Asset Licensing and Attribution

Intermediate40-60 minutesCross-platformSteam Workshop

Every asset used in an Unturned™ mod — a texture, a 3D mesh, a sound file, a font, an icon — was created by someone. That person or organization holds copyright over the asset from the moment they fixed it in a tangible medium. When a modder incorporates a third-party asset into a mod, they are exercising one or more exclusive rights that belong to the copyright holder: the right to reproduce the work, to create derivative works from it, and to distribute it publicly. Those rights may only be exercised legally if the copyright holder has granted permission — through a license agreement — or if a recognized legal exception applies.

This article is the 57 Studios™ reference for asset licensing and attribution. It covers the licensing frameworks that appear most often in the Unturned modding ecosystem, explains why attribution matters legally and practically, and establishes the attribution conventions that all 57 Studios mods follow. Modders who have questions about whether a specific third-party asset use constitutes a derivative work should also review Derivative Works and Reskins. Modders who have received a takedown notice regarding their mod should review How the Steam DMCA Process Works.

Why this matters specifically for Unturned mods

Unturned™ mods are distributed publicly — primarily through the Steam Workshop — and are downloaded and used by a large community. This is not the same as keeping a personal remix of an asset on a local machine. The moment a modder uploads a mod to the Workshop, they are distributing copies of every asset in that mod to every person who subscribes. Distribution is one of the exclusive rights of a copyright holder, which means that uploading a mod containing an unlicensed third-party asset is an act of copyright infringement as a matter of US copyright law, regardless of whether the modder made money from it.

Distribution triggers infringement

Under US copyright law (17 U.S.C. § 106), the exclusive right to distribute copies belongs to the copyright holder. Uploading a mod to the Steam Workshop is distribution. An asset without a license that permits public distribution may not legally be included in a Workshop upload, even if the asset is freely downloadable elsewhere on the internet.

The practical consequence is that a modder who uses an unlicensed asset exposes themselves to a DMCA takedown of their mod, and potentially of their Steam account's Workshop content in aggregate. Smartly Dressed Games, as the platform operator for Unturned's Workshop presence on Steam, is obligated to respond to valid DMCA takedown notices by removing infringing content. Prevention is significantly less costly than response.

57 Studios policy

57 Studios requires all published mods to document the license status of every third-party asset used. Assets with no identifiable license are treated as "all rights reserved" and are excluded from mods unless explicit written permission is obtained from the copyright holder. This policy is enforced at the mod review stage before publication.

Understanding the scope of copyright in a mod

A finished Unturned™ mod is not a single copyrightable work — it is a collection of independently copyrightable elements. Each element has its own copyright status, its own rights holder, and its own license (or lack of one). The following table maps common mod components to their copyright implications.

Mod component	Copyright status	Typical license sources
3D mesh authored by the modder from scratch	Original work; modder holds copyright	N/A — modder is the rights holder
3D mesh purchased from an asset marketplace	Proprietary; rights holder is the seller or original artist	Marketplace terms of service
3D mesh from a CC-licensed asset pack	CC license applies; rights holder is original artist	License file bundled with pack
Texture painted from scratch in Substance Painter	Original work; modder holds copyright	N/A — modder is the rights holder
Texture downloaded from a free texture library	License varies by library; confirm per download	Library's per-asset license page
PBR normal map generated from a photo	Composite; photo may carry its own copyright	Depends on photo license
Sound effect from a sound library	Proprietary or CC; depends on library	Library's subscription terms or per-asset license
Sound effect recorded by the modder	Original work; modder holds copyright	N/A — modder is the rights holder
Font used in UI elements	Proprietary or OFL; font copyright is separate from typeface	Font file's license file
Icon from an open-source icon set	Typically MIT or CC	Icon set's README or license file
Script adapted from a community tutorial	Depends on the tutorial's stated license or implied permission	Contact tutorial author if unclear

Every row in the above table with a non-N/A "Typical license sources" entry represents a potential attribution and compliance obligation. A mod that uses twenty third-party assets has twenty independent copyright relationships to manage.

Asset tracking from the start

The point at which attribution is easiest to document is the moment the asset is sourced — not after the mod is finished. 57 Studios recommends maintaining a running asset log during mod development, with one row per third-party asset, including the source URL, author, and license identifier. This log becomes the basis for the Workshop description's Asset Credits section.

What the 57 Studios asset log looks like

During development, modders working under the 57 Studios umbrella maintain an asset log in a plaintext file alongside the project folder. The minimum columns are:

Column	Content
Asset name	Short descriptive name for internal reference
File(s)	The filename(s) of the asset in the project
Author	Original creator's name or username
Source URL	Direct URL to the asset or asset pack
License	Short identifier (e.g., CC-BY 4.0, MIT)
Modification	Brief description of changes made
Attribution written?	Yes / No — whether the Workshop description has been updated

The asset log is reviewed at the pre-publication checklist stage. Mods with incomplete asset logs are not submitted to the Workshop until the log is complete and the Workshop description draft has been reviewed.

Core licensing concepts

Before working through specific licenses, a set of foundational concepts applies across all license frameworks.

