the heck out of you with error messages, many of which you don't need/understand and don't care about. But they are always worth looking into.

There are also conversion tools which are required to export the 3-D models from your modeling tool into the "NIF" format that Bethesda games use. It is very important to note that the import and export tools only work with certain versions of modeling programs. For Blender, you need version 2.49, which is older than the current version of Blender. The Nexus Oblivion mod Blender linked here is a package that has Blender v2.49 plus all of the NIF tools and includes NifSkope, all of which are the correct versions to use together. You will save yourself a lot of trouble if you install everything from this one package. If you don't, you can run into version problems and things will never work right. Instructions on the correct way to install this combination of tools can be found here. (Note where there seems to be a discrepancy in version numbers, stick with the version included in the package.)

"Script Extenders" (SEs) are plugins to the game editors that provide additional functionality features, and were created by the gaming community to overcome perceived shortcomings. Mods the use even one of those SE functions need to specify that the particular SE is now a requirement.

Item (armor, weapons, buildings, etc.) construction and customization requires learning 3D modelling, which is NOT a quick process. You are going to invest a lot of time and patience in learning your tool of choice. The three most common tools used are Blender, "3ds Max" (aka "Max"), and Maya. There is very little discussion about Maya in the forums related to Bethesda games because while it is considered the better choice for animation, "Max" is simpler to grasp and less daunting. Both "Max" and Maya are considered "industry standard" tools, and both will do the job. See these articles for more in depth comparisons if you are going to invest in learning either product:

The "workflow" on Blender for Nif files is considered more complex than with the others because it often takes you into the Nifskope tool, but read about the Nif Exporter plugin for Max issues in that entry. It is necessary to use the correct version and tools that work with that version of any of these products.

Because it is "free" and the others are quite expensive for most people, Blender is usually at least their first choice. "Blender Noob to Pro" is a good resource for 3d modeling using Blender, and is included in that package linked below.

For texturing your 3D models, you'll need something that can handle ".dds" files. GIMP and Paint.Net (which is not the Paint that comes with Windows) can both handle ".dds" files. Paint.Net comes with ".dds" support built-in these days. GIMP still needs a plugin. Which program you use is more a matter of personal preference than anything else. Some find GIMP a bit more difficult to use but it also can do some things that Paint.Net can't do. Paint.Net on the other hand is, in the opinion of many, more intuitive and easier to use. Although, now that Paint.Net has a proper normal map generator that actually works available as an add-on, GIMP use tends to be even less frequent now. A lot of it is personal preference, though. Some folks just like GIMP better. Both programs work fine. You can also use Photoshop, but that's not free.

Once you have the 3-D model textured (UV mapped) and maybe have generated a normal map for it as well, then you need to export everything. Blender and the NIF tools don't export a lot of things properly, so then you have to go into NifSkope (which comes with the NIF tools) and fix it. (The proper weight of "bones" in skeletons, along with "shader flags", is almost always wrong, for instance.) Be sure to check that the path given in the mesh to the texture file is in "relative" format. (See How to fix hard-coded texture paths in NIF files.) The default format of the mesh editor's paths may not be "relative".

Once that is done, then go into the game specific Construction Set/Editor and add your custom items to whatever mod you are working on.

Getting back to the GECK, there are a few things that are broken in it. It ships with a spell checker but doesn't include the dictionary, so that's just annoying. If you use the GECK Powerup you can uncheck the spell checker and disable all of that annoyance at least while you are editing your mod. Unfortunately it won't remember that setting and you'll have to uncheck it the next time you edit your mod as well.

Another thing that is broken is the "lip generator" for dialog. If you have Skyrim or Oblivion you can copy their lip generator from the "sound\processing" folder to GECK's. If you have all of your voice files in place and they work already, in the GECK all you need to do is bring up that dialog in the quest editor. Your wav file should show up down near the bottom, where it says voice type, mp3, wav, lip, ltf, and path. Click on that to select it, then click on the "from wav" at the bottom. The "generate lip file" option should now become active and you can click on it. Note that the GECK will not update the information on the screen, so it will still have an N under lip file even after you have generated it. Close that dialog option and re-open it and then you should see a Y under both the wav and the lip. If you record the voice files directly into the GECK (using the record button at the bottom of the dialog window) then when you press save it will automatically generate both the wav and the lip files.

Custom items

Plan to start by making simple mods: like maybe adding a house somewhere. Then make simple retextures of existing objects. If you get that far, then you are ready to start making your own "mesh" models.

If you are making armor or a weapon, the most commonly suggested advice is to start with an existing version that is similar to what you want. That way you'll have an existing model to base your 3d model on that is close to the right size so you can scale your new model appropriately. Depending on what is desired, for armor it is suggested to often start with just a body model instead. Once you've created your model, you will have to "parent it" to the appropriate armature (aka "skeleton") in order for it to work. If words like "parent" and "armature" in this context don't mean much to you, then you need to do more reading about 3d modeling (again, "Noob to Pro" is a good resource for Blender).

