UDK Frequently Asked Questions

Document Summary: This is a list of Frequently Asked Questions and Answers.

Document Changelog: Created; maintained over time.

General

Q: Can I create any kind of game with UDK?

A: Absolutely! UDK is the perfect solution for any kind of virtual world you wish to create, from racing games to simulations. Visit our Showcase to see some of the amazing creations our users have authored with UDK.

Q: Will my UDK program run on Mac, iPhone, PS3 or Xbox 360?

A: As of right now, UDK is a Windows-only program. Please drop by from time to time to see if we've announced support for other platforms.

Q: I’ve been making mods for Unreal Tournament 3. How does UDK differ from the UT3 editor?

A: You can create standalone applications with UDK. This means that users will be able to install and run your game without owning a copy of Unreal Tournament 3.

To learn about the upgrades and major feature additions included with UDK, check out the build upgrade notes at UDN.

Q: What are the minimum requirements for UDK?

A: Here are the minimum and recommended requirements...

Minimum:

• Windows XP SP2 or Windows Vista
• 2.0+ GHz processor
• 2 GB system RAM
• SM3-compatible video card
• 3 GB free hard drive space

Recommended for Content Development:

• Windows Vista 64 SP2
• 2.0+ GHz multi-core processor
• 8 GB System RAM
• NVIDIA 8000 series or higher graphics card
• Plenty of HDD space

Q: How much knowledge is required for someone to make a project with UDK?

A: If you are using Unreal Engine 3 for the first time a good place to start is the Unreal Developer Network. You can visit UDK’s home on UDN here: DevelopmentKitHome

And the Getting Started with UDK portal on UDN is here: DevelopmentKitGettingStarted

There are also new “Mastering Unreal Technology” books, authored by 3D Buzz and published by Sams.

Two volumes are currently available:

• Mastering Unreal Technology, Volume I: Introduction to Level Design with Unreal Engine 3
• Mastering Unreal Technology, Volume II: Advanced Level Design Concepts with Unreal Engine 3
• Mastering Unreal Technology, Volume III: Introduction to UnrealScript with Unreal Engine 3

UDK is aimed at anyone who wants to work with Unreal Engine 3, and UDK provides the same professional, world-class tools with which our developers work. UDK isn't watered down in any way so both beginners and professional developers can use it.

Q: How is developing UDK different from making mods?

A: Every time Epic ships a major new PC game, we ship the Unreal Engine tools with it and the mod makers blow us away with their creativity and ingenuity.

What makes UDK different is that it can be used by everyone. You don't have to own a copy of “Unreal Tournament 3” or “Gears of War” to get access to the engine tools, plus we are continually releasing free UDK updates.

In addition, all UDK releases are standalone products, meaning anyone can release a totally free game that requires no additional software.

Features

Q: How do I know what features are being worked on or when a feature is released?

A: UDK Builds are typically released monthly. The UDK Build Upgrade Notes details the latest features and updates.

You can download the latest version from the UDK Download site.

Q: What about localization and international support?

A: The UDK software is available in the following languages: Chinese (Simplified), English, Japanese and Korean.

We're in the process of translating the UDK web site into Japanese, Korean and Chinese. Those languages are already supported in the UDK toolset itself and on UDN.

Q: Can I write C++ code that works with UDK?

A: You can interface C++ source via TCP. Basically, you can use UnrealScript and TCP/IP as glue code between the engine and your native code. For more information, visit the Unreal Developer Network here: TcpLink

The December 2009 UDK Beta adds the ability for UnrealScript to call functions implemented in a Windows DLL. For more details, visit DLLBind.

Licensing

Q: Is UDK really free for me to use?

A: Absolutely. Download UDK, create your project and distribute it completely free of cost.

Q: Can universities, high schools, faculty and students use UDK for free?

A: Educational institutions can use UDK under our "FREE for educational and non-commercial use" policy, even though they're charging tuition, and we'd love to have you teaching Unreal Engine 3 as well. No license is required for faculty or students.

Your students are encouraged to use UDK inside or outside of school to learn game development and for any other non-commercial purposes.

If a student, for example, decides he wants to sell a game he made as a school or hobby project he is welcome to do that as well. He would need to purchase our $99 license and then pay us royalties of 25% of his earnings after the first $5,000 he makes.

Q: Can I release a UDK game as open source?

