Best way to do a weight gain sequence with AI?

[Burguesa]

What would be the best way to make a weight gain sequence with AI? I’ve been using some AI like stable diffusion, chatgpt-5, charhub, and I don’t really know what I have to tell them to simply make a character look 120lbs and not 200lbs hahaha, I’m making a game in renpy and since I don’t have much money I can’t afford to pay an artist to do the images for the game, so I opted to try to use images made by AI, but I feel like they are super inconsistency, and I’ve seen a lot of people on deviantart doing weight gain sequences with AI AND IT LOOKS AMAZING HAHAHA, I don’t know what I’m doing wrong…

(If I don’t find how to do that, I’ll have to learn how to use VaM (because I have it) but the truth is if I use VaM I’m also going to want to make my own backgrounds, and that will take too much of my time)

[Megaton.Melon]

The trick to making sequences is by using the same seed with slightly different prompts. I use mage.space but its kinda expensive these days for custom inports there. most of the battle is definately the prompting so Ill give you an example of how I prompt:

Hyper detailed, full body shot of a young (woman in her 20s:1.2), She is wearing a plain white tank top that shows her cleavage and camo pants, She has long wavey blonde hair, moderate bust, thick waist, cherubic face

Then I’d generate until I am happy with it and then inpaint the image to remove anything like extra fingers or to touch up something that looks off. Then I freeze the seed and start adding to my prompt:

Hyper detailed, full body shot of a young (woman in her 20s:1.2), She is wearing a plain white tank top that shows her cleavage and camo pants, She has long wavey blonde hair, moderate bust, thick waist, cherubic face, overweight, double chin, (fat girl:1.4)

But its always worth learning a new skill. I am making a game myself and I am no artist but I am doing everything by hand and it feels great to see things come together that youve hand crafted.

[Ares42]

A lot of it comes down to the model you’re using. I mostly use Hyperfusion V9. And like @Megaton.Melon said - the seed really makes the difference for the sequence for general consistency. If you want variety in your fatties I’d recommend a model that has been trained for it rather than a generic model.

What I tend to do is try a few runs through with no weight tags for the “starter weight” to get a general look I like then bump the weight up and see if it still looks good. If I’m struggling to get a look that I like that works this way I’ll start at the opposite end of the scale and work backwards using that seed and - rarely - I’ll go for the middle of the sequence and sort of “spread out” to the lower and upper ends of the sequence. If all else fails for a particular pose for a sprite I’ll randomise the seed and do it until I get one that is “close enough” to both the look pose I want and the general look of the character.

Here’s a couple of examples:
Stage 1:
best quality, high rating, solo, (perfect anatomy:1.6), photorealistic, no_background, detailed, gorgeous face, viking, (braided hair:1.2), blonde hair, long hair, (beautiful green eyes:1.2), perfect eyes, (shaved side of head:1.2), viking warrior clothes, metal bra, bracers, (loose brown pants:1.2), (Viking tattoos on arms:1.4), standing, bare arms, front view, frontheavy, big breasts, heavy breasts, bare belly, (fighting_stance:1.4), grinning_at_viewer, sweaty, fists up

Stage 2:
best quality, high rating, solo, (perfect anatomy:1.6), photorealistic, no_background, detailed, gorgeous face, viking, (braided hair:1.2), blonde hair, long hair, (beautiful green eyes:1.2), perfect eyes, (shaved side of head:1.2), viking warrior clothes, metal bra, bracers, (loose brown pants:1.2), (Viking tattoos on arms:1.4), standing, bare arms, front view, chubby, frontheavy, big breasts, heavy breasts, bare belly, legs apart, deep_navel, detailed_navel, (belly_folds:1.2), (fighting_stance:1.4), grinning_at_viewer, (sweaty:1.2)

Stage 5:
best quality, high rating, solo, (perfect anatomy:1.6), photorealistic, no_background, detailed, gorgeous face, viking, (braided hair:1.2), blonde hair, long hair, (beautiful green eyes:1.2), perfect eyes, (shaved side of head:1.2), viking warrior clothes, metal bra, bracers, (loose brown pants:1.2), (Viking tattoos on arms:1.4), standing, bare arms, front view, obese, double_chin, frontheavy, extra large breasts, heavy breasts, fat rolls, thick thighs, bare belly, legs apart, two fold navel, sagging belly, cleavage_overflow, skindentation, overflowing_breasts, fat_belly, (fighting_stance:1.4), grinning_at_viewer, (sweaty:1.5), fists up

[JakobY]

I use InvokeAI, which runs locally, and has some great options for keeping sequential images in line with previous ones…

1 - You can lock the seed and increment the text a bit.
2 - You do inpaint from the previous stage up into the next one, so each step along the ladder is based 80% on the one preceding it.
3 - There’s a lot of posture or facial composition elements you can call (ControlNets, etc) that keep your character similarly posed and their face generally consistent.
4 - There are ControlNets (Canny, Depth, etc) and/or image-to-image generations that let you essentially tell the system “Generate an image whose character has the same body type/outline as THIS other image’s character, for the first 10% or so of your work, then follow my prompt text for the rest”. Once you have a decent ‘progress’ series of the morphology you want, that’s a huge timesaver. It also has some built in posturing, which is handy if you’re doing a typical VN setup visually.
5 - You can get a lot of mileage by using an online thesaurus, looking up the particular type of chubbiness you’re aiming for, and dumping every reasonably consistent word into one sentence with a weight adjustment on it that starts at maybe 0.8 and creeps up ~0.04 each iteration, up to ~ 1.2 or so. Use the same seed and prompt and you’ll generally get very similar output that looks progressively closer to the final state you were going for.

[Burguesa]

@Megaton.Melon @JakobY @Ares42
Thanks for the quick replies, this is exactly what I needed to know about. Especially the thing about the seeds, I was super lost without that lol, programming the game for me is the easiest but the artistic part of the game is what gives me problems, even so as megaton commented I am going to learn to use VaM to make my own scenarios and models for my game, even so knowing all this about AI will help me give me more ideas of the characters I want in my story, thank you so much