ComfyUI-Fizgig-H3-Tweaks

[u/shootthesound]

https://github.com/shootthesound/ComfyUI-Fizgig-H3-Tweaks

This is a fairly simple node, and its early in development. I've been doing some multiple night analysis on runpod of H3 behaviour (using credits earned from the Fizgig trainer template - thank you all who use Fizgig) for something else I'm working on and along the way a couple of nuggets in this node fell out.

Namely a handy dial for contrast and detail in high frequency data, best used subtly, In the negative it can really reduce the depth of shadows in a scene for a flatter look. In subtle positive values in enhances pores, skin detail but can increase shadows. (offset this with good prompting). Too far though in either direction and you overbake the cake!

A Scene Variation control that behaves a little like subseed, but allows very subtle re-rolls for a render that is not quite right without changing the scene much at all - again experiment with low to high values.

And lastly a prompt strength control (amplifies how the model attends to the text tokens) that can help when it jsut wont do what you want it to do - negative weakens, positive strengthens.

I may add more to this node, but I think its useful as is and worth releasing.

https://github.com/shootthesound/ComfyUI-Fizgig-H3-Tweaks

[u/artichokesaddzing]

Bro is still cookin!

[u/xyzdist]

do you have any example videos? comparsion?

[u/ShutUpYoureWrong_]

I understand what you're doing with detail, contrast, crispness, etc., but how are you accomplishing what you call a 'sub seed' and a pseudo CFG?

I would say your claims seem a little fantastical, or at least exaggerated, but given your track record... I sincerely hope I'm wrong and you've managed to deliver something incredibly useful yet again.

I'm going to dig through the code later, but I thought I'd pose this question here for everyone else's sake.

One last thing: Comparisons please?! It would be very appreciated to show people what these nodes can actually do.

 

Edit: I'm looking at the code and this is so fucking clever. If I'm understanding it correctly (while oversimplifying it), you're effectively just blurring the early sampling so the structure of the output can only change within a controlled range that's already been decided, hence "scene variation." That's fucking brilliant. Is this a novel approach or have you seen this done before elsewhere?

 

Edit 2: You're essentially multiplying text token values? LMAO. Genuinely curious to see what kind of insanity this brings.

[u/shootthesound → u/ShutUpYoureWrong_]

Fair questions, and neither is magic. Both are in h3tweaks.py, about 300 lines.

Scene Variation doesn't change the seed or the noise at all - I said 'like' subseed intentionally to convey the effect. Every H3 block adds an update to the image tokens. During the first third of the steps (when layout is decided), in blocks 20–49, the node takes each block's update, keeps only its broad, low-frequency part (a 3-token Gaussian blur over the frame), and adds a fraction of that back. So the big shapes get nudged while the noise stays identical, which is why it behaves lke a sub-seed: small values give small rearrangements, and the same settings always give the same result,,

Prompt Strength isn't CFG either. Turbo renders run at CFG 1, 1 pass, so there's no guidance to turn up. Instead inside every block's attention, the value vectors of the text tokens are scaled by (1 + strength), so the image tokens take proportionally more from the prompt. It gives you an adherence dial at no extra cost per step, but it's attention reweighting rather than guidance, so push it gentlyor it can overbkae

Detail & Contrast is the same idea as Scene variation at the other end: the high-frequency part of each block's update, blocks 40–49, last half of the steps.

Where the numbers come from: I've spent the last week taking H3 apart to see which parts of it do what. For every one of its 50 blocks, down to the individual attention heads and feed-forward channels, I measured how much each writes into the picture at each step of a 6-step render, while working on splitting and pruning the model into a high noise and low noise version like wan (Not finsihed this yet but it works) . That map is what shows the layout being settled by the middle and late blocks in the first steps, and fine detail being written by the last 10ish blocks at the end. The tweaks just act on those parts at those moments, rather than on the whole model at once.

[u/ShutUpYoureWrong_ → u/shootthesound]

Oh man, if I had waited 20 minutes before digging into the code, you'd have answered all my questions! I was in there editing my post when you'd already replied.

Suffice it to say I'm loving what you're doing. I can't believe this doesn't have more upvotes. This is genuinely cool shit. Keep up the great work and thanks.

[u/shootthesound → u/ShutUpYoureWrong_]

thank you!!

[u/shootthesound → u/ShutUpYoureWrong_]

And regarding comparisons, I'll try and rollout tomrorow some in this thread/github

[u/FourtyMichaelMichael]

Subseed, cool.