This update brings more than just polish—it’s the foundation for a faster, more fluid design experience, built around the way Copilot is used today and the way we see it evolving tomorrow.
This guide is here to help. Based on the most common questions we hear from our users, it walks through practical solutions to unblock your designs and give you more confidence as you build.
Flux is built to help you move fast—from idea to fully routed board—with powerful automation, AI-assisted design, and intuitive tools that make professional workflows accessible to everyone. But even the best tools come with a learning curve, and occasionally you might run into something unexpected.
This guide is here to help. Based on the most common questions we hear from our users, it walks through practical solutions to unblock your designs and give you more confidence as you build.
Whether you’re new to PCB design or just new to Flux, these tips are designed to save you time and help you get the most out of the platform.
“Why am I seeing DRCs for overlapping copper?”
Overlapping copper errors typically occur when copper from two different nets occupies the same area on a PCB layer. This can lead to short circuits, unexpected connections, and compromised board performance. Flux flags these cases as design rule violations to protect the electrical integrity of your design.
Tip💡: Enable all layers in your visibility settings. Overlaps sometimes occur between nets on different layers and can be easy to miss.
“Why is Flux saying I have conflicting fills?”
Flux automatically adds GND fills to each layer, but if more than one net is assigned a fill on the same layer, it creates a conflict. The system prevents this to ensure clean and predictable copper behavior.
Only one net should apply fills per layer—typically GND, unless you're working on advanced designs requiring power planes or split fills.
“What is floating copper, and why is it an error?”
Floating copper refers to any copper (usually a fill or trace) that is no longer electrically connected to its assigned net. This often happens when components are moved or deleted, leaving behind orphaned copper.
Keeping copper grounded and connected ensures electrical correctness and helps avoid manufacturing issues down the line.
“My board has no visible GND fills—what’s wrong?”
By default, Flux adds ground fills to all PCB layers for the GND net. If you’re not seeing them, it’s usually a configuration or visibility issue rather than a bug.
Fills play a crucial role in EMI reduction, return path continuity, and thermal performance, so it's important to verify they're in place.
“I created a part, but I can’t find it in my library—where is it?”
When you create a custom part in Flux, it lives in a separate project until you publish it. Publishing is what makes it available in your global or team library.
🔒 By default, newly created parts are private.
If you want others to use it, click “Share” and set visibility permissions. Just remember to re-publish after updating sharing settings.
“I imported my Altium file, but nothing shows up.”
This usually comes down to format. Flux only supports ASCII format when importing from Altium Designer. If you export in binary format, the import will silently fail or appear blank.
To verify: open the file in a text editor. If it’s human-readable, it’s ASCII. If it’s gibberish, it’s binary.
Large schematics? Try breaking them into modules for smoother imports.
“Why is Auto-Layout stuck on ‘Optimizing’?”
Flux’s Auto-Layout feature can take time—especially on complex boards. The “Working” state may appear stuck if DRCs are unresolved, or if the board has high routing complexity.
If needed, hit Stop to investigate and restart. Just be aware that stopping clears progress if changes haven’t been applied.
“I imported a KiCAD part—why is it incomplete?”
Flux supports KiCAD library imports, but some metadata—like footprints or 3D models—need to be linked manually.
Once set, the part will behave like any other in your library.
“Why is Copilot making strange connections?”
Flux Copilot is optimized for specific, context-aware actions. It’s not intended to auto-wire an entire schematic in one go, and complex instructions often reduce its accuracy.
With more focused prompts, Copilot becomes a powerful assistant rather than a source of confusion.
“Where can I go when I need support fast?”
We want you to feel confident using Flux, even when things aren’t going smoothly. Here's how to get help:
Building with Flux means working with one of the most forward-moving platforms in EDA—but we also know that speed comes with bumps along the way. This guide is here to help you smooth them out and keep shipping.
Most importantly, you’re not alone. Whether it’s a UI quirk, a Copilot misfire, or just needing a second pair of eyes, we’re here to help—through docs, videos, chat, or Slack.
And if something isn’t working the way you expect, let us know. The fastest way we improve Flux is with your feedback.
We're excited to unveil our Smart Polygon system in Flux! This powerful capability builds on top of our automatic copper fills to transform how you create and manage custom copper areas in your PCB designs.