A: The rights to develop and release a game for free are contained in the end-user license agreement (EULA). The EULA is also the license that governs the release of your game as it's built on UDK. You can't release your UDK project under terms other than the UDK EULA (like GPL, LGPL, open source, etc.). You don't have the right to encumber the UDK with terms that we have not already granted to you.

Q: How does this differ from an Unreal Engine 3 license?

A: The primary difference is that UDK does not include Unreal Engine 3 C++ source code access. UDK ships with all the UnrealScript code and Unreal Engine tool integrations as the commercial version of Unreal Engine 3, offering all the same features the pros use.

The tools and technology are the same however a "full" license includes the underlying C++ source code to the engine and tools, which allows licensees to make virtually any change they want and potentially ship their game on consoles provided they're licensed by the console manufacturer.

Both UDK users and traditional Unreal Engine 3 commercial licensees have access to all UnrealScript source code. UnrealScript is comparable to a programming language like Java in terms of features and performance (byte-compiled), with features designed to simplify game development, e.g., state scoping of functions, automatic serialization, simple system for defining networking replication of properties and remote functions, etc.

There are tons of great materials and support avenues for UDK users, including the two new "Mastering Unreal Technology" books from Sams, hundreds of pages of support items on our Unreal Developer Network , UDK Community Forums, and hundreds of hours of free video tutorials from the folks at 3D Buzz with a whole bunch more tailored specifically to getting started with UDK in the works right now.

Full UE3 licensees also get direct support from Epic's engineers who write UE3 code.

Q: May I license UDK for iPhone?

A: Unreal Engine 3 for iPhone 3GS and iPod Touch is an R&D Project that is still in development. There is no licensable product for UDK.

For more licensing-related questions, please see the UDK licensing page.

Business and Legal

Q: Is it possible to create custom plug ins or tools for the engine?

A: Absolutely. No addition license is needed. If you reference the Unreal Development Toolkit or UDK by name you must make sure any Epic gets appropriate legal attribution* and the work is clearly labeled "not endorsed by Epic Games"

* Unreal Development Kit (UDK) © 2009, Epic Games, Inc. Epic, Epic Games, Gears of War, Gears of War 2, Unreal, AnimSet Viewer, AnimTree Editor, Unreal Cascade, Unreal Content Browser, Unreal Development Kit, Unreal Editor, Unreal Engine, Unreal Kismet, Unreal Lightmass, Unreal Matinee, Unreal PhAT, UnrealScript and Unreal Tournament are trademarks or registered trademarks of Epic Games, Inc. in the United States of America and elsewhere. All other trademarks are the property of their respective owners.

Q: Could I set up a website and put games onto it, but not sell the games, just make money through ad sense?

A: Collecting revenue from ads on a site designed as a portal to your UDK based games doesn't make your games free. It just acts as a proxy to direct revenue collection from your UDK applications. If you are collecting ad revenue as a proxy to collecting direct revenue from the game you will require a commercial license and Epic is due a royalty.

Q: In what intervals are the royalties checked? monthly? quarterly? yearly?

A: Quarterly, no later than 45 days after the end of each calendar quarter.

Q: Teams out there have made total conversion mods for UT3. Could those teams now move their files over to UDK and export a stand-alone game?

A: This is already happening - see The Ball, Prometheus, and soon The Haunted. Note that these mods do not use Epic's UT3 assets. They are built entirely with custom assets.

Q: Can we use SpeedTree models compiled by the SpeedTreeModeler freely in our game, or we have to pay SpeedTree for that?

A: You are free to use the Speedtree models included in the UDK in your UDK application.

Q: What's the definition of ""release UDK code""? Is using udk code, eg extends a class from UTGame, included? Or it's only prohibit publishing UDK source code?

A: This means you cannot release your UDK application (code and content) under terms that we did not grant you. For example, you may not release your UDK application into open source or under a GPL, LGPL type license as we do not convey the rights to you to do so.

Q: ""...under a license that is not from Epic Games"" Does that mean if you do obtain license from Epic Games, (eg, the 25% royalty commercial license of UDK), you can freely use the content packaged with UDK?

A: This means you cannot release your UDK application (code and content) under terms that we did not grant you. For example, you may not release your UDK application into open source or under a GPL, LGPL type license as we do not convey the rights to you to do so.

Q: Bink Watermark is annoying. Why is that there?

