Signifying inheritance

At the value level:

• it is not always required to overtly signify that a value is inherited at first glance.
  
  consider whether it is useful to use additional visual signifiers to indicate to the user that a value is inherited; though additional visual signifiers can be useful, consider whether they add unnecessary visual clutter and whether they are useful to all users, or only a small subset of users
• provide information that a value is inherited to users upon further interaction, for example in a tooltip on hover

An example showing overrides in a Prefabs inspector header compared to a mini inspector

Manipulating inheritance

Inheritance relationships are typically manipulated and managed at the object level.
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Creating an inheritance relationship
‍Parent objects are usually stored as assets in the Unity project.

There are typically two ways that parent objects can be created:

• A user may create a parent object asset in the Unity project, and create or link instances from that asset
• A user may create a regular object in its primary context (eg. a GameObject in the scene), and choose to convert it to an original object (eg. Prefab)
• If a regular object is converted to a parent object, a parent object asset will be created, and the regular object will be converted to an instance of that parent asset

Deleting an inheritance relationship is known as detaching:

• When an instance is detached from its parent object, it retains the values it had at the time of detaching, and changes made in the original object from that point forward do not get reflected in the instance
• If inherited values are overtly signified in the UI, then inheritance signifiers should disappear when the instance is detached; override signifiers should also disappear

Multiple inheritance levels

It is possible for multiple levels of inheritance to exist. One type of multi-level inheritance is variants.

• For simplicity, only provide the user with the final resolved value at a glance
• Provide more detailed information to users upon further interaction
• For example, if a value can inherit from multiple sources, provide what those sources are, and in what order those sources will apply to the value

When to use overrides

Overrides represent a specific inheritance concept in the Editor, and is expressed through a specific set of UI and UX features.

Do not use override UI patterns in features that do not make use of the conceptual model of overrides and inheritance as defined above.

What is not an override:

• Overrides only exist when an inheritance relationship exists between an object and its instance
• If an object’s instance does not preserve the relationship with its parent object (ie. in the example of a copy-pasted or cloned object), then overrides may not be set on the instance

Do not use the override pattern just to indicate “this line is different”:

• The visual design pattern that the override bar uses is a common design solution in the Editor
• The override bar is often incorrectly used to denote that an inspector property field is different from the rest around it. However, if the use case does not truly reflect the conceptual mental model of an override, refrain from using the override bar UI. Explore other options to visually indicate that an element is different, taking fundamental design guidelines -> and accessibility -> into account.
  
  ‍See overrides anatomy ->

At an object level, provide an aggregate view of all overrides on the object so that the user may work efficiently.

See the Overrides at an object level section ->

Manipulating overrides

At a value level:

• allow the user to compare overridden values to inherited values
• allow the user to revert overridden values to inherited values
• allow the user to push overridden values back to the original parent object so that other child objects will inherit the overridden value
• provide these options to the user in-context; for example, in a context menu on the value directly

An example showing overrides in a Prefabs inspector header compared to a mini inspector

Create, modify, and apply material variants
For more information on creating material variants, visit material variant tasks ->

At an object level:

• provide a consolidated view of all overrides on the object so that the user may work efficiently
• allow the user to manipulate overrides using a consolidated view of all overrides on the object
• allow the user to accomplish the same actions as at the value level; for example, in a Prefabs overrides dropdown

An example showing overrides in a Prefabs inspector header compared to a mini inspector

An example showing overrides in a Prefabs inspector header compared to a mini inspector

When to use variants

Consider implementing variants in your feature if it will be heavily used by medium- to large-sized production teams, where multiple users with different responsibilities access a single Unity project.

Signifying variants

Iconography
Variant assets in Unity are marked with an icon that is a variation of the parent object’s icon. Variants have a distinct, consistent visual language applied to the parent object’s icon.

Show the lock icon next to a locked property and disable the property UI

Inheritance Tree View

• Follow the same general principles for signifying multi-level inheritance relationships
• For variants, consider using the inheritance tree view, which allows the user to see the inheritance tree of any variant, including all its parent objects and all its variant child objects

Show the lock icon next to a locked property and disable the property UI

Manipulating variants

Creating variants

Typically, variants are stored the same way as other parent objects: as assets in the Unity project.
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There are typically two ways that variants can be created:

• A user may create a variant of a parent object
• A user may create an instance of a parent object, and choose to convert it to a variant
• When the original instance is converted to a variant, a variant asset will be created, and the original instance will be converted to an instance of that variant asset
• The original instance’s overrides will become regular values set on the variant that its instances inherit from

Create, modify, and apply material variants
For more information on creating material variants, visit material variant tasks ->

Show the lock icon next to a locked property and disable the property UI

Show the lock icon next to a locked property and disable the property UI

Deleting Variant Relationships (Detaching)

• A variant may be detached from the parent object it inherits from
• When the variant is detached from its parent object, this breaks the inheritance relationship between the variant and its parent object, but preserves the inheritance relationships between the variant and its child objects
• When the variant is detached from its parent object, it becomes a parent object asset instead of becoming a variant asset

When to use override locking

You might consider implementing override locking in your feature if your feature will be heavily used by medium- to large-sized production teams, where multiple users with different responsibilities access a single Unity project.

Signifying on instances

• Show the lock icon next to a locked property, and disable the property UI.
• Explain to the user where the override lock is coming from.

Show the lock icon next to a locked property and disable the property UI