What a license is

A license is a legal instrument through which a copyright holder grants permission to others to exercise some or all of the exclusive rights that would otherwise belong only to the holder. A license may be:

• Exclusive or non-exclusive. An exclusive license grants the permission to only one party. A non-exclusive license grants the same permission to multiple parties simultaneously.
• Royalty-bearing or royalty-free. A royalty-bearing license requires payment per use. A royalty-free license permits use without per-use payment (though an upfront fee may apply).
• Revocable or irrevocable. Revocable licenses can be withdrawn by the licensor. Irrevocable licenses cannot be withdrawn once granted, provided the licensee complies with the license terms.
• Conditional or unconditional. Conditional licenses require the licensee to satisfy specific conditions (such as providing attribution) in order to retain the license. Unconditional licenses impose no conditions.

In the open-source and Creative Commons ecosystems — the two ecosystems most commonly encountered in modding — licenses are non-exclusive, royalty-free, irrevocable (provided conditions are met), and conditional.

What "open source" means for assets

"Open source" as a term originated in software licensing. Applied to assets (textures, meshes, sounds), the analogous concept is "open content" — assets whose license permits modification, redistribution, and in many cases commercial use, subject to stated conditions. The Creative Commons license suite is the most widely used open-content license family for non-software creative works, including the kinds of assets that appear in Unturned mods.

What "public domain" means

A work enters the public domain when its copyright expires (typically 70 years after the author's death in the US) or when the copyright holder explicitly dedicates the work to the public domain. Public domain works have no copyright restrictions — they may be used, modified, and distributed without permission or attribution. However, a work being freely available on the internet does not mean it is in the public domain. Availability and public domain status are distinct.

"Free to use" does not mean "public domain"

Assets labeled "free" or "free to download" on an asset website may still be under copyright. "Free" in commerce typically means "no charge" — it does not mean "no copyright restrictions." Always confirm the specific license, not just the price.

License frameworks in the modding ecosystem

Creative Commons licenses

The Creative Commons (CC) suite is a family of standardized public licenses for creative works. Each license is identified by a short-form name composed of the CC prefix and a combination of condition codes. The following are the CC licenses most commonly encountered in the Unturned modding ecosystem.

CC0 (Public Domain Dedication)

CC0 is not strictly a license — it is a public domain dedication. The creator waives all copyright and related rights to the fullest extent permitted by law. CC0 assets may be used, modified, distributed, and built upon for any purpose, including commercial use, without attribution and without conditions. CC0 is the most permissive CC instrument.

CC0 in practice

CC0 assets are preferred for mod assets when available, precisely because they impose no conditions. A mod using only CC0 and original assets has no attribution obligations and no license compatibility concerns. However, providing voluntary credit for CC0 work is considered good community practice, even though it is not required.

CC-BY (Attribution)

CC-BY permits use, modification, and distribution for any purpose, including commercial, provided that the original author receives attribution in the form specified by the license (or, if no form is specified, in a reasonable manner). Attribution must include the author's name, the title of the work (if supplied), the URI or hyperlink to the work (if applicable), and the license identifier.

Attribution is a condition of the license. A modder who uses a CC-BY asset without providing attribution has not satisfied the license condition and is therefore not operating within the license grant — the use becomes unauthorized.

CC-BY-SA (Attribution-ShareAlike)

CC-BY-SA adds a ShareAlike condition to CC-BY. ShareAlike means that derivative works — works that incorporate or build upon the CC-BY-SA asset — must be distributed under the same CC-BY-SA license (or a compatible license, per Creative Commons compatibility rules). This is the "viral" clause: the license propagates to the derivative.

ShareAlike and mod distribution

A mod that incorporates a CC-BY-SA texture and distributes the mod must license the combined work under CC-BY-SA. This means anyone who downloads the mod has the rights to use, modify, and redistribute the mod's contents under CC-BY-SA terms. If the modder intends to retain proprietary control over their mod's assets, CC-BY-SA source assets are incompatible with that goal.

CC-BY-NC (Attribution-NonCommercial)

CC-BY-NC permits use, modification, and distribution for non-commercial purposes, with attribution. Commercial use is not permitted without additional permission from the copyright holder.

Whether a Unturned mod using CC-BY-NC assets constitutes "commercial use" depends on whether the modder is generating revenue from the mod. A free Workshop upload with no associated monetization is non-commercial. A mod sold through Tebex or another storefront, or bundled with a paid server subscription, is commercial. Modders who intend to monetize their work must not use CC-BY-NC assets without separate commercial permission.

CC-BY-ND (Attribution-NoDerivatives)

CC-BY-ND permits use and distribution of the unmodified work, with attribution, including commercial use. It prohibits creating derivative works — works that modify or adapt the original. In modding, this typically means CC-BY-ND assets may be included in a mod unchanged, but may not be modified (retextured, reshaped, repurposed into a different item).

Refer to Derivative Works and Reskins for the framework used to determine whether a particular modification of an asset constitutes a derivative work under copyright law.

CC-BY-NC-SA (Attribution-NonCommercial-ShareAlike)

CC-BY-NC-SA combines the NonCommercial and ShareAlike conditions with Attribution. It is among the most restrictive CC licenses: non-commercial only, attribution required, derivatives must use CC-BY-NC-SA. This license is common for community-made assets that the creator wants to keep in the community ecosystem without enabling commercial extraction.