A: It's part of the value Rad Tools gets from allowing UDK users use Bink for free. If you would like to remove the watermark please contact mitchs@radgametools.com to discuss watermark free Bink license terms.

Q: Console Games?

A: The UDK currently only supports PC: Windows. We are reviewing various platform options. We're keen to support consoles with the UDK but will require support from the console manufactures. The only licenses we have to support Xbox 360 and PS3 development at this time are our full source licenses.

Q: I just want to be clear on the royalty side: 25% is on Net earnings by the developer, correct? Not Gross sales on portals I hope.

A: The 25% royalty is calculated on the revenue the UDK licensee receives by commercializing their UDK application. It will be defined in the Commercial Amendment to the EULA to "includes, but is not limited to, revenue earned from: sales, advertisements, sponsorships, endorsements, subscription fees, rentals, pay-to-play, services you sell or are remunerated for in connection with the use of your application and amounts a third party pays You to develop or use the application."

Q: Architectural Visualization Info

A: Go for it. Please refer to the license terms here (http://udk.com/licensing.html) for the appropriate license if you are going to develop architectural visualizations for commercial gain.

Q: If a royalty bearing license is purchased, will I then be able to access the red links in the UDK Documentation Section?

A: No. The red links are for source licensees only. The red links contain information that is either confidential, or (in the majority of cases) is only relevant to a licensee with source code access. We've already made a large number of UDN documents public as a result of user feedback. Please post a request in the Documentation forum if there is a specific document you would like to see made public.

*Q: Does a commercial UDK license agreement include access to documentation on UDN that requires a login? *

A: The areas of UDN that require a login are for Unreal Engine 3 source code licensees only. This information does not pertain to the UDK.

Q: If an indie dev makes a successful game and sells a lot of copies. Can they always buy a professional license and avoid the 25% Royalty. (i.e. if it proves cheaper). Or does the UDK use bind the current project to the UDK license terms?

A: Of course, we are happy to discuss full source licenses with you

Q: Sinsoft hosts ads on sinsoft.com (and maybe sinsoft.net), but the ads have nothing to do with the UDK. In other words, they are ads on our main website. Does ad revenue share refer to ads being displayed inside the game engine (i.e related to UDK)? or any ad revenue?. Does Ads on websites relate to UDK? What is UDK related ad revenue mean?

A: If you are collecting ad revenue as a proxy to collecting direct revenue from the game you will require a commercial license and Epic is due a royalty.

Q: How is revenue calculated for the purpose of calculating the UDK royalty?

A:Your UDK royalty is only calculated on revenue you receive. If your UDK app generated $100.00 of retail or online sales but you are paid only 70% due to a 30% distribution fee your UDK royalty is calculated on the $70.00 you actually received.

Q: If I make a .udk level file, which contains no UT3 assets but only custom made content by me, I'm not allowed to share that .udk file with anyone else?

A: There is nothing in the UDK EULA preventing you from freely sharing your custom, original work with others.

Q: Can we create a game extending from UTGAME code and sell it for commercial purposes or is this considered part of the "assets" of the UDK that they do not want us to use?

A: UTGame script code is not consider part of the restricted asset set. You may freely use it in your UDK application as you see fit.

Q: If I port my UT3 total conversion mod into UDK successfully, but my custom weapon's code is largely identical to that of the Translocator from UT3, is it still legal for me to release my UDK game as a free non-commercial download or does that still violate the EULA?

A: UTGame script code is not consider part of the restricted asset set. You may freely use it in your UDK application as you see fit.

Q: Are you allowed to release a free UDK game based on intellectual property you don't own or have rights to? For example lots of people make mods based on Star Wars with no problems, but would releasing one through the UDK be allowed?

A: We strongly advise against anyone violating another's intellectual property rights with their UDK application. If you have any questions about this issue we also strongly advise you seek the advice of a qualified intellectual property attorney.

Q: Can we begin making professional quality video training for the Unreal Development Kit, and sell the videos, for profit - using only the free version of the UDK?

A:

1. You may create “unofficial” UDK documentation provided the following: a Your content is new and original. b You do not republish content from licensed sources, e.g. the Mastering Unreal Technology books from Sams and 3D Buzz. c You do not republish content available at Epic Games’ web sites, including UDN. d You give appropriate legal attribution to Epic Games’ trademarks* and clearly cite your work as "not endorsed by Epic Games." e You abide by the UDK end-user license agreement (EULA).
2. You may give away or sell unofficial documentation without a license from Epic.
3. Epic does not charge a royalty fee for unofficial documentation.

