➤ This week's Crossing guest is Juanjuan, born Ren Lifeng, founder and CEO of Hitems. He previously led the team that incubated Douyin and shepherded it from 0 to 1, and is widely considered one of the key driving forces behind its rise.
This is a nearly three-hour conversation: we started with how Douyin was originally greenlit, moved to Hitems' newly released Hi3D 3.0 2048³ model, and discussed their ambition to evolve from Maker OS toward a "manufacturing OS."
After talking with Juanjuan, my strongest impression was: foundation models won't swallow everything.
Large language models and multimodal models may appear capable of generating anything, but once you enter physical manufacturing, you still need models that can produce "production-grade" 3D assets. And the real difficulty usually comes after the model: how to break parts down, how to add connection structures, how to adapt to different materials and equipment; how to unfold plush curved surfaces into paper patterns, how to convert images into stitch patterns that embroidery machines can read; and how, amid high-volume orders where every piece is different, to deliver products to customers on time.
This explains why Hitems has extended from 3D large models all the way to tools, factories, transactions, and ecosystem — and why they're pushing their target from Maker OS toward manufacturing OS. What they're building is a production pipeline that channels ordinary people's creative impulses into the physical world.
This is a long conversation about AI, trends, products, ambition, and spiritual practice — and the story of someone who built a super product, now becoming a startup novice all over again.
🎬 Our video podcast will be available simultaneously on Koji's WeChat Channels, Douyin, Xiaohongshu, Bilibili, YouTube, and other platforms.
📒 The transcript will be published on the CrossingCrossing WeChat official account.
00:25 Rapid-fire Q&A: age, MBTI, zodiac sign, one-line introduction, funding status, team size, pre-entrepreneurship experience
02:33 How did Douyin originally spot its opportunity through internet speed, mobile hardware, and signals from Kuaishou and Musical.ly?
09:29 How did early Douyin both inspire and make ordinary users feel seen?
12:04 Both Douyin and AI 3D were big opportunities identified through key industry variables
19:05 Why did Juanjuan pivot from content products to AI 3D and manufacturing?
23:43 When factories only care about orders, revenue, and profit, why was Hitems forced to build its own experimental factory in Panyu?
26:26 What conflicts arise between the growth hunger of internet products and the cycles and commercial laws that manufacturing must respect?
28:12 Did you leave ByteDance to start a company because you were dissatisfied with yourself?
36:05 The first thing you did after deciding to start a company
41:34 Compared to older versions and competitors, why can the Hi3D 3.0 model reconstruct text and complex symbols at the geometric level?
49:33 Did Hi3D 3.0's leap come from more high-quality data, a technical approach change, or post-processing algorithms?
55:16 From a single image to direct printing: how does Hi3D automatically complete part breakdown, connectors, nesting, and parameter settings?
01:00:06 As video models like Seedance 2.5 grow stronger, do games and film still need AI-generated 3D?
01:01:53 3D is the hardest modality for which to acquire data — how does Hitems obtain training data from industrial belts?
01:06:31 The female Maker market is growing rapidly
01:15:44 Where does Goodthings' over 20% submission rate come from, and why does receiving the physical product rekindle creation?
01:19:16 "Production-grade direct output," T+7 on-time delivery rate, offline evaluation lab
01:28:12 Will 3D printing hit a ceiling, and how will desktop CNC, laser, and flexible equipment expand the Maker market?
01:32:47 From 300 to 30,000-unit 3D printing farms: why are they still trapped in homogenization and creator revenue problems?
01:39:19 Which lessons from Douyin's 0-to-1 journey are reusable, and which will fail in an AI 3D startup?
01:54:40 Will there be another Douyin in the AI era?
01:58:49 How does entrepreneurship become spiritual practice?
02:02:03 Advising some people "don't start a company if you don't have to," while supporting others in doing so
02:05:12 The definition of success
02:10:18 "I am fundamentally an insecure person"
02:16:42 From "nice guy" to responsible CEO
02:22:51 Good luck
Subscribe to Crossing: 🚦 We track the industry transformations and new entrepreneurial opportunities brought by the new wave of AI technology.
🚦 "Crossing" is Steve Jobs' metaphor for Apple — standing at the intersection of technology and liberal arts, where great products are born. AI is transforming every industry. We seek out, interview, and bring together a new generation of AI entrepreneurs and active builders in the AI era, exploring and embracing new changes and new possibilities alongside them.
👦🏻 Host Koji: I founded Crossing, launched AI Hacker House — a community space for the new generation of AI entrepreneurs — and serve as Venture Partner at ZhenFund. I believe technology, especially AI, represents the greatest value creation opportunity of our generation. Koji on Jike, Koji's website
View episode transcript on Xiaoyuzhou