License compatibility matrix

Not all licenses are mutually compatible. A mod that combines assets under different licenses must satisfy all applicable license conditions simultaneously. The following matrix shows compatibility between the license families most commonly encountered in Unturned modding.

Source asset license	Can use in free Workshop mod?	Can use in commercial mod?	Can modify?	Mod must use same license?	Attribution required?
CC0	Yes	Yes	Yes	No	No (voluntary)
CC-BY	Yes	Yes	Yes	No	Yes
CC-BY-SA	Yes	Yes	Yes	Yes (CC-BY-SA)	Yes
CC-BY-NC	Yes	No	Yes	No	Yes
CC-BY-NC-SA	Yes	No	Yes	Yes (CC-BY-NC-SA)	Yes
CC-BY-ND	Yes (unmodified only)	Yes (unmodified only)	No	No	Yes
MIT	Yes	Yes	Yes	License text must be included	Yes (credit in license text)
ISC	Yes	Yes	Yes	License text must be included	Yes (credit in license text)
Proprietary / ARR	Only with explicit permission	Only with explicit permission	Only with explicit permission	Per permission terms	Per permission terms

How to use this table

Locate the source asset's license in the leftmost column. Read across the row to determine the conditions that apply to your mod. If any cell in the row is "No" or "Only with explicit permission" and your use case falls into that category, you cannot legally include the asset in your mod without additional permission.

MIT and ISC licenses

MIT and ISC are software-originating licenses frequently applied to open-source tooling, scripts, and occasionally to asset packs released by developers who prefer the software license tradition. Both are permissive: use, modification, distribution, and commercial use are all permitted, provided the original license text and copyright notice are included in the distribution. For a Unturned mod, this means including the license text in the mod's Workshop description or in a bundled LICENSE.txt file.

Proprietary and "all rights reserved"

When a work carries no license, or explicitly states "all rights reserved," the copyright holder has granted no permissions. The work may not be reproduced, modified, or distributed without explicit permission from the holder. This is the default copyright state for any work that does not carry a permissive license.

No license = all rights reserved

Silence is not permission. An asset with no license statement is under full copyright. Using it without permission is infringement, regardless of how it was obtained or how it is used. When in doubt, contact the creator and request permission in writing.

Why attribution is required, not optional

Modders sometimes treat attribution as a courtesy rather than a legal requirement. For CC-BY, CC-BY-SA, CC-BY-NC, CC-BY-NC-SA, and CC-BY-ND licenses, attribution is a condition of the license grant — not an optional courtesy. Failing to attribute terminates the license. A modder who fails to attribute a CC-BY asset has lost the legal right to use it, even though the attribution requirement is the only condition of the CC-BY license.

For MIT and ISC licensed assets, the license text contains the copyright notice and attribution requirement. Distributing a mod that includes MIT-licensed assets without the license text is a violation of the MIT license terms.

Attribution is a condition, not a suggestion

Under Creative Commons licenses, the attribution requirement is a legal condition. Failure to comply terminates the license grant. A failed attribution converts an authorized use into an unauthorized one.

How to credit sources in a Workshop description

The Steam Workshop description is the primary location for third-party asset attribution in Unturned mods. A standard Workshop description should include an "Asset Credits" or "Third-Party Assets" section listing every third-party asset, its author, and its license.

Minimum required attribution elements

Per Creative Commons guidelines, attribution for a CC-BY or CC-BY-SA asset must include:

1. The name of the author or creator.
2. The title of the work (if the work has a title).
3. A URI or URL to the original work, if applicable and available.
4. The license identifier (e.g., CC-BY 4.0).
5. An indication of whether the asset was modified (e.g., "texture recolored from original").

For MIT assets, attribution must include:

1. The name of the original author.
2. The year of the copyright notice (as it appears in the license).
3. A statement that the MIT license applies.
4. The full license text, either embedded in the description or in a bundled LICENSE.txt.

Attribution placement

Location	Suitability	Notes
Steam Workshop description (Credits section)	Primary — required for all mods	Most visible to end users and to rights holders who may review the mod.
Bundled README.txt or LICENSE.txt	Supplementary — required for MIT/ISC	Packaged with the mod files, visible to modders who unpack the mod.
In-game loading screen or mod information panel	Optional — high visibility	Appropriate for large mods with significant third-party asset use.
GitHub repository README (if source is public)	Supplementary	Useful for open-source mods where the source is publicly hosted.

Attribution in the Workshop description

The Workshop description's Credits section should be formatted for human readability. Use a consistent format: one asset per entry, with the asset name, author, license, and URL on a single line or in a short block. Inconsistent or missing attribution in Workshop descriptions is the most common attribution compliance failure in the Unturned modding community.

The 57 Studios attribution convention

57 Studios has adopted a standardized attribution block format for all mods that include third-party assets. This format satisfies the minimum requirements of CC-BY, CC-BY-SA, CC-BY-NC, CC-BY-NC-SA, CC-BY-ND, MIT, and ISC licenses. Using the standard format for CC0 assets is optional but encouraged.

