Roblox downloaded 145 GB of models from our sites (including adult content) without asking
On 15 and 16 October 2026, a crawler that said it belonged to Roblox walked through almost every project on Open3DLab, SFMLab and SmutBase, and proceeded to download complete copies of 1,027 files from 712 projects. 145.5 GB of our creators' work, downloaded for what we assume are AI training purposes.
This post briefly describes what happened, what mitigations were taken, and what this signals for the community at large. A more detailed writeup outlining what we saw in our logs will be posted at a later time.
What happened
On Sunday the 18th of October, we noticed a crawler making a large number of requests to our sites and download infrastructure. The crawler sent the same user agent on every request, trellis2-data-sourcing/1.0 (3D foundation model research; [redacted]@roblox.com). It came from a single Amazon Web Services (AWS) address. It had read the main page of 18,926 projects, which is practically our entire catalogue, in 26,429 requests over a span of 34 hours.
After pulling the project pages, it downloaded complete copies of 1,027 files from 712 projects, 145.5 GB in all, before suspending operations during the weekend. The downloads include 364 files (54.8 GB) from 224 projects on SmutBase, which hosts adult content only. With the SFMLab projects marked adult, 345 of the 712 projects (62.6 GB) are adult content.
The main limiting factor in the number of files downloaded was the crawler's reliance on the free download servers, which have caps on speed limit and number of concurrent downloads. The crawler did not respect our robots.txt, (which it did retrieve), ignored our Terms of Service, (which forbid scraping), and defied the creators' licenses: 423 of the 712 projects are licensed for non-commercial use only. Within the sample it retrieved, it took adult projects at the same rate as everything else.
Our response
We found it on 18 October and blocked further attempts the same morning. The scraper had suspended its activity by that point, and we did not notice any scraper that weekend. We emailed the address in its user agent on 18 October and asked Roblox for comment. We have not had a reply.
The crawler resumed scraping activity on October 19th, with all requests getting blocked by our servers. The scraper did not reduce its download attempts when faced with our blocks, and the scrapes seemed to fit neatly within office hours, only briefly pausing for an hour around lunchtime, and ending activity around the end of the workday (CEST). On the 20th, their scraper made its final return at 8:00, slowly tapering requests from lunchtime onward, likely in an effort to test our rate limiting. The requests stopped around 15:00. We sent another email to Roblox for questions, to which they again did not reply.
Speculation
Roblox has been building a "3D foundation model" since at least 2025. In March 2025 Roblox introduced Cube, which it calls its core generative AI system for 3D and 4D. The accompanying paper describes the goal as a foundation model for 3D intelligence. It lists character rigging among the things that model should eventually do, and generating characters and avatars as future work. Its first shape model was trained on roughly 1.5 million 3D assets from licensed and public datasets such as Objaverse, plus free assets from Roblox's own Creator Store whose creators had opted in. In February 2026 Roblox began rolling out "4D generation" built on Cube.
The address in the user agent belongs to a researcher who is among the 40-plus authors of that Cube paper. The researcher's public professional profile says they are building a 3D foundation model at Roblox, and their earlier published work is on 3D reconstruction and real-time 3D rendering. We want to be clear: we don't suggest this researcher did anything on their own initiative or out of the ordinary for their job. A data-collection run like this is a company's decision, and the responsibility for it is Roblox's.
The "trellis2" in trellis2-data-sourcing may refer to TRELLIS.2, an open 3D generation model Microsoft released in late 2025. It may mean the data was meant for training or tuning a model like it, or it may just be a project codename. We don't know. What we can say is that TRELLIS.2's published data toolkit contains no web crawler and no user agent, so this crawler and its label were written for the job.
Our sites are full of things a 3D model-generation system needs and public datasets have relatively little of: complete, textured characters, many of them rigged, in the formats artists actually work in, each with a title, a description and preview images.
Put together, we think the most likely explanation is that the crawler was collecting training or evaluation data for Roblox's 3D foundation model work. We can't prove it, and we don't know whether any of our creators' files ended up in a model.
Roblox's track record
This isn't the first time Roblox has been criticised for how it treats the people whose work its platform runs on, or for how it handles other people's rights. None of this proves anything about the crawler, but it strengthens our opinion that Roblox is a deeply unethical business. It shows a company that has repeatedly been accused of putting growth ahead of the people its platform depends on.
You see how this looks, right?
More than a third of Roblox's daily users were under 13 in 2025, by its own figures. Its rules ban sexual content, and in 2025 it tightened them further.
Roblox's crawler took 224 projects from a site called SmutBase, which describes itself as exclusively for adult content, and 121 more that are marked adult on SFMLab. It took them at the same rate as everything else: 345 of the 712 projects it downloaded from are adult content. The further scraping attempts did not discriminate between adult content either.
We want to be careful here. We don't think Roblox set out to collect adult content, and we have no evidence that any of it reached a model or a product. The scrapes were likely automated. But that is exactly the problem: as far as our logs show, nobody checked. A crawler working for a company whose platform tens of millions of children use was pointed at an adult site, and it took explicit models without telling them apart from anything else.
If the penalty for a crime is a fine, then that law only exists for the lower class.
Roblox isn't the worst offender in AI's appetite for other people's work, just the latest to turn up in our logs. It isn't the only AI company in them, either. In the month before we found trellis2-data-sourcing, Meta's AI crawler, Meta-ExternalAgent, made about 380,000 requests to our sites, almost all from Meta's own network, and loaded 211,000 project pages. We have since blocked their crawler as well.
The Roblox trellis2 crawler is the first individual crawler we spotted that actually pulled assets uploaded by our users, in flagrant defiance of any copyright or license that might apply to it. It fits a broader context, of AI labs taking content without permission.
We're pointing out that the copyright we have isn't applied equally, and is in practice a two tier system. Individuals face ruinous damages for minor infractions. The largest companies in the world face a cost to be negotiated after the fact, if anyone can afford to sue them. A law that only works downwards gives nobody a reason to respect it, and it can't last in this form.
Questions for Roblox
We're sad that the emails we sent to Roblox were not met with a timely response, and would thus like to publicly ask Roblox for its response. These are the questions we'd like Roblox to answer:
- Did Roblox run the
trellis2-data-sourcingcrawler? - What was the data for? Has any of it been used to train or evaluate a model, and if so, which?
- Why did the crawler ignore our robots.txt rules and our Terms of Service?
- Did anyone review which sites the crawler would visit? Was adult content excluded at any stage?
- Will Roblox delete the files and anything derived from them, and confirm that in writing?
- Will Roblox respect our creators' license choices, NonCommercial in particular, from now on?
