Model reference · open weights
shuttle-3-diffusion is an open-weight image model from shuttleai. shuttle-3-diffusion (BF16) weighs 33.7 GB; the smallest configuration that runs it is RTX 5090 32 GB.
For self-hosting, compare this build's requirements below with the GPU you plan to rent.
Summary of the shuttleai/shuttle-3-diffusion model card, 2026-10-01
What it is
| Released by | shuttleai |
|---|---|
| Released | 2024-11-12 |
| Parameters | 11.9B |
| VRAM | 33.7 GB for the weights |
What it runs on
| Card | One image | Memory |
|---|---|---|
| RTX 3060 12 GB … RTX 4090 24 GB | does not fit | |
| RTX 5090 32 GB | tight (encoders offloaded) | 31.0 GB |
| L40S 48 GB | tight | 44.0 GB |
| A100 80 GB | fits | 78.2 GB |
| H100 80 GB | fits | 78.1 GB |
| RTX PRO 6000 Blackwell 96 GB | fits | 93.8 GB |
| DGX Spark (GB10) 128 GB unified | fits | 107 GB |
| H200 141 GB | fits | 138 GB |
| B200 180 GB | fits | 176 GB |
From the model card
These model variants provide different precision levels and formats optimized for diverse hardware capabilities and use cases
Shuttle 3 Diffusion is a text-to-image AI model designed to create detailed and diverse images from textual prompts in just 4 steps. It offers enhanced performance in image quality, typography, understanding complex prompts, and resource efficiency.
You can try out the model through a website at https://chat.shuttleai.com/images
You can use Shuttle 3 Diffusion via API through ShuttleAI
Install or upgrade diffusers
pip install -U diffusers
Then you can use DiffusionPipeline to run the model
import torch
from diffusers import DiffusionPipeline
# Load the diffusion pipeline from a pretrained model, using bfloat16 for tensor types.
pipe = DiffusionPipeline.from_pretrained(
"shuttleai/shuttle-3-diffusion", torch_dtype=torch.bfloat16
).to("cuda")
# Uncomment the following line to save VRAM by offloading the model to CPU if needed.
# pipe.enable_model_cpu_offload()
# Uncomment the lines below to enable torch.compile for potential performance boosts on compatible GPUs.
# Note that this can increase loading times considerably.
# pipe.transformer.to(memory_format=torch.channels_last)
# pipe.transformer = torch.compile(
# pipe.transformer, mode="max-autotune", fullgraph=True
# )
# Set your prompt for image generation.
prompt = "A cat holding a sign that says hello world"
# Generate the image using the diffusion pipeline.
image = pipe(
prompt,
height=1024,
width=1024,
guidance_scale=3.5,
num_inference_steps=4,
max_sequence_length=256,
# Uncomment the line below to use a manual seed for reproducible results.
# generator=torch.Generator("cpu").manual_seed(0)
).images[0]
# Save the generated image.
image.save("shuttle.png")
To learn more check out the diffusers documentation
To run local inference with Shuttle 3 Diffusion using ComfyUI, you can use this safetensors file.
Shuttle 3 Diffusion can produce images better images than Flux Dev in just four steps, while being licensed under Apache 2. More examples
Shuttle 3 Diffusion uses Flux.1 Schnell as its base. It can produce images similar to Flux Dev or Pro in just 4 steps, and it is licensed under Apache 2. The model was partially de-distilled during training. When used beyond 10 steps, it enters "refiner mode," enhancing image details without altering the composition. We overcame the limitations of the Schnell-series models by employing a special training method, resulting in improved details and colors.
Quoted from the model card on Hugging Face. The full card is behind the Hugging Face link above.
Running it yourself
Rent a machine by the hour. ComfyUI is installed on it. Open ComfyUI through the tunnel and load the workflow from the model's card on Hugging Face; choose this model's file in its loader.
# on your rented machine: pip install diffusers transformers accelerate
import torch
from diffusers import DiffusionPipeline
pipe = DiffusionPipeline.from_pretrained("shuttleai/shuttle-3-diffusion", torch_dtype=torch.bfloat16).to("cuda")
image = pipe(prompt="a red bicycle on a cobbled street").images[0]
image.save("/workspace/out.png")
# on your rented machine (the ssh line is on its page in the console)
# get REPO FILE FOLDER: one file into /workspace/models/FOLDER, where ComfyUI loads it from
get() { hf download "$1" "$2" --local-dir /workspace/hf-files && mkdir -p "/workspace/models/$3" && mv "/workspace/hf-files/$2" "/workspace/models/$3/$4"; }
# the model (22.1 GB)
get shuttleai/shuttle-3-diffusion shuttle-3-diffusion.safetensors diffusion_models
start-comfyui
# on your computer, in a second terminal: ComfyUI in your browser at http://localhost:8188
# HOST, PORT and BOOKING are your machine's, from its page in the console
ssh -o HostKeyAlias=axforge-BOOKING -o StrictHostKeyChecking=accept-new -L 8188:localhost:8188 dev@HOST -p PORT