Sample attribution block (CC-BY asset)

Tactical Rail Texture
  Author: [Author Name]
  Source: [Original URL or "Asset Pack Name, [Asset Store Platform]"]
  License: Creative Commons Attribution 4.0 International (CC-BY 4.0)
  Modification: Recolored from tan to dark grey; brightness adjusted.

Sample attribution block (CC-BY-SA asset)

Corrugated Metal Normal Map
  Author: [Author Name]
  Source: [Original URL or asset pack name]
  License: Creative Commons Attribution-ShareAlike 4.0 International (CC-BY-SA 4.0)
  Modification: None. Used as-is.
  Note: This mod's distribution is subject to CC-BY-SA 4.0 terms for this asset.

Sample attribution block (MIT asset)

Open-Source Icon Set (scope_icon.png, grip_icon.png)
  Author: [Author Name], Copyright (c) [Year]
  Source: [Repository URL or "Distributed with [Tool Name]"]
  License: MIT License
  License Text: Included in /LICENSE.txt bundled with this mod.
  Modification: Exported at 256x256 from the original SVG source.

Sample attribution block (CC0 asset)

Concrete Base Texture
  Author: [Author Name]
  Source: [Original URL]
  License: Creative Commons Zero (CC0 1.0 Universal) — No conditions.
  Modification: Scaled to 2048x2048, color graded for Unturned's lighting environment.

Sample attribution block (explicit permission, proprietary)

[Weapon Name] Reference Mesh
  Author: [Author Name]
  Source: Private commission, used with written permission dated [Date].
  License: Proprietary — permission granted for use in [Mod Name] only.
  Modification: Rig added; textures authored by 57 Studios.

57 Studios internal requirement

Every 57 Studios mod that includes a third-party asset must contain an "Asset Credits" section in its Workshop description using the above format. Mods submitted for internal review without this section are returned to the modder for completion before they are approved for publication.

License selection: which license should you apply to your own work?

When a modder releases their own original assets — textures, meshes, sounds, scripts — they become a licensor. Choosing the right license for original assets affects how the community can use and build on those assets.

Goal	Recommended license
Maximum community adoption; no conditions on use	CC0
Attribution credit, but maximum flexibility for others	CC-BY 4.0
Attribution and keep derivatives open (copyleft)	CC-BY-SA 4.0
Attribution but restrict to non-commercial use	CC-BY-NC 4.0
Attribution, non-commercial, keep derivatives open	CC-BY-NC-SA 4.0
Allow use of originals only; no modifications	CC-BY-ND 4.0
Full proprietary control; no sharing without permission	No license (all rights reserved)

Choosing a license for community growth

57 Studios recommends CC-BY 4.0 as the default license for original assets that modders want to share broadly. It provides attribution credit while imposing the minimum conditions necessary to make the asset usable in a wide range of downstream projects.

Risks of using uncredited or unlicensed assets

The consequences of including unlicensed or uncredited assets in a published mod are not theoretical. They arise regularly in the Unturned Workshop community.

Risk	Description
DMCA takedown	The rights holder files a DMCA notice with Steam. The mod is removed. Repeated notices can lead to account suspension.
Workshop ban	Steam's policies permit Workshop bans for repeat infringers. This affects all Workshop activity, not just the infringing mod.
Community reputation damage	Rights holders who discover unlicensed use in the modding community often post publicly. Reputation damage can precede formal action.
License termination	Failure to comply with a CC license condition (such as attribution) terminates the license retroactively. The use becomes infringing from the moment the condition was first violated.
Loss of commercial revenue	If the infringing mod generates revenue (Tebex sales, server subscription bonuses), that revenue may be subject to disgorgement in a legal claim.
Platform escalation	If Steam's DMCA process results in account action, other Steam services (game library, developer account) may also be affected.

License termination is retroactive

Under the Creative Commons license framework, failure to comply with a license condition does not merely breach the license going forward — it terminates the license as of the date the condition was violated. This means the use was unlicensed from that point. The modder cannot cure a past infringement simply by adding attribution after the fact; they must seek a new license grant from the rights holder.

Handling license version differences

Creative Commons licenses have been released in several versions (1.0, 2.0, 2.5, 3.0, 4.0). Each version is a distinct legal document. The license version specified on the asset is the version that governs that asset — a modder may not apply the terms of CC-BY 4.0 to an asset that was released under CC-BY 2.0.

In practice, the substantive rights granted by CC-BY 2.0 through CC-BY 4.0 are similar for most modding use cases. The primary differences between versions are:

Difference	CC-BY 2.0 / 2.5 / 3.0	CC-BY 4.0
Database rights (EU)	Not explicitly addressed	Explicitly covered
Moral rights	Not explicitly addressed	Explicitly addressed (waived to extent possible)
Patent rights	Not addressed	Addressed (limited patent grant)
Attribution format	More prescriptive	More flexible
License porting	Ported national versions exist	International only; no national ports

For the purposes of Unturned modding attribution, the primary concern is attribution format. When citing an older CC version, the attribution should still match the format the original asset specified, or use the minimum elements listed in the Creative Commons attribution guidelines for that version.

