Navigating the Landscape of Free Sheet Metal Design and CNC Simulation Software

Executive Summary

The landscape of free software for sheet metal design and CNC fabrication presents a complex but navigable terrain for hobbyists, students, and emerging businesses. A successful choice hinges on understanding a fundamental trade-off between three core attributes: the software’s Capability (its feature set and power), its Accessibility (ease of use and hardware demands), and its Commercial Viability (the legal right to use it for profit and control over one’s data). No single free solution excels in all three areas; the optimal choice is therefore not a universal product but a strategic compromise tailored to the user’s specific needs and goals.

This report provides a comprehensive analysis of the available options, leading to three primary recommendations:

1. Autodesk Fusion 360 (Personal Use): The leading option for users who prioritize a polished, modern user interface and a seamlessly integrated CAD-to-CAM workflow for strictly non-commercial projects. Its power is undeniable, but it comes with significant functional limitations and data access constraints that must be carefully managed.
2. FreeCAD: The definitive choice for users requiring a powerful, unrestricted, and commercially viable open-source solution. It is the only platform that is truly free in every sense, offering complete freedom from licensing costs and usage restrictions. This freedom, however, comes at the cost of a steep learning curve and a less refined user experience that demands a significant investment of time and effort.
3. Hybrid Workflows: An advanced strategy for power users that leverages the strengths of multiple platforms. A typical hybrid workflow might involve using Onshape for its superior collaborative design interface and then transferring the model to FreeCAD for its unrestricted manufacturing file preparation, thereby bypassing the limitations of each individual platform.

It is crucial to clarify a common point of confusion at the outset. Within the context of free software, “CNC simulation” refers to either the geometric unfolding of a 3D model into a 2D flat pattern or the toolpath simulation for cutting operations (e.g., visualizing a laser or milling path). It does not encompass the sophisticated press brake process simulation—a kinematic visualization of the machine physically bending the part, complete with collision detection—which remains the exclusive domain of high-cost, professional offline programming (OLP) software.

Section I: The Ecosystem of Free Sheet Metal Fabrication Software

1.1 Deconstructing “Free”: A Taxonomy of No-Cost Software Models

The term “free” in the software world is not monolithic. It encompasses several distinct licensing and distribution models, each with profound implications for the user. Understanding these models is the first step in making an informed strategic decision.

1. Free and Open-Source Software (FOSS): This model is defined by granting users four essential freedoms: the freedom to use the software for any purpose, to study how it works, to modify it, and to distribute copies of the original or modified versions. FreeCAD and the 2D-centric
   LibreCAD  are the prime examples in this category. The paramount benefit is the complete absence of licensing fees, subscriptions, or restrictions on commercial use, making FOSS the only truly “free” option for businesses or individuals looking to profit from their designs.
2. Freemium / Personal Use Licenses: This is the dominant model for commercial-grade software offered at no initial cost. A powerful platform is provided for free to attract a large user base, but with a carefully crafted set of limitations designed to incentivize an upgrade to a paid subscription. Autodesk Fusion 360 and Onshape are the most prominent examples. The key restrictions almost invariably include a strict non-commercial use clause, the disabling of advanced features, and constraints on data access or privacy. Onshape’s model, for instance, makes all documents created on its free plan public by default, while Fusion 360 imposes a limit of 10 concurrently editable documents.
3. Trialware: This category consists of fully functional professional software made available for a limited evaluation period. BendSim, a professional press brake simulation suite, offers a 60-day trial, and Bend Wizard offers a similar trial for its graphical programming software. These are invaluable for short-term evaluation or for understanding the capabilities of high-end systems but do not represent a viable long-term free solution.

The choice of a software model is a strategic commitment. A FOSS platform like FreeCAD offers unparalleled freedom and long-term security from vendor-imposed changes, but at the cost of a steeper learning curve. Freemium platforms provide a more accessible entry point and a modern user interface but tether the user to a restrictive ecosystem they do not control. The history of Autodesk repeatedly altering the terms of the Fusion 360 personal license serves as a critical case study: users who invest significant time learning a freemium platform are building their skills and intellectual property on a foundation that can be changed or revoked at the vendor’s discretion. This stands in stark contrast to the FOSS model, where the user is part of a community-owned and directed ecosystem.

