Considerations & performance

General

• Blueprint nodes execution are slower than C++ code.
• Pure nodes are executed each time they are used (they don’t cache the outputs like a impure node).
• Blueprint For loop is very slow because for each iteration it does a copy of the current entry.
• Inputs and outputs of nodes (pure, impure and Make/Break) are copied.
• BP doesn’t get optimized when compiled, it merges neighbor connections.
• BP is an array of uint8 in the background

Misc

• BP compiles into bytecode that runs on BP VM, with the ability to call into native code (blueprint callable, blueprint pure, etc… functions). Here “VM” is a glorified switch statement, see below screenshots.

Resources

More details

• Unreal Engine, and the hidden pitfalls of Blueprints
• Performance guideline for Blueprints and making sense of Blueprint VM