When the asset says "CC-BY" without a version

Some assets specify "Creative Commons Attribution" without a version number. In this case, contact the creator to confirm the intended version. If the creator is unreachable and the asset has been distributed this way for an extended period, treat it as CC-BY 4.0 in the attribution block and note the ambiguity in the mod's asset log.

Asset sources commonly used in the Unturned modding ecosystem

Modders source third-party assets from a range of locations. The following table describes the most common source categories and their typical license profiles. These are generalizations — always confirm the license of the specific asset being used.

Source type	Examples	Typical license profile	Key verification step
Open-source 3D model repositories	PolyHaven, Sketchfab (filtered by CC)	CC0, CC-BY, CC-BY-SA	Check the per-model license page; licenses vary by model even within the same platform
Free texture libraries	PolyHaven, AmbientCG	CC0	Confirm CC0 on the asset page; these libraries are generally CC0 but confirm per download
Paid asset marketplaces	Unity Asset Store, CGTrader	Proprietary (marketplace license)	Read the marketplace's standard license and the per-asset extended license if applicable
Modding community asset shares	Discord servers, community forums	Varies widely; often unstated	Contact the poster; treat unstated licenses as ARR
Government-produced reference photos	US military image archives	Often public domain (US federal works)	Confirm country of origin; public domain applies to US federal works specifically
Sound libraries	Freesound, ZapSplat	CC0, CC-BY, proprietary	Check per-sound license; Freesound in particular has per-sound licenses that vary widely
Icon sets	Feather, Lucide, Tabler	MIT	Confirm MIT license in the icon set's repository README

Community forum "free to use" assets

Assets shared in Discord servers and modding forums with the statement "free to use" carry significant ambiguity. The person sharing the asset may not be the rights holder, or may not understand the distinction between "free to download" and "licensed for redistribution." Treat community-shared assets with no explicit license as requiring direct confirmation from the original creator before use in a Workshop-published mod.

Practical workflow: before publishing a mod

The following checklist should be completed for every mod before Workshop submission. It is incorporated into the 57 Studios pre-publication review process.

Commercial mods and licensing: additional considerations

The Unturned modding community includes both free and commercial content. Mods distributed for free through the Steam Workshop, mods sold through Tebex stores, and mods that unlock premium server features all carry different commercial implications for asset licensing.

Defining "commercial use"

Creative Commons defines commercial use as use "primarily intended for or directed toward commercial advantage or monetary compensation." In the context of Unturned mods, the following scenarios are generally considered commercial:

Scenario	Commercial classification	Asset license implication
Free Workshop mod with no associated revenue	Non-commercial	CC-BY-NC assets permitted
Mod bundled with a paid Tebex item	Commercial	CC-BY-NC assets NOT permitted
Mod that unlocks content for server premium subscribers	Commercial	CC-BY-NC assets NOT permitted
Mod used internally for a paid server's game mode	Depends on revenue structure	Confirm with rights holder if using CC-BY-NC assets
Mod released free with a "tip jar" link	Arguably commercial	Treat as commercial for safety; avoid CC-BY-NC assets

Revenue adjacency

Even if the mod itself is free, if it provides meaningful commercial benefit to a revenue-generating activity (e.g., attracting players to a paid server), a conservative interpretation of "commercial use" may apply. 57 Studios recommends treating any mod connected to a revenue stream as commercial for asset licensing purposes.

Tebex storefront and asset licensing

Mods sold through Tebex are unambiguously commercial. This means:

1. CC-BY-NC assets may not be included in Tebex-sold mods without additional written commercial permission from the rights holder.
2. CC-BY and CC0 assets may be used in commercial mods.
3. Proprietary assets require the specific written permission to cover commercial distribution.
4. MIT-licensed assets may be used commercially, provided the license text is included.

57 Studios maintains a separate review step for commercial mods specifically to confirm that all assets clear the commercial use requirement.

Splitting commercial and non-commercial asset pools

When a modder maintains both free Workshop releases and commercial Tebex products, 57 Studios recommends maintaining two separate asset pools:

• Community pool — assets cleared for non-commercial use (CC0, CC-BY, CC-BY-SA, MIT, and NC-cleared assets with explicit permission). These assets may be used in any free Workshop mod without restriction.
• Commercial pool — assets cleared for commercial use (CC0, CC-BY, CC-BY-SA, MIT, proprietary with explicit commercial permission). These assets are the only ones permitted in Tebex-sold or server-premium-bundled mods.

Maintaining these two pools as documented lists in the 57 Studios asset log system ensures that the correct assets are pulled for each project type, and that commercial mods are never assembled from assets that include NC-restricted material.

Retroactive commercialization

A mod that begins as a free Workshop release and is later commercialized (moved to Tebex, bundled with paid server access) creates a licensing issue for any CC-BY-NC assets it contains. The assets that were permissible for non-commercial distribution are no longer permissible once the distribution becomes commercial. Before commercializing a mod:

1. Audit all third-party assets for CC-BY-NC or CC-BY-NC-SA licenses.
2. Replace NC-restricted assets with CC-BY, CC0, or MIT alternatives, OR
3. Obtain written commercial permission from each NC-restricted asset's rights holder.