Things like buildings and clutter items are also created with Blender (or 3dsMax), but they don't have armatures. They do have collision though. You'll have to make a collision mesh in Blender when you create your model.


If you want to create your own worldspace, then you must be a real glutton for punishment, because this gets you into the buggiest parts of the GECK. For example. you create a worldspace, then go and edit its heightmap, and when you save your heightmap and exit out of it, the GECK will crash. The only way to avoid this is to create your worldspace, save your mod, exit the GECK, reload your mod, and then edit the heightmap. This isn't explained anywhere in the GECK, but if you create a heightmap that is too low, the GECK will crash. I used to create heightmaps with a general offset of about 6000, but then I found there's another bug that when you do that, trees don't generate LOD properly. So your heightmap really needs to be above something like 20,000 or so. The list of bugs that you run into with worldspace generation goes on and on like this. Worldspace generation is MISERABLE. There's a reason you don't see many worldspace mods and many of the ones you do see use a flat worldspace with landscape objects like cliffs and rocks instead of a true heightmap to generate the landscape.

New worldspace creation is pretty much the same from FO3 to FNV, so tutorials for FO3 are okay for you to use. there don't seem to be any good tutorials. Most have pieced together bits and pieces from various tutorials and just plugged through it until they figured it out by trial and error.

Some tutorials make it sound a lot easier than it is. If you are making a very small worldspace, it can be done fairly quickly. But if you are making a larger worldspace, it becomes a very slow and tedious thing.

Also, the worldspace parts of the GECK are among the buggiest and most difficult to use parts of the toolset. Save often, and make backup files often just in case the GECK totally trashs your mod and you need to revert to an earlier version.

Here are some tips on getting past the first initial problems, which will give you an idea of how frustrating this can be.

The first step is just creating the world space. Click on "World | World Spaces" in the GECK, and when that form comes up, just click "New" on the left hand side to give your new region a name, and fill in the blanks. Exit out of that, and save your mod, because the next step will usually crash the GECK.

The next step is to create a "heightmap". A lot of people skip this and make small, completely flat world spaces, and use things like cliff objects to do the majority of their landscaping. That's okay for things like a small base surrounded by mountains or something like that, but if you are trying to create a town or something it looks amateurish.

Warning - If you basically default the heightmap settings, it will crash the GECK. Seriously, sometimes it seems like the GECK is a Vault-tec experiment designed to test modder frustrations. The reason for this is that the GECK doesn't like it if the landscape is too low. So the first thing some do is create a random landscape that doesn't have much randomness to it, so that what it ends up doing is creating a basically flat landscape. The settings successfully used under the random generator are a frequency of 100, an amplitude of 50, and a base offset of 6000. The base offset is extremely important since if you don't set it high enough, the GECK crashes.

Some folks use things like "geological survey data" to generate their heightmaps. If you poke around on the forums you'll find the basic procedure for it.

If all is well so far, save your heightmap and save your mod. If you didn't restart the GECK earlier, chances are that right here is where the GECK will crash. The second time through this it usually works.

Now re-open your heightmap, and use the editing tools to create your mountains, rivers, lakes, etc. You can play around with the default water settings in your worldspace to get the water to line up with where you want it on your landscape. If you used a base offset of 6000 when creating the heightmap, a water height of about 3500 tends to work fairly well. When you are editing the heightmap, make very small changes. If you make changes that are too drastic, you basically tear the landscape and the GECK can't figure out how to fix it and it ends up with a broken landscape that either crashes the GECK or crashes the game or both.

What you probably have at this point is a landscape that has mountains and plains and rivers and lakes and whatever. Save your heightmap and save your mod. If you were to go and look at it though, it will probably be very flat and unrealistic looking. You can add in some randomness to your heightmap to fix that. The settings that some tend to use are a frequency of 2000, an amplitude of 200, a base offset of zero, and this is very important, make sure you click "additive" and "subtractive". If you don't check the "additive" and "subtractive" boxes, it will create a new random heightmap instead of just adding a bit of randomness to your existing heightmap. Now you should have something that looks a lot more realistic. Again, save your mod. The GECK likes to crash for no good reason a lot when doing worldspace stuff.

Now you can go to your "cell view" form, and change "interiors" (where it says "world space") and select your new world space. It will put you right in the center of your new world space. And you'll run into yet another GECK bug. If there is nothing on the landscape, and the GECK hasn't ever focused on any kind of object, the GECK will usually display water instead of your landscape, so you end up looking at a big solid grayish-green blob on your render window instead of looking at your landscape. If this happens to you, select "interiors" in the "cell view", double click on some static object, let the render window display that cell, then go back to your new world space. Sometimes just moving around using the arrow keys will get the water blob to go away once you move far enough to change cells. Once you have objects in your new worldspace you won't have this problem any more, as long as you first go to an area that has objects when you select your new worldspace when you start up the GECK.