Smart Polygons in Flux behave intuitively like traces, making them straightforward to learn and use—start directly from any pad with automatic net association, simply click to place and adjust points, and watch as copper intelligently reflows in real-time. Let’s dive in!
In PCB design, polygons are customizable copper shapes directly tied to a specific net. They’re crucial because they significantly influence the electrical performance and reliability of your PCB. Polygons allow you to optimize your board layout for specific electrical properties, including improved grounding, controlled impedance, and efficient heat distribution.
Specifically, polygons are indispensable for:
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Unlike zones—which define areas where copper cannot exist—polygons actively conduct electricity and shape your board's electrical performance, making them fundamental for advanced PCB designs.
At Flux, we prioritize intuitive, user-friendly workflows. Automatic copper fills were the first step. Now with polygons, we've continued this approach:
Polygons in Flux behave intuitively like traces, making them straightforward to learn and use, right from the start.
Polygons in Flux pack powerful functionality without complexity:
Polygons unlock new possibilities in your PCB designs. Here are a few practical ways you'll benefit:
Whether you're just dipping your toes into PCB design or you’re a veteran engineer tackling complex layouts, polygons in Flux offer the ideal balance of simplicity and capability:
Polygons are available now in Flux, ready to enhance your PCB design capabilities. Explore this powerful feature today and experience firsthand how advanced design can truly be this easy.
Dive in now and check out our detailed polygon documentation or jump straight into Flux to try it yourself. We can't wait to hear what you think!
In this post, we’ll explore why these concepts matter, how they impact signal integrity and power distribution, and what to keep in mind as you design. If you want to go deeper into implementation details—like when to use zones, where to place stitching vias, or how to avoid stack-up pitfalls—we’ve created a detailed PDF guide just for that.
That’s where ground planes, zones, and stackup symmetry come in. They’re the quiet guardians of signal integrity, and Flux is built to help you get them right—without the guesswork.
In this post, we’ll explore why these concepts matter, how they impact signal integrity and power distribution, and what to keep in mind as you design. If you want to go deeper into implementation details—like when to use zones, where to place stitching vias, or how to avoid stackup pitfalls—we’ve created a detailed PDF guide just for that.
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Every signal you route is part of a circuit. And that circuit includes the return path—the signal that flows back to the source. At high speeds, this return doesn't just wander through your board—it seeks the lowest impedance path back.
That path is normally the ground plane directly beneath the signal layer. If the plane is continuous, the return path stays tight, inductance stays low, and EMI stays minimal.
But if the ground is broken—say, by a split—the return path will form a bigger loop. And bigger loops might mean bigger problems: signal distortion and radiated emissions that could cause a failed EMI test.
Good return paths are invisible when they work, and painfully visible when they don’t.
You’ve probably heard the advice: “Split your ground plane between analog and digital.” Sometimes that’s sound engineering. But often, it leads to more trouble than it solves.
The key question isn’t “Should I split my ground plane?”—it’s “Will this split create more noise than it prevents?”
In most cases, you should avoid splitting the ground plane. Here's why:
A PCB stackup isn’t just a layer count—it’s a design decision that affects everything from signal integrity to manufacturing yield.
When your layout starts pushing higher speeds or tighter constraints, your stackup becomes critical. It defines the electrical environment for your signals and the mechanical stability of your board.
For most standard boards—say, 4 to 6 layers on 1.6 mm FR4—mechanical issues like warpage are rarely a showstopper with modern fabrication processes. Today’s board houses are well-equipped to handle these with balanced copper and proper lamination.
But in more demanding cases, stack symmetry still matters:
The rule of thumb: the more complex or thermally sensitive your board, the more stack symmetry and copper balance matter. It’s not just about layout—it’s about ensuring the board survives fab, assembly, and real-world use.
If you remember nothing else, start with these rules:
We’ve built these rules into Flux—not as rigid constraints, but as default guardrails. So you can break them when needed—but only when you know you need to.
High-speed, low-noise boards don’t happen by accident. They’re designed intentionally—from the copper up. Whether you're debugging EMI issues or laying out a complex mixed-signal board, your ground strategy is the foundation.
With Flux, you don’t need to memorize every trick in the book. We’ve integrated the most important ones into your workflow—so you can focus on building, not second-guessing.