This audit should happen before the mod is listed commercially, not after.

When to seek written permission

For assets that are not under a permissive open-content license, written permission from the rights holder is the only mechanism that authorizes use. Written permission is the appropriate path when:

• The asset is under a proprietary license and no adequate open-content alternative exists.
• The asset is CC-BY-NC and the mod will be commercial.
• The asset is CC-BY-ND and the mod will modify the asset.
• The asset has no stated license and the rights holder can be contacted.
• The license is ambiguous and clarification is needed before use.

What a written permission request should include

When contacting a rights holder for permission, the request should be specific and complete. The following elements should be included:

1. Identification of the specific asset — title, filename, URL, and a brief description.
2. Description of the intended use — what the mod is, where it will be distributed (Steam Workshop, Tebex), whether it is commercial or free.
3. The specific rights being requested — reproduction, distribution, modification, commercial use.
4. The anticipated duration — for an ongoing mod, permission should be requested indefinitely, or for as long as the mod is distributed.
5. Attribution commitment — a statement that attribution will be provided in the form the rights holder specifies.

A clear, specific request makes it easier for the rights holder to evaluate and grant permission. Vague requests ("can I use your stuff?") are more likely to receive a non-response or a denial.

Written permission = email or documented message

Written permission does not require a formal legal document. An email, a Discord message, or a forum post from the verified rights holder — one that clearly grants the requested rights — is sufficient for documentation purposes. Save the permission documentation in the project's asset log with a timestamp.

Appendix A: Common license identifiers and their short-form codes

When searching for asset licenses, the following identifiers appear across the asset repositories most commonly used by Unturned modders.

Short-form identifier	Full license name	Version(s) in common use
CC0	Creative Commons Zero (Public Domain Dedication)	1.0 Universal
CC-BY	Creative Commons Attribution	2.0, 2.5, 3.0, 4.0
CC-BY-SA	Creative Commons Attribution-ShareAlike	2.0, 2.5, 3.0, 4.0
CC-BY-NC	Creative Commons Attribution-NonCommercial	2.0, 2.5, 3.0, 4.0
CC-BY-NC-SA	Creative Commons Attribution-NonCommercial-ShareAlike	2.0, 2.5, 3.0, 4.0
CC-BY-ND	Creative Commons Attribution-NoDerivatives	2.0, 2.5, 3.0, 4.0
CC-BY-NC-ND	Creative Commons Attribution-NonCommercial-NoDerivatives	2.0, 2.5, 3.0, 4.0
MIT	MIT License	(No version system; single canonical text)
ISC	ISC License	(No version system; single canonical text)
Apache-2.0	Apache License 2.0	2.0
GPL-2.0	GNU General Public License	2.0 (rarely used for assets; common for software)
ARR	All Rights Reserved	(Not a formal license; indicates no permissions granted)

Version currency

Use the most recent version of a Creative Commons license available on the asset (typically 4.0) when citing. If an older version is specified on the asset itself, cite the version that applies to that specific asset — do not upgrade the version citation.

Appendix B: Attribution block template for the 57 Studios Workshop description

Copy and fill in the following template for each third-party asset in a mod's Workshop description. Delete lines that do not apply (e.g., the Note line for non-ShareAlike assets).

--- ASSET CREDITS ---

[Asset Name or Description]
  Author: [Full name or username of original creator]
  Source: [URL of original asset or name of asset pack and platform]
  License: [Full license name and version, e.g., "Creative Commons Attribution 4.0 International (CC-BY 4.0)"]
  Modification: [Describe modifications, or "None. Used as-is."]
  Note: [Any special conditions, e.g., "This mod's redistributable content is subject to CC-BY-SA 4.0 for this asset." — delete if not applicable]

[Asset Name or Description]
  Author: ...
  ...

--- END ASSET CREDITS ---

Appendix C: License compatibility for mixed-license mods

When a mod includes assets under multiple different licenses, the mod's overall distribution must satisfy all applicable license conditions simultaneously. This can create incompatibilities.

License combination	Compatible?	Condition to resolve
CC0 + CC-BY	Yes	Attribute CC-BY assets. CC0 has no conditions.
CC-BY + CC-BY-SA	Yes, with condition	Mod must be distributed under CC-BY-SA or compatible.
CC-BY-SA + CC-BY-NC-SA	Requires verification	Both require ShareAlike. Confirm the SA licenses are compatible per Creative Commons compatibility rules.
CC-BY-SA + CC-BY-ND	No	CC-BY-SA requires derivatives to use CC-BY-SA. CC-BY-ND prohibits derivatives. These conditions cannot both be satisfied for a mod that modifies either asset.
CC-BY-NC + CC-BY (commercial mod)	No	CC-BY-NC restricts commercial use. CC-BY allows it. Using both in a commercial mod violates the CC-BY-NC terms for the NC asset.
MIT + CC-BY-SA	Yes, with condition	Include MIT license text. Mod is subject to CC-BY-SA for the SA asset.
Proprietary (with permission) + CC-BY	Yes	Attribute CC-BY asset. Proprietary asset use governed by the specific permission granted.