Now you can tweak and paint the landscape to your heart's desire, and add objects and do all of that fun stuff. Unfortunately, you have only two basic tools for editing landscape. You can use the "landscape editing" function in the "render window", which limits you to a maximum brush size of 15, or you can use the "heightmap editor". If you are trying to make something the size of a small pond, the "landscape editing" makes you feel like you are carving out Mount Rushmoor using a hand chisel, and using the "heightmap editor" makes you feel like you are trying to do brain surgery with a chainsaw. There's nothing in between. The "heightmap editor" is also a bit quirky. It tends to leave big black square splotches just outside of the view on your render window, and those don't go away when you close out the heightmap editing box. Even if you move away from that area using the arrow keys, the splotches stay there. You can only make them go away by selecting another area from the cell view and then going back to the area where you were.

Buggy buggy buggy. That's the GECK.

There's an auto navmesher, but that is buggy as all heck. Some have found that it works reasonably well on wilderness landscapes containing simple objects like trees and cactuses. It often completely fails when the cell contains SCOLs ("static collections") and doesn't work well at all if there are a lot of complex objects inside the cell. That means that you end up having to hand navmesh a lot of cells. If your new worldspace only has a few usable cells, this isn't a big deal, and you can navmesh all of them in a few hours easily. A worldspace has basically 64x64 cells, which is 4096 total cells. You can auto navmesh three or four cells per minute, and once you get experienced at navmeshing, you can probably finish a fairly complex cell in a few minutes. If you figure an average of one cell per minute (being a mix of hand navmeshed and auto navmeshed), that's 4096 minutes to navmesh the entire worldspace. That works out to a bit over 68 hours. If you navmesh for three hours per day (because you have a job or go to school or do something that takes up the rest of your day) then it will take you roughly 23 days to navmesh the entire worldspace.

The auto navmesher will often not navmesh across roads. However, it will usually navmesh through fences. So be prepared to hand navmesh any cell that contains a road or a fence.

Use the "b" key in your "render window" to show "cell boundaries". You'll want to arrange buildings and structures and other things so that you can easily do the navmeshing. You wouldn't want a building's door to be straddling a cell boundary, for example.

There's also an "auto generate navmesh" button under "regions". Don't use it. It is very very very very broken. Some have made it work under some circumstances but it is incredibly buggy.

LOD generation is similar. It's not too bad if you only have a few cells, but for a large worldspace it takes darn near forever.

This is why you need to decide ahead of time if you want to create a tiny worldspace that you can finish in a short amount of time, or if you want to create a major sized worldspace that will take you a huge chunk of time to complete.

There's a reason that you don't see too many mods with worldspaces on the nexus. It's difficult to figure out, and buggy as all heck. It also takes a huge amount of time, which is why the few worldspaces that you do see tend to be small and simple. It is not uncommon for a single mod creator to spend so long working on a mod with a new worldspace that the vast majority of that game community has moved on to another game.

One other thing. If you do try to make a huge worldspace, you can use the regions to add a lot of landscape items like cactuses and trees. This is a huge time saver, but be forwarned. If you have ever clicked on an object in debug mode, you'll notice that the object has an 8 character ID, something like 4100D236 (a completely made-up number). This is a hexidecimal number. The first two digits will be the number of your mod (41 in this case), aka its mod index. Fallout gets 00, and the different mods are assigned numbers as you add them into your mod list. On a system with the official DLC, "Dead Money" is 01, "Honest Hearts" is 02, "Old World Blues" is 03, etc. You can see the mod index in most mod managers. So if you add another mod and it ends up loading before this one, that 41 could get bumped up to 42, for example. Now here's the important part. That xx00D236 part means that you have a six digit hex "form" number for the ID. This corresponds to the file offset in your mod. The largest 6 digit hex number you can have is FFFFFF, which is 16,777,215. A worldspace will take 10 to 12 megs just for the heightmap and landscape, not including navmesh and texturing. If you go over the 16 meg limit and add an object, you brick your mod. The GECK will give you no errors at all when it saves your mod, but when you try to load it again, it will lock up the GECK. That means you can't use the GECK to fix it. Hope you have a backup of your mod from earlier somewhere, because that's the only way out of it.

If you are making a small worldspace, then you probably don't have to worry about this at all. If you are making a large worldspace and are adding tons of landscape objects (cactuses, trees, etc) then you can run into this limit and it will break your mod. So if you are going to do a worldspace, do the landscape first, then add all of your objects, NPCs, creatures, etc. to it, and THEN do the navmeshing and texturing last as those don't care about the 16 meg boundary issue.

Additional Material

The following is not intended to be a complete list, but rather a starting point on articles and videos specific to FNV to assist new mod creators in getting started. Bear in mind that articles in older games may also be of assistance with basic concepts as long as ou adjust to the pecularities of the syntax in the GECK.

These articles are not intended as "tutorials", but do convey useful information to the mod creation process.


Some tutorials are specific on making various kinds of Fallout NV mods with GECK. Others cover aspects of creating mods that are more appliable to mod creation in general. Always bear in mind that the game engine for Skyrim and Fallout 4 is different than that used for older Bethesda games, and each game version of the engine is different in some way.

Video Tutorials

Tutorial Articles


Nexus wiki articles referred to by this article:

Nexus wiki articles that refer to this article:

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