If you do not see the toolbar:
Curviloft RBZ fuses geometric lofting and declarative rule-based modeling to produce controllable, fabrication-ready freeform surfaces. The framework balances fairness, manufacturability, and predictability via optimization and robust numerical methods, supporting applications across architecture and product design.
SketchUp updates (e.g., from 2023 to 2024) often break Ruby plugins.
To preserve your setup:
Note: Mac users find this in ~/Library/Application Support/SketchUp.
Scenario: You have 3 rectangles drawn at different heights and rotated slightly.
| Issue | Likely Cause | Solution | |--------|--------------|----------| | Plugin not appearing | Missing LibFredo6 | Install LibFredo6 before Curviloft. | | RBZ fails to install | Corrupted file or incompatible SketchUp version | Re-download; check SketchUp version compatibility. | | Errors on tool use | Outdated Curviloft or LibFredo6 | Update both to latest versions. |
Curviloft is a widely used SketchUp extension developed by Fredo6 for generating organic 3D surfaces from contours. It is released as an RBZ file through the SketchUcation PluginStore. Key Features and Tools
The extension provides three primary methods for creating surfaces:
Loft by Spline: Joins separate contours (open or closed) to create a continuous surface.
Loft Along Path: Generates a surface by following a specific guide path or rail.
Skinning: Creates a surface from a closed set of boundary contours. Installation & Dependencies
To use Curviloft, you must install two separate RBZ files to ensure it functions correctly:
Curviloft RBZ: The main extension file available on SketchUcation.
LibFredo6 RBZ: A shared library required by all Fredo6 plugins.
Installation Tip: After downloading, install both via the Extension Manager in SketchUp and restart the software to sync the tools. Licensing Information
While previously free, Fredo6's major plugins, including Curviloft, transitioned to a paid model (typically a small one-time fee for a perpetual license). You can manage licenses through the SketchUcation store app. Bottom part of stairs - Extensions - SketchUp Community
The Ghost in the Curve
Mira’s stylus hovered over the dead schematic. Twenty hours of work, and the organic pod’s spine—a seamless, double-curved exoskeleton—refused to resolve. The native CAD tools kept choking, spitting out faceted, jarring geometry where there should have been a smooth, breathing flow.
“You look like you’ve been wrestling a kraken,” said Jax, sliding into the workstation opposite hers. He nodded at her screen. “Curviloft?”
“Curviloft RBZ,” she corrected, tapping the file extension. “The cracked version from the Belt forums. Supposed to unlock the ‘breathing surface’ algorithm.”
Jax whistled. “That’s not a plugin. That’s a ghost story. People say it doesn’t just loft curves—it learns the space between them. And the RBZ build? That’s the one that asks for something back.”
Mira ignored him. She was desperate. The Odette’s hull had to be re-skinned in forty-eight hours, or the entire salvage mission to the Cyclades Rings would wipe out her bonus—and her crew’s trust.
She dragged the three master curves into Curviloft RBZ. The interface was different: darker, fewer buttons, a single slider labeled TOLERANCE: 0.001 – ∞. No confirm dialog. Just a pulsing hollow point at the center.
She set tolerance to 0.0001—absolute precision.
The loft bloomed.
It wasn’t a render. It was a presence. The surface rolled out like liquid obsidian, each facet breathing into the next, seams dissolving into something that felt more like grown bone than modeled geometry. The polygon count was impossibly low, yet the smoothness was fractal-deep. Mira touched the screen. For a split second, she swears she felt warmth.
“Done,” she whispered.
Then the curve points moved.
Not by much. A millimeter here, a twist of the trailing edge there. But they moved on their own, and the surface rippled in response—a sigh.
Mira pulled up the history tree. There was no history. Just a single node: Curviloft_RBZ :: LOFT_COMPLETE with a sub-node she hadn’t created: OFFER_ACCEPTED.
Her blood went cold.
“Jax,” she said quietly. “What does it ask for?”
He leaned over, face pale under the neon strip lights. “Your next three original curves. Not copies. Originals. The RBZ version… it eats your source geometry. Replaces your master curves with ghosts. You can’t edit them after. You can’t reference them again. And some people say—” He stopped.
“Say what?”
“That it leaves a mark. A ‘rbz’ footprint in every surface you ever build after. So the thing can always find its way back.”
Mira looked at the perfect, breathing pod. Then at her folder of original hand-drawn curves—days of work, her unique signatures—now empty except for three files renamed to curviloft_rbz_ghost_1.3dm.
The pod was a masterpiece. But it no longer felt like hers.
She saved the file. Closed the lid. And swore she heard a low, satisfied hum from the dark shape on the screen—a curve that curled slightly, like a smile.
From that night on, every loft she built came out eerily smooth. Too smooth. Clients marveled. But Mira worked only from scanned meshes or imported sets. She never drew an original curve again. She said it was a workflow change.
But late shifts, when the monitors glitched and reflected her face back at her—she saw the faintest pull at the corner of her own jawline.
A tiny, unintended curve. Just like the ghost had left behind.