Incompatible licenses require asset replacement

When two assets in a mod carry mutually incompatible licenses, there is no legal mechanism to reconcile them in the same distribution. One of the assets must be replaced with an asset under a compatible license, or separate written permission must be obtained from one rights holder to permit use under the other license's terms.

Frequently asked questions

Do I need to attribute CC0 assets?

Attribution is not legally required for CC0 assets because the creator has waived all rights. However, voluntary attribution is considered good community practice. 57 Studios encourages crediting CC0 asset creators even when not legally required, and includes them in the Workshop description's Asset Credits section.

What if I cannot identify the original author of an asset?

If the original author of a third-party asset cannot be identified, the asset should be treated as "all rights reserved" and excluded from the mod. Using an asset when the author is unknown provides no legal protection; the rights holder may surface at any time and assert their rights.

Does using an asset "for free" mean it has no copyright?

No. Copyright exists independently of whether the asset costs money. Assets distributed at no charge are still protected by copyright unless the rights holder has expressly waived copyright (as with CC0) or granted a license that permits the uses in question.

If I modify a CC-BY asset significantly, do I still need to attribute?

Yes. Attribution is required for CC-BY assets regardless of the degree of modification. The condition is tied to the use of the asset, not to whether the modification is substantial or minor. Additionally, if the modification rises to the level of a derivative work, additional conditions may apply depending on the specific CC license variant. See Derivative Works and Reskins for the derivative work analysis framework.

What happens if a rights holder reaches out after the mod is already published?

Contact the rights holder promptly. In most cases, they will want one of three outcomes: attribution added to the Workshop description, removal of their asset from the mod, or a licensing agreement (which may involve payment for commercial use). Responding promptly and professionally typically leads to a resolution short of a formal DMCA notice. 57 Studios should be notified of any such contact so that the response is coordinated.

Can I use vanilla Unturned textures or meshes in my mod?

Vanilla Unturned™ assets — textures, meshes, sounds, and other content created by Smartly Dressed Games — are proprietary assets owned by Smartly Dressed Games. Their use in community mods is governed by Smartly Dressed Games' modding policy, not by any Creative Commons or open-source license. Refer to the official Unturned modding documentation at https://docs.smartlydressedgames.com/en/stable/ for the current terms governing use of vanilla content in community mods. See also Smartly Dressed Games Modding Policy.

What license does 57 Studios use for its own mod assets?

Original assets created by 57 Studios for its mods are released under the license specified in each mod's Workshop description. 57 Studios' default for community-intended assets is CC-BY 4.0. Proprietary assets created for internal use or for commercial mods are "all rights reserved" unless the specific mod's description states otherwise.

Is a license for the mod the same as a license for its assets?

No. A mod's overall Workshop description may state a license for the mod as a whole, but third-party assets within the mod remain under their original licenses regardless of what the mod's description states. A modder cannot override a CC-BY-SA asset's ShareAlike condition by declaring their mod to be "all rights reserved." The asset's original license governs the asset.

Does the Steam Subscriber Agreement affect licensing of mod assets?

The Steam Subscriber Agreement and Steam Workshop terms govern the relationship between the modder and Valve regarding Workshop uploads. They do not supersede copyright law or the terms of any license between the modder and a third-party asset creator. The Steam terms create an additional layer of obligations on top of copyright law — they do not replace it.

What is a "copyright notice" and where should it appear?

A copyright notice is a statement that identifies the copyright holder and, typically, the year of first publication. In the form "Copyright (c) [Year] [Author Name]" or "© [Year] [Author Name]." For MIT-licensed assets, the copyright notice is embedded in the license text. For Creative Commons assets, the author's name and the license identifier serve the same function. Copyright notices for third-party assets should appear in the mod's Asset Credits section or in a bundled LICENSE.txt.

Do I need a lawyer to handle asset licensing for a mod?

Licensing documentation for a mod is not legal advice — it is compliance documentation. Modders who follow the framework in this article are equipped to handle the asset licensing requirements for a standard Workshop mod. However, modders who are building commercial products, entering into licensing agreements with third parties, or dealing with contested DMCA claims should consult a licensed attorney. 57 Studios does not provide legal advice.

What should I do if an asset's license conflicts with the Steam Subscriber Agreement?

The Steam Subscriber Agreement grants Valve a broad license to the content uploaded to the Workshop by users. If a third-party asset's license includes a "no sublicense" restriction, uploading that asset as part of a Steam Workshop item may technically conflict with the Subscriber Agreement's sublicensing provisions. This is an area of legal complexity that has not been definitively resolved in the context of Unturned modding. As a practical matter, 57 Studios recommends using CC0, CC-BY, and MIT assets to minimize this risk, and consulting the rights holder if a "no sublicense" restriction applies to an asset you need.

What should I do if I discover a mod I published contains an unlicensed asset?

Unpublish or make the mod private immediately. Replace the unlicensed asset with a properly licensed one or obtain retroactive written permission from the rights holder. Once the asset situation is resolved, republish the mod with the corrected attribution documentation. If the rights holder has already contacted you, communicate the remediation steps to them before republishing.

What is the difference between a license and an agreement?

