NOR

NOR is "NOT OR," and it's the mirror image of the pack's NAND: it returns True only when both of its inputs are False, and False in every other case. In plain English it answers the question "is neither of these things happening?" Which, once you start building conditional workflows, comes up more often than you'd guess.

When you'd actually use it

Say you're building a workflow with a fallback branch. You want it to trigger only when two candidate sources both failed to produce anything - no image from the img2img path and no image from the upscale path. That's "neither is true," which is exactly what NOR computes. The output stays True only while both inputs are False, so it behaves like a "nothing else fired, so do the fallback" flag.

It's also the natural gate for "skip if either condition is active." Wire your two "please skip" flags into a NOR and the result flips to False the moment either one trips, which you can feed straight into a switch as a condition. Same job as OR into NOT, but a single node instead of two.

The practical truth, like its cousin NAND, is that you'll use OR, AND, and NOT far more often. NOR is there for the occasional inverted gate and for the people porting over logic from other node packs - and when you need it, it's nice that it's one clean node.

How it works

Straight Python not (a or b), two boolean inputs and one boolean output, no state and no dependencies. The author's description: "Returns True only if both inputs are False (NOT OR)." It lives in the SimpleLogics/Logic category with the rest of the gates.

The inputs that matter

Both are required BOOLEAN inputs, defaulting to False:

• a - first boolean
• b - second boolean

One BOOLEAN output, typically wired into a switch node's condition socket or into another logic node.

Installing it

Standard for this pack: danipisca07/ComfyUI-SimpleLogics is a small, dependency-free pure-Python pack - no requirements.txt, no model downloads. Grab it from ComfyUI Manager (search "SimpleLogics") or:

cd ComfyUI/custom_nodes
git clone https://github.com/danipisca07/ComfyUI-SimpleLogics

Restart ComfyUI and you're done.

Common issues

Nothing to break here - boolean gates either work or they're the wrong gate. The classic mix-up is expecting NOR to behave like OR and wondering why the fallback never fires; remember NOR is true only when both inputs are false. Also note the pack registers an undocumented GeoCalib camera node alongside these; it's unrelated and safe to ignore. That's about all the troubleshooting there is for a two-input gate.