1.2 The Digital Workflow: From Concept to Bent Part

The journey from a digital idea to a physical, bent sheet metal part follows a distinct three-stage workflow. Understanding these stages is essential to grasp where different software tools fit into the process.

1. CAD (Computer-Aided Design): This is the creative stage where a 3D model of the part is conceived and constructed. The primary free tools for this task are FreeCAD, Autodesk Fusion 360, and Onshape. This phase is concerned with geometry, dimensions, and design intent.
2. CAM (Computer-Aided Manufacturing): This is the engineering stage where the 3D CAD model is translated into instructions that a CNC machine can understand. For sheet metal, this stage has two critical steps:
   • Unfolding: The 3D model is mathematically flattened into an accurate 2D pattern. This flat pattern is typically exported as a DXF or DWG file for use with laser cutters, plasma cutters, or waterjets.
   • Toolpath Generation: For cutting processes, the CAM software generates the specific path the cutting tool will follow, often output as G-code.
3. CNC Control Software: This is the operational stage. This software resides on the CNC machine’s controller and is responsible for interpreting the G-code or other instruction files from the CAM stage and commanding the physical movements of the machine’s motors and axes. LinuxCNC is a prominent open-source example of a CNC control system.

A common point of confusion is the distinction between CAM software and CNC control software. A program like LinuxCNC is not an alternative to FreeCAD or Fusion 360; it is the recipient of the files (e.g., G-code, DXF) that FreeCAD and Fusion 360 produce. The user’s query for “sheet metal bending software” and “CNC simulation” is primarily focused on the first two stages of this workflow: CAD and CAM.

1.3 Core Sheet Metal Principles in Software: The Physics of Bending

Accurate sheet metal fabrication relies on software that correctly models the physical principles of bending metal. The most critical of these principles are the K-factor, bend allowances, and bend reliefs.

1. The Foundation of Accuracy: K-Factor, Bend Allowance, and Bend Deduction: When a piece of sheet metal is bent, the material on the inside of the bend is compressed, while the material on the outside is stretched. Somewhere between these two surfaces lies a “neutral axis” that is neither compressed nor stretched and thus maintains its original length. This neutral axis does not remain at the center of the material’s thickness; it shifts toward the inside of the bend. The K-factor is a dimensionless ratio that represents the location of this neutral axis relative to the material thickness (K=Tt​, where t is the distance from the inside face to the neutral axis and T is the material thickness). This value is paramount for calculating the
   bend allowance (the length of the arc along the neutral axis) or the bend deduction (the amount the material appears to “grow” when flattened). These calculations are what allow the software to generate a flat pattern of the precise length required to achieve the final, correct dimensions after bending.
2. Software Implementation: Leading software packages provide robust tools for managing these parameters. Autodesk Fusion 360 and Onshape utilize comprehensive “Sheet Metal Rules” or tables that encapsulate material thickness, K-factor, bend radius, and corner relief information into a single, reusable profile. FreeCAD’s Sheet Metal Workbench also provides direct input fields for the K-factor and other critical parameters during the design process.
3. Preventing Failure: Bend Reliefs: Where two bends meet at a corner, immense stress is concentrated, which can lead to material tearing or unwanted deformation. To prevent this, software automatically or manually adds bend reliefs, which are small cuts (often round, square, or tear-shaped) at the end of a bend line.

While software provides sophisticated tools for these calculations, it is a recurring theme in user forums and professional advice that theoretical values are only a starting point. The most accurate parts are produced when using a K-factor derived from performing real-world test bends on the specific material, tooling, and press brake that will be used for production. The software’s default values, such as Fusion 360’s default K-factor of 0.44, should be treated as an educated guess, not an absolute truth. This grounds the theoretical power of the software in the practical realities of the workshop floor.