Ready to ground your designs the right way?→ Open Flux and give your next project the return path it deserves.→ Or dive deeper into Zones and Cutouts » | Stackup Editor »
Whether you’re routing high-speed buses, fine-tuning antennas, or laying out clean RF filters, sharp 90º or even 45º angles can be a serious bottleneck. Now, you can create precisely curved elbows across entire nets—or dial them in trace by trace—with full control over radius, inheritance, and overrides.
We’re excited to announce one of the most requested features from advanced users: Curved Traces are now available in Flux!
Whether you’re routing high-speed buses, fine-tuning antennas, or laying out clean RF filters, sharp 90º or even 45º angles can be a serious bottleneck. Now, you can create precisely curved elbows across entire nets—or dial them in trace by trace—with full control over radius, inheritance, and overrides. Curved Traces were built to work the way you already do in Flux. You don’t need to micromanage every elbow—just set your rules once, and let the system handle the rest.
Need to override an elbow? You can. Want to apply curved traces to an entire layout? Go for it. You’re in the driver’s seat, and the system has your back with smart defaults, inheritance, and DRCs that surface only when needed.
This release sets the stage for what’s next: full support for flex and rigid-flex boards. Curved Traces are the first major unlock—and we’re actively building the rest. Flex is on the way.
This isn't just about cosmetics. Curved traces improve routing quality, unlock new design styles, and remove a major blocker for:
Until now, you had to work around Flux’s sharp elbows. Now, you can design the way the pros do—with full control over every bend.
Curved Traces give you a new level of control over how your signals move across the board—whether you’re designing critical paths or polishing the final layout. To use curved traces:
1. Enable curved routing - Set the Trace Shape rule to "Curve" at the layout, net, or individual segment level. This tells Flux to apply curves instead of sharp elbows wherever possible.
2. Set a minimum radius - Use the Trace Corner Radius Minimum rule to define the smallest allowable curve. This helps ensure manufacturability—especially for tight layouts or impedance-sensitive routes.
3. Leverage inheritance - Apply your rules at the layout or zone level so they cascade automatically. You can mark rules as !important to make them stick when conflicts arise.
4. Override specific elbows - Need more control? Just click and drag the trace elbow or use Trace Corner Radius Start/End or Trace Shape Start/End to adjust a specific corner without affecting the whole trace.
5. Watch for DRC warnings - Flux will flag any elbows that can’t meet your minimum radius—so you can adjust your layout before it becomes a real problem.
6. Mix manual + auto-routing - Route critical traces by hand to maintain control—then auto-route the rest. Flux will respect your curved segments and finish the job cleanly.
If you’ve ever spent time nudging elbows, adjusting angles, or finessing a meander by hand, this is the update you’ve been waiting for.
Want to see what’s possible? We’ve put together a few fully forkable example projects that showcase curved trace routing in the wild:
Open them, explore the layout rules, and make them your own.
Curved Traces are a foundational feature—especially for advanced workflows. But they’re also a signal: we’re investing deeply in professional-grade capabilities, from stackups and automatic impedance control to AI auto-layout and AI-assisted design reviews. If Flux wasn’t quite enough for your pro projects before, now’s the time to jump back in.
Curved Traces are available to all users starting today. Just open any project, apply the "Curve" trace shape in your layout rules, and start routing. It's that simple.
Got feedback or something cool to share? Post in the Flux community or tag us—we’d love to feature your work.
Let’s bend some traces.
👉 Open Flux and try it now.
With the latest release of Copilot it isn’t just smarter—it’s hands-on, placing components and applying bulk changes to your project instantly. But to get the most out of it, knowing how to craft the right prompt is key.
Copilot won’t generate an entire schematic from scratch or handle a full workflow in one go—yet. Instead, it works best when guiding you step by step. The more details you add—like project goals, placed components, or design constraints—the more context Copilot has to carry across conversations, making its recommendations more relevant and accurate.
We've updated our list of top prompts based on what users find most effective, helping you streamline everything from brainstorming and component research to BOM management and design validation. Here’s how to get the best results from Copilot—and a collection of powerful prompts to speed up your workflow.
Spread the word and share your favorite prompts on our Slack Community. Below, we’ve grouped some favorite prompts by category. Each section starts with extra tips to help you get the most out of that set of commands.
Imagine an AI teammate that doesn’t just chat about your PCB ideas, but actively transforms them into schematics—placing parts, connecting circuits, and optimizing your design at your command, all through natural language. That’s exactly what the newly overhauled Flux Copilot does.
