Mpi Float

Some nodes exist to do one boring thing extremely well, and MpiFloat is that node: a float in, the same float out, nothing else. No math, no conversion, no side effects. It's a value source and a wire fanner-out in one, and once you're building workflows with more than a handful of nodes you'll understand exactly why it exists.

Why a pass-through node is worth having

ComfyUI lets you type a number straight into a widget, and for a single use that's fine. The problem is repetition. When your denoise strength needs to feed the sampler, a reroute, and a filename note, typing it into each widget separately means changing it in each place - and the first time you forget one, you get a silent mismatch. That's the problem the primitive/pass-through family solves: break the value out of the widget, and it becomes one authoritative source you can fan out from a single socket.

MpiFloat is the float member of that family in this pack (alongside MpiInt, MpiString and MpiText). Its single float input defaults to 0, and its single float output just hands it back.

The one trick worth knowing

You can leave the input unconnected and just type into the widget - the node still emits that value. That makes it a pure constant source: drop one in, type your number, fan it out to five nodes. If you ever change the value, you change it in exactly one place. There's no control_after_generate to worry about here, no caching surprises; the output is stable until you edit the widget.

The sibling nodes in this pack are what you use when the socket types don't line up: if you have an int that a FLOAT socket won't accept, MpiConvert will give you the float version. MpiFloat is for when you already have the right type and just need a clean, labelled source for it.

Where people get burned

Not much to burn on, honestly - it's a pass-through. The one habit to avoid is treating it as a math node. It won't round, clamp or scale for you; feed it 0.7324 and you get 0.7324 back, not anything prettier. For rounding, MpiConvert; for clamping, MpiClamp; for shaping a 0–1 value, MpiExpoFloat. This node's job is plumbing, not math.

Install

From the MadPonyInteractive/ComfyUi-MpiNodes pack. ComfyUI Manager → search ComfyUi-MpiNodes (publisher mad-pony-interactive), install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/MadPonyInteractive/ComfyUi-MpiNodes

then restart. Zero dependencies, no models to download. The pack is AGPL-3.0 (≤ 1.2.6 MIT) and is the node collection behind the author's Cubric Vision app.

The verdict

If you're building one-off test graphs, skip it - the widget on the target node is fine. The moment you're building something you'll reuse, where a strength or scale value needs to live in one place and feed many, MpiFloat (or its int/string siblings) is the right call. It's invisible, it's boring, and it's exactly the kind of plumbing that keeps a growing workflow from turning into a source of silent bugs.