A real-time GPU engine
Physically based materials, soft shadows, ambient occlusion, image-based lighting, glass, water and fire, drawn as you work, on OpenGL or Vulkan.
Everything you dreamed of. And then some.
Thundereal is FreeCAD rebuilt where it counts: a renderer that brings your design to life while you are still building it, a geometry kernel that finishes the shells, fillets and drafts others give up on, and a model that remembers every step and branches like code.
- Open source, LGPL-2.1+
- Opens FreeCAD files
- Linux, Windows, macOS
- Browser and mobile, through sharing
The renders from the tutorials, made right here
The glossy product shots in YouTube CAD tutorials usually take a trip through another program. In Thundereal you make them in the window you model in, from the same materials, and they stay live while you edit.
Screenshot pending: A product model rendered live in the 3D view
Screenshot pending: Threads and knurls up close
Screenshot pending: The same model in Cycles
Surface finish
Screw threads that look cut, not painted: a tapped hole or a bolt's shank shows its helix at its true pitch and profile. Knurled, brushed, blasted and turned too, face by face, with no UV mapping to set up.
MaterialX
The industry's open material standard, with a node-graph editor to build your own shaders and keep them on a material card.
Cycles
Blender's path tracer runs inside the 3D view for the final, photoreal picture. Your materials and finishes carry over.
A kernel that finishes the job
Thundereal ships its own fork of OpenCASCADE, the geometry kernel under FreeCAD, fixed case by case against models from real bug reports and checked against upstream on every fix.
Screenshot pending: A shell and a corner blend, upstream beside Thundereal
Screenshot pending: The new draft on a filleted part
Thickness
Shells that fail or come out inside out upstream now come out right: past concave corners, beside tangent faces, over domes, with a fillet removed, with either join.
Fillet
Corner blending: where fillets meet at a vertex, a setback blend instead of a pinched corner, and a smooth patch where the corner can't be solved exactly. Fillets on edges short for their radius are retried, not refused.
Draft
A new draft that can change topology. Walls and the fillets between them draft as one sheet, fillets turn into cones, and past an apex the walls meet in a ridge. Auto takes it wherever the classic draft would cross itself.
A model with a memory
FreeCAD keeps an undo stack that is gone when you close the file. Thundereal writes every step into the document's transaction log, and builds on it what git gives code: versions, branches, merge and diff.
Screenshot pending: The transaction log panel: a branch, and a merge's preview in the 3D view
Every step, kept
Each edit, undo, recompute and save is a row, with every value before and after. The log travels inside the file: open it next month and the history is still there.
Versions
The whole document as it was at a moment, to look at, open or go back to. Undo one step that isn't the last.
Branches
Try the risky idea on a branch while the main design stays as it is, on the same file.
Merge
Changes merge by what they touch: a face painted on one branch and a fillet added on the other both survive, and a sketch merges by what it holds.
Shape diff
See what a merge, a version or a single step would change, drawn as shapes in the 3D view, before you take it.
Requests
Someone sends you their changes. You look them over and take what you want.
And then some
The big things and the small ones that make the day go faster.
Screenshot pending: A shared model open on a phone beside the desktop
Large models
Documents load progressively and stay usable while they load. Links place one part in many places without copying it.
Share it live
Send a link and the model opens in a browser, on a phone too. A sign-in door decides who gets in.
Split views
Tile the window like Blender: a 3D view beside a drawing page, each showing what you choose.
Press /
One search box for objects, commands and every setting.
Safe files
Formulas in a file you were sent run in a sandbox, and so do the Python features stored in it.
Bring your AI assistant
A built-in MCP server lets an AI assistant read the model and drive the program.
Side by side with FreeCAD
Where the two differ today: what is built and measured, not what is planned.
| Item | Feature | FreeCAD | Thundereal |
|---|---|---|---|
| 20 | 3D view | Coin3D on fixed-function OpenGL | PBR GPU engine on OpenGL or Vulkan, with surface finishes |
| 21 | Threads | A PNG texture over the bore | A real helix at the thread's pitch and profile, on any turned face |
| 22 | Photoreal | An add-on and an external renderer | Cycles inside the 3D view, MaterialX materials |
| 23 | Thickness | Upstream OCCT: 123 to 132 of 204 sweep runs right | 204 of 204 |
| 24 | Fillet corners | Pinched or refused where fillets meet | Setback corner blends, with a smooth fallback patch |
| 25 | Draft | Fails where the drafted walls would cross | A draft that may change topology, chosen automatically |
| 26 | History | An undo stack, gone when the file closes | Every step kept in the file, with versions, branches, merge and shape diff |
| 27 | Reviewers | Need FreeCAD installed | Open a live link in any browser |
| 28 | Files | .FCStd | .FCStd, both ways, and the compact .TStd |
Built on FreeCAD
Thundereal is a fork of FreeCAD, and wouldn't be possible without the FreeCAD community. It keeps FreeCAD's Python API, so macros and most add-ons work unchanged.
It grew out of the Link branch, where App::Link and the first fix for topological naming started, and it is free software under the same license, the LGPL 2.1 or later.
Thundereal is not FreeCAD. Please report its bugs on Thundereal's tracker, not upstream's.
Support the work
Thundereal is made in the open. If it saves you time, these keep it going.