Dear Skydive,
I’ve posted a tutorial on how you can change physics mass during runtime here!
Wiki Link
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Code from tutorial:
void AYourStaticMeshActorClass::SetMassScale(const float& NewScale)
{
if(!StaticMeshComponent) return;
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
FBodyInstance* BodyInst = StaticMeshComponent->GetBodyInstance();
if(!BodyInst) return;
//~~~~~~~~~~~~~~~~~~~~~~~~
// New Scale
BodyInst->MassScale = NewScale;
// Trigger Update!
BodyInst->UpdateMassProperties();
}