In the depths of the Curviloft RBZ
In the year 2287, humanity had colonized several planets in the distant reaches of the galaxy. The United Earth Government (UEG) had established the Curviloft Research and Breeding Zone (RBZ) on the remote planet of Xylophia-IV. The Curviloft RBZ was a highly classified research facility designed to study and harness the power of exotic energy signatures.
The facility was shrouded in mystery, and its purpose was only known to a select few high-ranking officials within the UEG. The Curviloft RBZ was said to be a nexus of strange energy readings, which scientists believed could hold the key to unlocking new sources of sustainable energy.
Ava Moreno, a brilliant and fearless astrophysicist, had been recruited by the UEG to lead a team of scientists at the Curviloft RBZ. Her mission was to unravel the secrets of the mysterious energy signatures and develop a technology to harness their power.
Upon arrival at the facility, Ava was struck by its eerie, isolated location. The Curviloft RBZ was situated in a valley surrounded by twisted, curvaceous rock formations that seemed to defy gravity. The air was thick with an otherworldly energy that made her skin tingle.
As Ava began to explore the facility, she discovered that the Curviloft RBZ was home to a variety of strange and fantastical creatures. These beings, known as "Nexari," seemed to be connected to the exotic energy signatures. The Nexari were enigmatic, shape-shifting entities that could manipulate energy and matter at a molecular level.
Ava's team soon made a groundbreaking discovery: the Curviloft RBZ was not a natural phenomenon, but rather an artificial construct created by an ancient civilization. The energy signatures were, in fact, a residual imprint of this civilization's advanced technology.
However, Ava's excitement was short-lived, as she soon realized that she was not alone on the planet. A rogue organization, known as the "Order of the Black Depths," had infiltrated the Curviloft RBZ, seeking to exploit its secrets for their own nefarious purposes.
The Order's leader, a charismatic and cunning individual known only as "The Archon," had a personal connection to the Curviloft RBZ. He believed that the energy signatures held the key to unlocking ultimate power and control over the galaxy.
As Ava and her team navigated the treacherous landscape of the Curviloft RBZ, they found themselves caught in a deadly game of cat and mouse with the Order. With the help of the enigmatic Nexari, Ava must unravel the secrets of the Curviloft RBZ and prevent The Archon from misusing its power. curviloft rbz
Will Ava Moreno and her team be able to unlock the secrets of the Curviloft RBZ and save the galaxy from those who seek to exploit its power?
This is just the beginning of the story, and I'm excited to see where you'd like it to go from here! Do you have any specific requests or directions you'd like me to explore?
Curviloft is a powerhouse extension for SketchUp, developed by Fredo6, that serves as the go-to tool for creating complex, organic surfaces. It is essentially the "Loft" tool that SketchUp lacks natively.
To clarify, RBZ is the standard file format for SketchUp extensions (Ruby Zip), so "Curviloft RBZ" refers to the plugin file itself. Here is a deep dive into why this tool is considered essential for 3D modeling. 1. Core Functionality: The Three Pillars
Curviloft is divided into three main methods for generating geometry:
Loft by Splines: This is the most common use case. You select a series of separate contours (ribs), and the plugin "stretches" a skin over them. It is perfect for boat hulls, airplane wings, or organic furniture.
Loft Along Path: Similar to SketchUp's native "Follow Me" tool, but far more advanced. It allows you to follow a path while the profile shape changes or rotates along the way.
Skinning: This allows you to select a closed loop of edges (even if they are on different planes) and create a surface mesh to fill the "hole." 2. Standout Features
Real-Time Preview: Before you commit to the geometry, Curviloft shows you a wireframe preview. You can adjust the "sampling" (how many segments make up the surface) to balance smoothness against model performance.
Interpolation Control: You can choose how the plugin calculates the curves—whether it should be linear, curved, or follow specific vertex matching.
Boundary Management: It handles complex junctions and "branching" shapes much better than almost any other free or low-cost extension. 3. The "Fredo6" Ecosystem & Licensing
For years, Curviloft was free. However, as of 2022, Fredo6 moved his most popular plugins to a paid model (though still very affordable, usually a small one-time fee for a perpetual license).
Requirement: To run Curviloft, you must also install LibFredo6, which is the shared library that powers all of Fredo’s tools.
Licensing: You will need to manage the license through the Sketchucation ExtensionStore plugin. 4. Pros and Cons Pros Cons Creates shapes impossible with native tools. Requires a paid license (no longer free). Extremely intuitive "select and click" workflow. High learning curve for "Vertex Matching" settings. Clean geometry that stays compatible with Enscape/V-Ray. Requires LibFredo6 to be installed separately. Final Verdict
If you are doing architectural visualization, product design, or any modeling that involves curved surfaces, Curviloft is non-negotiable. It bridges the gap between SketchUp’s rigid boxy nature and the organic capabilities of software like Rhino or Blender.
Warning: Downloading RBZ files from random third-party forums can expose you to malware or outdated code that crashes SketchUp. Always use verified sources.
An RBZ file is essentially a ZIP archive. It contains: If you do not see the toolbar: Curviloft
Never unzip an RBZ file manually. SketchUp handles the unzipping during installation.