Breast Expansion - Wan

Announcing my first Wan 2.2 LoRA, a Breast Expansion body transformation LoRA.

I know there are a couple other similar LoRAs out there (here and here), but I've been wanting to make a model like this ever since AI videos started to become a thing, only I didn't have the hardware to create full motion LoRAs. Now, thanks to a musubi tuner installation that I discovered from this model page, I was able to create my first Wan 2.2 motion LoRA. Finally!

Important: This model is 100% fictitious and is not based on images or videos of any real person. In fact, every video in my dataset was created in AI with the heads out of frame to avoid biasing the faces. No images or videos (neither actual nor AI-generated) of any real person were ever involved in the making of this model. LoRA dataset available on request.

Trigger word: brstgrw ("breastgrow" with the vowels removed)

Helpful phrases: "Her body is slowly changing", "Her bust slowly grows bigger", "Her breasts slowly grow bigger", etc.

Strength: 1.00 in High Noise ONLY

Where is the Low Noise model?

There is no Low Noise model.

At least not yet. Why? Because you don't need one. All my test videos using only the High Noise model are looking amazing so I saw no need to spend the extra hours it would take to train a Low Noise model that might not even help. Please trust me on this. All of my sample videos were made with only the High Noise LoRA set to 1.00. I used lightx2v for acceleration in both high and low noise, and I used Boob Physics in low noise. That's it, no other LoRAs needed. There is only one exception, a video I included to show that this LoRA can mix with other action LoRAs, and the settings are called out in that video if you look at the details.

This model is very reliable, as long as you remember to prompt for growth. More prompt guidance below. The model is not picky about faces, races, or body types, so please do use this model to make your favorite ladies more busty no matter what color skin or where they came from. The model also works well with Image-to-Video and I included one such clip in the Sample videos, featuring Sophie hanging a Christmas ornament.

Negative points: Many of the women in my videos have navel piercings and I swear it's not my fault. None of my training videos included piercings of any kind (or tattoos) so that's all Wan's fault. It's more likely to show up when you use lightx2v acceleration since the negative prompts are ignored with CFG 1.0. If you really want to avoid the piercings, your best solution is to do full-length Wan renders without acceleration so you can set CFG higher and put piercings in your negative prompt. Next point: It's hard to control the size of the expansion. Changing the strength of the LoRA doesn't seem to be very related to the final size. Instead, dropping the strength is more likely to just make the animation less smooth. Maybe a low noise model would help here, I'm not sure. If you really want to reduce the effect, you can work around this by changing how many steps you give to the high noise vs. low noise. My sample videos are all 4 steps / 4 steps. If you go with 3/5 or 3/6 or some other uneven split, you can reduce the impact of the high noise body shape.

Prompt guidance

The more times you use the word "breast" or "breasts", the more likely you are to have naked breasts popping out of clothes. If that's what you want in your scene, then this is how you achieve it. If you want clothed expansion it's more tricky since you have to avoid that word. I use "bust" and "chest" and it seems to help most of the time, although that's not 100% reliable. Still, it's much more likely to give you clothed expansion if you use those words instead of "breast". Beyond that, just trust in Wan's language interpreter. It's pretty good at natural language and almost any description you can come up with will work. Be creative! And share your videos, I really want to see them. Seriously, post those videos here so I can see them too.

One final word: This model does work somewhat in Wan 2.1 as well, which means you can use it in things like InfiniteTalk and Wan 2.1 Vace and so on. However, it's not perfect, and that's the main reason I'm considering training a Low Noise model as well just to make that work better.

I hope you all enjoy the new model!