Ever since we launched Copilot, our goal has been to create a truly collaborative design partner—one that goes beyond offering advice to actually executing on your behalf. Today, we’re thrilled to unveil the next major leap in that journey!
Copilot is now powered by more advanced reasoning models and has the full context of your project—datasheets and your custom design rules—enabling far faster, and more accurate recommendations than any standalone AI chatbot could offer. Best of all, you remain in control, free to accept or refine any of its actions as you progress.
This isn’t just an upgrade—it’s a whole new way to design hardware with AI. Let’s dive in!
Starting a new hardware project can feel overwhelming. Even if you know exactly what you want to build, transforming your idea into a functional schematic requires choosing components, verifying specs, and ensuring each piece fits together seamlessly.
The completely overhauled Copilot takes the guesswork out of this process by engaging you in a focused conversation about your project. Instead of juggling datasheets and sourcing websites, you simply outline your goals—like “I want to build a battery-powered sensor module with an ESP32”—and Copilot follows up with questions to refine your requirements as a seasoned hardware engineer would.
Copilot: "Sounds great! Which sensors would you like to use—temperature, humidity, or something else?"
Once your specs are clear, it compiles a Bill of Materials (BoM) in seconds, giving you a curated list of compatible, optimized parts. You can review and adjust any element of the BoM before moving forward, confident that you’re building on a rock-solid foundation—without wasting hours on manual research.
After finalizing your BoM, Copilot can take the next step by placing each component into your schematic—whether it’s a microcontroller, sensor, or power module. It searches the library and drops parts onto your canvas in a way that avoids overlap, so you’re not starting from scratch.
With your key components in place, the next step is fine-tuning the design—often starting with decoupling capacitors. Traditionally, you’d consult datasheets for recommended values and place each capacitor manually. Copilot streamlines all of that into a single prompt:
You: "List all the decoupling capacitors that are needed for this design."
Copilot: "Below is a recommended list of decoupling capacitors for your sensor module design. Would you like me to add them to your schematic?"
Copilot identifies which parts need decoupling, calculates the optimal values, and places the capacitors next to their relevant pins. This alone can save you hours of research and tedious work, letting you maintain focus on the bigger picture.
Once your parts are positioned, the next challenge is ensuring everything is correctly wired—pin assignments, best practices, net labeling, and so forth. With Copilot, wiring becomes as straightforward as telling it which components to connect:
You: "Can you connect @U1 to @U3?"
Normally, this would mean double-checking pinouts, referencing datasheets, and verifying each signal. Copilot handles those checks behind the scenes, making the required connections in seconds. You can still review and adjust as needed, but the bulk of the manual labor is eliminated.
Even if your schematic is fully functional, there’s often room for optimization—maybe you need a sensor with higher resolution or a regulator that handles more current. Instead of searching for alternatives on your own, let Copilot do the legwork:
You: "Find a better alternative for U1 in the @library that has a higher resolution."
Copilot scans for a suitable match, checks it against your existing circuit constraints, and offers a drop-in replacement. Once confirmed, it updates your schematic accordingly—no library lookups needed.
While Copilot automatically picks the best tools and models for most tasks, sometimes you need a little extra control. Whether you’re pulling equations from a datasheet, sourcing components from the Flux library, or performing quick calculations, prepending an "@" symbol tells Copilot exactly which tool or model to use—so you can fine-tune your workflow.
You can also choose from multiple AI models, each suited to a specific task:
This flexibility ensures you’re always getting the right balance of speed and detail.
This release marks a pivotal step toward the future of AI-assisted engineering. Flux Copilot isn’t just here to answer questions—it’s evolving into a genuine design partner, one that helps you move faster, reduces friction, and keeps you focused on real engineering challenges. But we’re only scratching the surface of what’s possible.
Our larger vision is to automate even more of the tedious steps in hardware design—like routing and board layout. If you haven’t already, check out our AI Auto-Layout feature, which aims to take care of basic board routing so you can iterate faster and get to market sooner.
Right now, Copilot is in a community beta. While it’s more capable than ever, it’s not perfect—and that’s where you come in. Your feedback will shape its evolution. Tell us what works, what doesn’t, and what actions you’d like Copilot to tackle next.
We’re rolling out new features in the coming weeks. If you don’t see them yet, keep an eye on Flux—or join our Slack and message Nico to get in early.
Ready to experience AI that truly takes action?
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