UPROPERTY

Question 1

what are the specifiers for a UPROPERTY?

Answer 1

first = visibility or editability
second = BP accessibility 
third = categories

UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category= BallBearing)
UStaticMeshComponent* ballMesh;

you can only just one of each

Question 2

what specifiers do visibility and editability have?

Answer 2

They decide whether the class can just see it, or can edit it in BP.

EditAnywhere - property can be edited on archetypes and instances
EditDefaultsOnly = only on archetypes, not on instances
EditInstanceOnly = only on instances, not on archetypes
VisibleAnywhere = visible but cannot be edited
VisibleDefaultsOnly = visible for archetypes, not for instances, cannot be edited
VisibleInstanceOnly = visible for instances, not archetypes, cannot be edited

EditAnywhere and VisibleAnywhere are most likely

Edit and Visibility modifiers CANNOT be used together

You can only specify one per UPROPERTY

Question 3

what is an archetype and what is an instance?

Answer 3

archetype = classes and BPS
instances = literal instances of archetypes in the level

Question 4

what are the specifiers for accessibility?

Answer 4

BlueprintReadOnly = can be read by blueprints, but not modified
BlueprintReadWrite = can be read or written from a BP

Limit BP access where possible, for maintenence

Question 5

what is “Transient”?

Answer 5

Transient = keyword next to UPROPERTY that has a pointer pointing to a class derived UObject but doesnt access BP in anywhere

it just means its a temporary property - its a smart pointer that’ll delete on its own.

UPROPERTY(Transient)
UParticleSystemComponent* Sprinkles;

Question 6

what is the ‘meta’ specifier?

Answer 6

control how classes, interfaces, structs, enums and values can behave in different sections of the engine or editor

meta = (AllowPrivateAccess = “true”)

Question 7

what is a UPROPERTY()?

Answer 7

C++ Macro

Part of the UE Reflection system

Allows BP to edit values