Debugging Unreal Blueprints

Unreal Engine has a visual scripting language called Blueprint. You have logic nodes that are connected together, contain decision logic, and can perform different tasks.

It’s a programming language, but instead of text and symbols, it’s nodes and connecting lines. You can end up with spaghetti code that actually looks like spaghetti. You’ll also eventually need to debug the code.

Since you can run your games from within the Unreal Editor, there is a Blueprint debugger provided. It has most of the usual features: breakpoints, call stack, variable inspection, Step Over, Step In, Step Out, etc. Since a Blueprint can have more than one active instance, you can switch between instances with a drop-down menu.

There is no remote debugging or attaching to other processes. You also cannot debug blueprints in a standalone game. You can use logging since Blueprint has a handy “Print String” node.

There is a great resource on Blueprint debugging, as well as other debugging topics specific to Unreal here.