Random values in Blueprints

#gotchas

Random values in blueprints are a common beginner trap as a result of How blueprint evaluation works.

Problem §

The typical problem is like this:

1. You have some blueprint nodes using a random value
2. It seems that the random value is inconsistent, and you get different random values for “no reason”, or some other behavior where the logic using random behaves in a weird way.

Solution §

If you use random values in blueprints, be careful to never connect it to more than one pin - directly, or through another pure node.

If you need to use the random value in multiple other nodes, or if you are unsure or seeing weird behavior, save your random value into a variable. If you use a variable instead of the random node, the value will remain consistent until you assign a new value into the variable.

See also §

For further explanation of why this happens, see How blueprint evaluation works