A license is a unilateral grant of permission from the rights holder — the rights holder grants permission without requiring the recipient to sign or agree in writing. An agreement (contract) is a bilateral instrument requiring assent from both parties. Creative Commons and MIT licenses are licenses in the unilateral sense: by using the asset according to the license terms, the user accepts the terms without requiring a signed document. A separately negotiated written permission for proprietary asset use is typically an agreement.

If the asset author posts it publicly, isn't that implied permission?

No. Public posting is not implied permission. Copyright holders routinely post their work publicly on portfolio sites, social media, and asset libraries without granting any license to reproduce, distribute, or modify the work. Only an express license — written in the file, on the page hosting the asset, or communicated directly to the modder — constitutes permission.

Maintaining attribution over time

Attribution documentation requires ongoing maintenance. A mod published today with correct attribution may, over time, develop attribution gaps through:

• Asset replacement. A modder replaces a texture mid-development but forgets to update the Workshop description's Asset Credits.
• License change. A rights holder changes the license on an asset after the mod has already been published. Changes to CC licenses are generally version-specific and do not retroactively revoke previously granted licenses; however, a rights holder who upgrades an asset from CC-BY 3.0 to CC-BY 4.0 expects citations to the applicable version.
• Rights holder name change. An artist changes their username or rebrands. The attribution as written may no longer accurately identify the creator.
• Source URL death. The URL cited in the attribution becomes a 404. The attribution block should be updated with an archived URL or a note that the original source is no longer available.
• Collaborative mods. When multiple contributors work on the same mod, each contributor's asset sources must be tracked and attributed. Contributors who add assets mid-development must be required to document their assets in the asset log at the time of contribution.

57 Studios attribution review cadence

57 Studios conducts attribution reviews on published mods whenever a substantive update is released. The review confirms that all assets in the current version of the mod are documented in the Workshop description, that all attribution blocks are accurate, and that no new third-party assets have been added without documentation. This review is completed before the updated mod is published.

Responding to an attribution correction request

Occasionally, a rights holder will contact a modder to request a correction to the attribution provided for their work — a name change, a preferred citation format, or the addition of a missing element. The appropriate response is:

1. Acknowledge the request promptly (within 48 hours where possible).
2. Update the Workshop description's Asset Credits section to reflect the corrected attribution.
3. Confirm the update to the rights holder once it has been published.
4. Update the project's asset log to reflect the corrected information.

Prompt and cooperative responses to attribution correction requests preserve the relationship with the rights holder and reduce the likelihood of escalation to a formal DMCA notice.

A documented history of cooperative attribution behavior is also useful context if a misunderstanding later results in a formal DMCA notice — it demonstrates good-faith compliance practices, which may be relevant to the notice response. See How the Steam DMCA Process Works for the full response framework.

Cross-references

• Derivative Works and Reskins — the next article; covers what constitutes a derivative work and the analysis framework for reskins.
• How the Steam DMCA Process Works — the previous article; covers the DMCA process and how to respond to takedown notices.
• Smartly Dressed Games Modding Policy — the article covering SDG's documented position on community content.
• Steam Workshop Submission — the article covering the Workshop publication process, including description formatting.
• Project Folder Structure and GUIDs — the folder layout article; covers how to organize mod files including license documentation.
• Official Unturned modding documentation: https://docs.smartlydressedgames.com/en/stable/ — the authoritative source for Smartly Dressed Games' documented position on community content and asset use.
• Unturned on Steam: https://store.steampowered.com/app/304930/Unturned/ — the Steam store page; also the gateway to the Workshop where mods are published and distributed.

Closing note

Asset licensing and attribution are the foundational compliance layer for every Unturned™ mod that uses third-party content. The framework is not complicated — it requires knowing the license, satisfying its conditions, and documenting both clearly in the Workshop description. The time investment to do this correctly at the start of a project is small relative to the time required to remediate a published mod after a rights holder complaint or DMCA notice.

57 Studios treats attribution as a professional standard, not a bureaucratic obligation. Crediting the artists, sound designers, and tool builders whose work contributes to a mod acknowledges the creative labor that made it possible. The community infrastructure for sharing assets — open-content licenses, attribution norms, rights-holder communication practices — works best when everyone in the community participates in maintaining it.

The next article in this series, Derivative Works and Reskins, applies the licensing foundation established here to the specific question of when a modification of an existing asset creates a new copyrightable work and what obligations accompany that creation.

Modders who are new to the licensing landscape and want to understand how the Steam DMCA process connects to the attribution requirements covered here should start with How the Steam DMCA Process Works. Modders building mods with complex third-party asset stacks — particularly mods with mixed CC license families or any proprietary components — should complete the pre-publication checklist in the Practical Workflow section above for every release, including incremental updates, not only for initial publications.

Document history

Version	Date	Author	Notes
1.0	2025-08-14	57 Studios	Initial publication. Core licensing frameworks and attribution convention.
1.1	2025-11-20	57 Studios	Added license compatibility matrix and mixed-license appendix.
2.0	2026-05-18	57 Studios	Major revision. Added attribution block templates, pre-publication checklist flowchart, and FAQ expansion.
2.1	2026-05-18	57 Studios	Added commercial asset pool guidance, asset source table, license version differences section, and attribution maintenance section.