Batch Float (mtb)

If you've ever wanted a value to change smoothly across a batch of frames - a zoom that eases in, a denoise strength that ramps down, a mask opacity that fades - Batch Float is the node that makes that list of numbers for you. It's part of MTB Nodes' mtb/batch family, melMass's corner of the ecosystem for building animated ComfyUI graphs frame by frame rather than one image at a time.

What it does

You give it a range and a count, and it hands back a FLOATS list - one value per step - following an easing curve you pick from a dropdown. That list is the currency a lot of animation-oriented mtb nodes trade in: feed it into Batch Time Wrap as the retiming curve, into a per-frame denoise or CFG schedule, or into anything downstream that expects "one number per frame" instead of one fixed number for the whole batch.

The inputs and output that matter

• mode - Steps interpolates from min to max across count values using the chosen easing; Single is the flat case, useful when you want a constant-value FLOATS list of the right length just to satisfy a downstream node's shape expectations.
• count - how many values to generate, i.e. how many frames this curve covers.
• min / max - the range the curve travels between.
• easing - 22 choices, from plain Linear through the Sine/Quart/Cubic/Circ families in In/Out/In-Out variants. This is the same easing vocabulary you'd find in any animation or motion-graphics tool: Linear moves at constant speed, *_In starts slow and accelerates, *_Out starts fast and decelerates, *_In/Out does both - ease in, hold speed, ease out.

Output is a single FLOATS list - not an IMAGE, so this node produces no pixels on its own. It's a curve generator, meant to drive something else.

Installing it

ComfyUI Manager: search MTB Nodes, install, restart. By hand:

cd ComfyUI/custom_nodes
git clone https://github.com/melMass/comfy_mtb

then restart ComfyUI. No model downloads involved - this is pure Python math, no weights to fetch.

Common issues

The most common mistake is a mismatch between count and however many frames your batch actually has downstream - if Batch Float generates 25 values but your image batch has 40 frames, whatever consumes the FLOATS list will either error or silently only use part of it, depending on the node. Match count to your frame count first, then tune the easing.

Second: this pack is large and doesn't stop loading on one broken node - it logs [comfy_mtb] Some nodes (N) could not be loaded at startup and a pointer to http://127.0.0.1:8188/mtb, and keeps the rest running. Other users have hit exactly that message in practice, so if Batch Float isn't in your node list after install, check that console line before reinstalling - it's almost always a missing dependency for a different mtb node, not this one, since Batch Float itself has none.

If you want a hand-drawn curve instead of a preset easing function, pair this with Curve and Curve To Float instead - those take an actual drawn curve rather than a formula, at the cost of the pack marking that path as still work-in-progress.