Section II: Analysis of Integrated CAD/CAM Platforms (Freemium Model)

The freemium model offers users access to powerful, commercially developed software at no cost, albeit with significant restrictions. Autodesk Fusion 360 and Onshape are the two dominant players in this space, each offering a distinct approach to sheet metal design.

2.1 Deep Dive: Autodesk Fusion 360 for Personal Use

1. Overview: Autodesk Fusion 360 is a powerful, cloud-enabled, and fully integrated platform that combines CAD, CAM, CAE (Computer-Aided Engineering), and PCB design into a single environment. It is widely recognized for its modern user interface, comprehensive feature set, and seamless workflow from design to manufacturing. It is frequently recommended as an excellent learning tool that serves as a stepping stone to professional-grade Autodesk products like Inventor.
2. Sheet Metal Design Environment: Fusion 360 features a dedicated “Sheet Metal” workspace. Design is governed by “Sheet Metal Rules,” which allow the user to pre-define material thickness, K-factor, and bend conditions. Its unified “Flange” tool intelligently combines the functionality of what were once separate tools for creating faces, edge flanges, and contour flanges, streamlining the modeling process. The software also includes distinct “Unfold” and “Create Flat Pattern” commands. The “Unfold” feature is a modeling tool used to temporarily flatten specific bends to perform operations (like cutting a hole across a bend line) before re-folding the part. In contrast, “Create Flat Pattern” generates the final, manufacturable flat view of the entire component.
3. CAM and Simulation Capabilities (in the Free Tier): The personal use license includes CAM capabilities for 2.5-axis and 3-axis milling, as well as turning. This functionality is used to generate G-code toolpaths for cutting the flat pattern on a CNC mill, router, or plasma table. The “Manufacture” workspace includes a toolpath simulation feature that animates the cutting process, allowing the user to visually inspect the tool’s path and check for collisions between the cutting tool and the workpiece. This should not be confused with press brake simulation.
4. Critical Limitations of the Personal Use License:
   • The 10 Active Document Limit: This is the most significant workflow constraint. A user can store an unlimited number of files in the cloud, but only 10 documents can be designated as “editable” at any given time. To edit an 11th document, another must be manually set to “read-only.” This requires constant project management and becomes particularly cumbersome when working with complex assemblies that reference many other parts.
   • Restricted File Exports: This is a major pain point for fabrication. While exporting 3D models in the universal STEP format is permitted, the crucial
     DXF export for 2D flat patterns is severely hampered. It cannot be done directly from the official “Flat Pattern” environment. The only workaround is to create a new sketch on the face of the flat pattern, project the geometry onto that sketch, and then right-click the sketch in the browser tree to “Save as DXF”. This process often results in the exported DXF including unwanted geometry like bend centerlines, which can confuse automated laser cutting software and may require manual cleanup in an external 2D program. Furthermore, exporting multi-sheet drawings as a PDF is disabled, with only single-sheet printing allowed.
   • Disabled Advanced CAM Features: The personal license lacks several key productivity features, including rapid moves and automatic tool changes. The lack of automatic tool changes means that any job requiring more than one tool must be posted as multiple, separate G-code files, a tedious process for the operator. All advanced multi-axis milling is also disabled.
   • Strictly Non-Commercial Use: The license explicitly forbids any commercial activity, including selling parts made with the software.
5. User Feedback and Reviews: Community feedback is generally positive regarding the software’s intuitive workflow and power, especially for those new to CAD/CAM. For sheet metal specifically, users report that it is a massive time-saver compared to trying to model bent parts using traditional solid modeling techniques. However, the license limitations are a frequent source of frustration and lengthy discussion threads in user forums.
6. System Requirements: Fusion 360 requires a modern 64-bit system. Minimum requirements are an x86-64 processor, 4 GB of RAM, and a DirectX11-capable graphics card. However, for a smooth and productive experience, a multi-core processor (e.g., Intel Core i7, AMD Ryzen 7), 16 GB of RAM or more, and a dedicated professional graphics card with at least 4 GB of VRAM are strongly recommended.

