Changing the transform of instanced mesh instances after adding them

Development Programming & Scripting C++
1

I can not find a way to change the transform of instances of an instanced mesh after adding them.
How can you access the instances after creation to modify their position?

2

All of this is in instancedstaticmeshcomponent.h

To move ALL instances at once by some delta:


virtual void ApplyWorldOffset(const FVector& InOffset, bool bWorldShift)

To access the instance data:


/** Array of instances, bulk serialized */
UPROPERTY(EditAnywhere, Transient, DuplicateTransient, DisplayName="Instances", Category=Instances, meta=(MakeEditWidget=true))

TArray<struct FInstancedStaticMeshInstanceData> PerInstanceSMData;

Relevant part of struct used above in the TArray


USTRUCT()
struct FInstancedStaticMeshInstanceData
{
	GENERATED_USTRUCT_BODY()

	UPROPERTY(EditAnywhere, Category=Instances)
	FMatrix Transform;
3

It looks like that API just doesn’t exist yet. I will add it to our task tracker, but do note that it will be a fairly costly operation, because it will have to update the whole transform list.

4

Thanks for the replies!

For now I’ll expose the PerInstanceSMData myself, but it would be great if it would be part of the public API in a future version.

I only need to update about 10 instances out of 10000 every 1 second, so the operation being costly should not make a big difference.

5

I added Blueprint APIs to get or update the current transform for an individual instance. This will be in 4.4

6

Ohhhhhhhhh thank you thank you thank you thank you.