Unreal Development Kit (UDK) © 2009, Epic Games, Inc. Epic, Epic Games, Gears of War, Gears of War 2, Unreal, AnimSet Viewer, AnimTree Editor, Unreal Cascade, Unreal Content Browser, Unreal Development Kit, Unreal Editor, Unreal Engine, Unreal Kismet, Unreal Lightmass, Unreal Matinee, Unreal PhAT, UnrealScript and Unreal Tournament are trademarks or registered trademarks of Epic Games, Inc. in the United States of America and elsewhere. All other trademarks are the property of their respective owners.

Q: Can I release a noncommercial game that uses the “Unreal Tournament 3” assets included with UDK?

A: Yes. You can use UT3 assets included with UDK for a noncommercial game, but not UT3 assets not included with UDK.

Q: Can I release a commercial game that uses the “Unreal Tournament 3” assets included with UDK?

A: Yes, with one exception. You may not release anything marked as a SkeletalMesh in the Content Browser in a commercial UDK application.

Q: I’ve developed a UDK game I wish to sell via Xbox LIVE®, PLAYSTATION® NETWORK and/or on the PC. What's the next step?

A: Commercial release on the PC is already covered and we've got great terms at www.udk.com/licensing for those who want to sell games created with UDK for PC. The UDK does not currently support the Xbox 360 or the PS3.

Console is a little more complicated because you need to be licensed by the console manufacturers before you can get a development kit, which involves a concept submission and (hint, hint!) UDK would be great for proving your worth in the concept submission stage.

If you can get through that step we're more than happy to talk with you about making a full source code license available under great business terms.

Q: Can we change the static UDK splash screen in our UDK apps?

A: Yes, you may alter the static splash screen as you see fit. The UDK movie, on the other hand, must not be changed.

Q: Can I sell works created using UDK?

A: The short answer is “Yes.” However you need a commercial license. Please view the information at our licensing page.

Q: May I create and/or sell documentation or publications based on UDK?

A: You may create “unofficial” UDK documentation provided the following:

• Your content is new and original.
• You do not republish content from licensed sources, e.g., the Mastering Unreal Technology books from Sams and 3D Buzz.
• You give appropriate legal attribution to Epic Games’ trademarks* and clearly cite your work as "not endorsed by Epic Games."
• You abide by the UDK end-user license agreement (EULA).

You may give away or sell unofficial documentation without a license from Epic. Epic does not charge a royalty fee for unofficial documentation.

* "Unreal Development Kit (UDK) © 2009, Epic Games, Inc. Epic, Epic Games, Gears of War, Gears of War 2, Unreal, AnimSet Viewer, AnimTree Editor, Unreal Cascade, Unreal Content Browser, Unreal Development Kit, Unreal Editor, Unreal Engine, Unreal Kismet, Unreal Lightmass, Unreal Matinee, Unreal PhAT, UnrealScript and Unreal Tournament are trademarks or registered trademarks of Epic Games, Inc. in the United States of America and elsewhere. All other trademarks are the property of their respective owners"

Q: Do I need a commercial license to enter my UDK application in a development contest?

A:You may participate in development contests like the Make Something Unreal Contest or Independent Games Festival without a commercial license provided any winnings remain under $100,000.00. If your winnings exceed $100,000.00 (AWESOME!) you will need a commercial license and are required to pay a royalty.

Q: Can I take advantage of Steamworks as integrated into the UDK in a commercial application?

A: No, you must get a Steamworks license from Valve before using Steamworks in a commercial UDK application. Contact Valve for more information at: steamworks@valvesoftware.com

Support and Community

Q: Who can I contact if I have a question?

A: Your best bet is to visit the UDK forums.

Content Creation

Q: What are the working units of the Unreal Editor?

A: For the working units of the Unreal Editor, as well as common scales, see the following UDN document Unreal Units.

Errors

Q: What does it mean when UDK crashes at start and the log says: BulkDataOffsetInFile and something about Tex2D, a specific texture is declared?

A: Your UDK application might be missing a texture that is referenced in some other asset that is being loaded. Check the log file.

Do you have any other questions?

If you have another other questions that aren't answered here, try searching the documentation, or the UDK forums. Someone else may have already run into the same problems. If you still can't find the answers you're looking for don't hesitate to post your question there.