🌀 BV Subgraph Spacer

BV Subgraph Spacer is a UI-only node that adds vertical whitespace to your graph. It doesn't process pixels, tokens, or anything else. You drop it in, stretch the graph around it, and suddenly your sections have breathing room instead of looking like a data-center rack.

This is the kind of node that sounds absurd until you've stared at a 40-node workflow for an hour. The ecosystem's own documentation flags unreadable graphs as the top beginner complaint about ComfyUI, and every serious QoL pack ships visual-cleanup tools. Spacers are the boring-but-real half of that: they give you room to arrange nodes into readable columns and sections, and they keep that layout stable when a reload would otherwise collapse everything into a pile.

Its real talent shows in Subgraphs. The README's whole pitch for the pack is that these UI nodes render correctly inside Subgraphs/Subflows - the spacer takes up space inside the subgraph and preserves the layout when the subgraph is viewed from outside. If you've ever opened a collapsed subgraph and found its internal layout scrambled, you know why stable whitespace is a feature.

How it works

The backend returns the spacer's height as a dummy STRING output and does nothing else. The visual height is rendered by a JavaScript extension, and - per the README - you edit the height by clicking directly on the spacer. The mechanism is purely cosmetic: it reserves vertical pixels in the canvas, full stop.

Inputs:

• height (INT, default 24, range 0–400) - the spacer height in pixels. This is the one you'll fiddle with.
• scale (FLOAT, default 1.0, range 0–5) - an optional multiplier applied on top of height. Handy if you want to scale a whole group of spacers uniformly without editing each height.

Output: a single _ STRING that just echoes height. It exists because ComfyUI likes nodes to have outputs; it's not data.

Install & gotchas

Same pack install as everything else: ComfyUI Manager → BV Node Pack, or git clone https://github.com/BlackVortexAI/bv_nodepack into ComfyUI/custom_nodes, restart, then Ctrl + F5 hard-refresh. The hard refresh matters - the spacer's click-to-edit and rendered height are JS extension behavior, and a cached frontend shows a plain number field instead.

The gotchas are proportionate to how simple this node is. If the spacer doesn't take up space, you haven't hard-refreshed. If it renders as a plain widget after a ComfyUI update, that's Nodes 2.0's fallback behavior (the pack's notes admit the new frontend may not expose the hooks these UI nodes need). And one honest caveat: since it's a real node in the graph, ComfyUI queues it like any other - a hundred spacers add a tiny, real amount of execution overhead. Keep spacers to the tens, not the hundreds, and it's free.