NextStep 1.1 Pretrain
NextStep 1.1 Pretrain exposes a separate training-stage checkpoint. Its repository includes the same custom pipeline layout and VAE download path as the finished 1.1 family.
Research release
A 256-pixel checkpoint is also published
StepFun also publishes NextStep-1.1-Pretrain-256px under Apache 2.0. Its example generates at 256 by 256 pixels. This pretraining variant is grouped here; the shared card does not establish that it has the final 1.1 model's post-training behavior.StepFun NextStep 1.1 Pretrain 256px model card
Keep final-model claims separate
The card repeats the family's reinforcement-learning improvements. The Pretrain name identifies a distinct stage; those final-model claims do not establish its own post-training behavior.StepFun NextStep-1.1-Pretrain model card
Use it to study later training
Practical guidance. This checkpoint is suitable when the question concerns how additional training changes image output. Keep inference settings constant between this stage and the completed release so the comparison does not mix training and sampling changes.
Specifications & access
| Detail | Value and conditions |
|---|---|
| Status | Research release |
| Access | Downloadable |
| Model identifiers | NextStep-1.1-PretrainNextStep-1.1-Pretrain-256px |
| License | Apache 2.0.StepFun NextStep-1.1-Pretrain model card |
| Stage | The published repository is explicitly named Pretrain.StepFun NextStep-1.1-Pretrain model card |
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- NextStep 1 Large Pretrain
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An image-generation pretraining checkpoint combining a 14B autoregressive backbone with a 157M flow-matching head.
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An autoregressive image-generation model trained with flow-based reinforcement learning.
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