Factorio: separate a technology prerequisite from its science cost
A technology can be unavailable because its prerequisite is missing, even when you already have some of the science packs shown nearby. Read the technology tree as a dependency map and a consumption requirement. The two questions lead to different actions in the factory.
Original explanatory diagram. Read the full method and limitations below.
Locate the desired unlock first
Choose a technology that unlocks something you actually want to build in your current game. Inspect its information rather than relying on a name remembered from another version or mod. Write the unlock as a concrete goal, such as a particular machine or recipe. A named goal makes it easier to distinguish useful prerequisite work from researching unrelated technologies simply because they are currently available in the list.
Follow the prerequisite links
Trace the technology’s required earlier research through the tree. A prerequisite is a logical condition for access, not a physical item you can place in a chest. If an earlier technology is missing, identify the first reachable one along the relevant branch. Keep the chain short in your notes: target, immediate prerequisite, currently available step. You do not need to copy the whole tree to understand the next dependency that blocks your goal.
Read the science requirement separately
Once the prerequisite path is clear, inspect the pack types, quantities and research time associated with the relevant step. These describe the lab work needed, which is different from unlocking access. A factory can satisfy the prerequisite and still lack the required pack production. Conversely, a warehouse of packs does not remove a prerequisite. Keep the dependency note and the supply note in separate fields so that one does not silently replace the other.
Choose the next factory action
If the next prerequisite is researchable and supplied, selecting it may be the immediate step. If science production is missing, the next action may be building that supply. If you already unlocked the desired recipe, further research is not the answer to a machine-placement problem. End by stating one action and the evidence behind it. This keeps the technology tree connected to the actual factory instead of becoming a separate checklist of impressive-looking unlocks.
Illustrative worked example
Illustrative planning note: A player wants a fictional target unlock shown on their own technology tree. Their notebook records one unmet prerequisite and a separate missing pack type for the next available research. They choose to restore that pack’s production before selecting the available prerequisite. The example deliberately avoids inventing a named technology chain; the precise links should come from the player’s installed game and active mod set.
Questions that come up
Does owning a machine item prove its technology is researched?
Not necessarily in every scenario or modded save. Use the actual technology state rather than inferring the entire research history from one item.
Should I queue every visible technology?
That is a separate planning choice. This exercise focuses on understanding one goal’s dependency and supply needs before adding a larger queue.
References and scope
These sources support the factual background. Examples and exercises are original illustrative teaching material. References do not imply endorsement.
- Official Factorio Wiki: Research — Technology prerequisites and science requirements.