Sigma Waveform Node Advanced

The base Sigma Waveform Node draws one wave. The Advanced version from the SigmaWaveFormNodes pack draws two, blends them, and then runs the result through a small post-processing pipeline that makes it look a lot more like something a sampler can actually chew on. If you're going to bother with this pack at all, this is the node you'll end up keeping.

The idea: one waveform shape is a blunt instrument. A sine schedule gets boring, a square schedule gets violent. But a sine faded into a sawtooth, at the right blend, can give you a curve that starts aggressive and settles - which is exactly the arc a good scheduler fakes with math. This node lets you build that arc by hand.

How it works

It generates two independent waveforms on the same time axis, then combines them:

sigma = blend_factor * sigma1 + (1 - blend_factor) * sigma2

After the blend, the same pipeline as the base node runs - unidirectional shift, optional exponential damping, optional Fourier lowpass - and then the Advanced node adds two things the base node doesn't have:

• apply_loglinear - interpolates the sequence in log space, the classic move for turning a linear-looking curve into a perceptually smooth noise ramp.
• The "refined exponential solver" - a second-order integration pass that sums the curve into a smoother, more schedule-shaped output. This is why the Advanced node's results are noticeably less chaotic than the base node's raw waves. It runs unconditionally.

Finally noise_fine_tune scales the whole thing.

The inputs that matter

The base-node set is all here - steps, min_sigma, apply_fourier, horizontal_length, enable_damping/damping_factor, enable_unidirectional - plus the split controls:

• waveform_type1 / waveform_type2 - pick any two of the seven shapes (sine, sawtooth, stepped, square, random, triangle, rectangular).
• amplitude1 / frequency1 and amplitude2 / frequency2 - shape each wave independently.
• blend_factor (0–1, default 0.5) - at 0.5 you get an equal mix; pull toward 1 to hear mostly wave one.
• noise_fine_tune (default 1.0) - a master volume for the whole schedule after blending and integration.
• apply_loglinear - off by default; turn it on when you want the interpolated, smoothed version.

Single output sigmas, which wires straight into ComfyUI's native SamplerCustom node.

Installing it

Comes bundled with the whole SigmaWaveFormNodes pack - install once, get all six nodes. Use ComfyUI Manager (search "SigmaWaveFormNodes") or clone it manually:

cd ComfyUI/custom_nodes
git clone https://github.com/BenNarum/SigmaWaveFormNode

Restart ComfyUI after. Dependencies are just numpy and torch, which you already have; no models, no downloads, nothing heavy.

Gotchas

Same caveats as the base node apply - even the Advanced node's output isn't a guaranteed-descending schedule, so treat results as experiments, not corrections. The blend formula weights wave one by blend_factor and wave two by 1 - blend_factor, so at 0.5 it's a true half-and-half, not two full waves stacked. And noise_fine_tune multiplies the final integrated curve, so a value of 2 roughly doubles your sigma magnitudes - start at 1 and nudge.

One honest note: this pack's last commit was June 2024 and the project is effectively dormant. It still imports and runs fine, but don't expect updates - and don't expect anyone on r/comfyui to have debugged your exact settings. You're the maintainer of your own workflow here, which is sort of the point.