AI tool comparison
FluidCAD vs Runway
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
Design Tools
FluidCAD
Parametric 3D CAD design using JavaScript code with live viewport
50%
Panel ship
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Community
Free
Entry
FluidCAD is a web-based parametric CAD application that models geometry through JavaScript code instead of mouse-driven GUI operations. Users write code to define extrusions, fillets, boolean operations, and patterns; dragging in the live viewport generates code values that get locked into the script. It supports STEP file import/export with color, a feature history that can be stepped through and rolled back, and VS Code extension support. Gained 149 upvotes on Show HN today, targeting engineers who want code-first CAD with a traditional feature tree.
Design & Creative
Runway
AI video generation and editing for creators
100%
Panel ship
—
Community
Free
Entry
Runway Gen-4 generates video from text and images with unprecedented quality and consistency. Used by Hollywood studios and YouTube creators alike. Features include text-to-video, image-to-video, video-to-video, and motion brush.
Reviewer scorecard
“FluidCAD solves the thing OpenSCAD got wrong: the 'drag to prototype, lock to code' loop makes it accessible without sacrificing programmability. STEP export means it fits into actual hardware workflows, not just rendering. For software engineers doing mechanical work, this is the missing middle ground between Fusion 360's complexity and OpenSCAD's austerity.”
“Code-first CAD has a 30-year history of failing to reach mainstream adoption because engineers and designers don't want to write JavaScript. FluidCAD will appeal to a very narrow slice of software developers who also do mechanical work. The STEP import/export is table stakes, not a differentiator, and Onshape's API does everything this does for teams who need collaboration.”
“Still not perfect — you'll get weird artifacts and the occasional uncanny valley moment. But for 80% of use cases, it's good enough. And 'good enough' keeps getting better.”
“When AI can generate CAD from natural language, the tools that survive will be the ones with programmatic, diffable representations — not binary blob formats. FluidCAD's JavaScript-first approach puts it in exactly the right position for the AI-assisted hardware design wave that's coming. This is the OpenSCAD for the LLM era.”
“Video was the last holdout of 'AI can't do this well enough.' Runway just broke through. The implications for content creation, advertising, and filmmaking are seismic.”
“I appreciate the concept but the UI is clearly built by engineers for engineers. There's no real onboarding, the documentation assumes CAD literacy, and the JavaScript API surface is intimidating for anyone coming from traditional design tools. Until there's a visual-first entry point, this stays a curiosity for most designers.”
“Gen-4 changed my content workflow. B-roll that used to take a day to shoot now takes 30 seconds to generate. The consistency improvements make it actually usable.”
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