Step1X-3D
Fully open Apache 2.0 text-to-3D and image-to-3D: 1.3B geometry plus 3.5B texture models with training code included.
About
Step1X-3D, released by StepFun on May 13, 2025, is that rare thing in 3D generation: a genuinely fully-open system. The release includes the model weights (a 1.3B-parameter geometry generator and a 3.5B texture-synthesis model), the training code for both, the data preprocessing pipeline, and the UIDs of 800K curated 3D assets — all under Apache 2.0. The two-stage pipeline does flow-matching geometry generation followed by diffusion-based PBR texture synthesis, with LoRA-based control over symmetry and detail levels.
StepFun's technical report (arXiv 2505.07747) claims geometry and texture quality surpassing existing open-source baselines and comparable to commercial solutions on some metrics — provider-reported, with no independent eval found. An interactive demo runs on Hugging Face Spaces. For researchers and indie game developers who need commercial-grade licensing freedom in 3D generation, Step1X-3D is currently the most permissive serious option.
Specs
Context window
Pricing
Free quota
API access
Weights
Released
Benchmarks
- StepFun-reported: geometry and texture generation quality surpasses existing open-source baselines, comparable to commercial solutions on certain metrics (provider claim, arXiv 2505.07747)
- No independent benchmark table verified
Provider-reported unless a source says otherwise. Benchmarks are marketing-adjacent by nature — treat them as directional.
Use cases
Trust score — 8/10
Scored 8/10 (verified tier, metrics-v1). Evidence: official StepFun GitHub release May 13, 2025 with weights + training code + data pipeline + 800K asset UIDs; Apache 2.0 license confirmed on the HF model card; technical report arXiv 2505.07747; active follow-up releases through June 2025 (texture sync module, watertight preprocessing). Open weights. Strengths: the most completely open serious 3D generator (code, weights, data), permissive license, usable demo. Docked for: (1) quality claims are StepFun's own with no independent evaluation found; (2) smaller community and ecosystem than Hunyuan3D/TRELLIS. License: Apache-2.0.
How the trust score is built
Full methodology →- Adoption · stars/downloads, log-scaled vs peers
- 7.0/10
- Maintenance · recency, releases, issue load
- 8.0/10
- Openness · license + docs
- 10.0/10
- Manual review · sanity read + red-flag check
- 8.0/10
- · StepFun released May 13, 2025: weights (1.3B geometry + 3.5B texture) + training code + data pipeline + 800K asset UIDs
- · Apache 2.0 confirmed on the HF model card (stepfun-ai/Step1X-3D)
- · Technical report arXiv 2505.07747; follow-up releases through Jun 2025 (texture sync, watertight preprocessing)
- · Quality claims are StepFun's own; no independent evaluation found