2.2 Deep Dive: Onshape Free Plan

1. Overview: Onshape represents a paradigm shift in CAD, operating as a fully cloud-native platform accessible through any modern web browser. Its foundational principles are radical real-time collaboration and zero IT overhead, as there are no installations, updates, or specific hardware requirements to manage.
2. Sheet Metal Design Environment: Onshape’s standout feature is its Simultaneous Sheet Metal This allows the user to view the 3D folded model, the 2D flat pattern, and the bend table all at the same time, in the same window. This provides instant, real-time feedback on how design modifications affect the final manufacturable pattern, eliminating the tedious “design, flatten, check, repeat” cycle that plagues many older CAD systems. The platform supports multiple modeling workflows, such as converting existing solids or building parts from scratch with flange tools. It also allows for the use of “Variable Studios” to define and control global parameters like material thickness and bend radii, which can be stored and reused across multiple projects, similar to gauge tables.
3. CAM and Simulation Capabilities: CAM and advanced simulation are not included in the core Onshape product or its Free Plan. These functions are provided through third-party applications available in the Onshape App Store or are bundled exclusively with the highest-tier Enterprise plans, designated as “EVP Only”.
4. Critical Limitations of the Free Plan:
   • Public-by-Default Documents: This is the most significant restriction and a deal-breaker for many. All design documents created under the Free Plan are publicly accessible and discoverable by other users on the internet. This makes the platform completely unsuitable for any proprietary, confidential, or private designs.
   • Strictly Non-Commercial Use: The Terms of Use explicitly state that the Free Plan is for non-commercial purposes only. Even selling a small number of 3D-printed parts designed on the platform is technically a violation of these terms.
5. File Interoperability: This is a major strength of Onshape. The Free Plan allows for exporting to a wide array of industry-standard formats, including STEP, IGES, Parasolid, and, crucially for manufacturing, clean DXF and DWG files generated directly from the flat pattern view. This export functionality does not suffer from the same issues of extraneous geometry seen in Fusion 360’s free tier.
6. User Feedback: Users transitioning from traditional file-based CAD systems consistently praise Onshape’s modern, collaborative workflow and are particularly enthusiastic about the productivity gains from the simultaneous flat pattern view. The initial lack of sheet metal tools was once a major barrier to adoption, but this has since been robustly addressed and is now considered a core strength. The primary struggles new users face often relate to understanding the unique Onshape-specific workflow, such as learning to use the dedicated sheet metal tools correctly rather than trying to apply traditional solid modeling techniques.
7. System Requirements: Onshape has the most lenient system requirements of any major CAD platform. As a browser-based application, the only essential requirements are a stable internet connection and a computer (including low-power devices like Chromebooks) or a supported mobile device running a modern web browser with WebGL enabled.

Section III: The Open-Source Champion: A Comprehensive Analysis of FreeCAD

3.1 Core Architecture and Philosophy

FreeCAD stands apart as a powerful, general-purpose 3D modeling application built on a foundation of free and open-source principles.

1. A True Parametric Modeler: At its core, FreeCAD is a feature-based parametric modeler. Every object in a design is defined by a history of operations (e.g., sketch, pad, pocket, fillet) and their associated parameters (e.g., length, angle, radius). Modifying any parameter or feature early in the history tree will propagate the change through the entire model, allowing for complex, editable designs.
2. The Workbench Concept: The software’s immense power and notable complexity stem from its modular architecture. All functionality is organized into distinct “Workbenches,” which are specialized toolsets for specific tasks. A user might start in the “Sketcher” workbench to create a 2D profile, move to the “Part Design” workbench to extrude it into a 3D solid, switch to the “Sheet Metal” workbench to add bends and flanges, and finally use the “Path” workbench for CAM operations.
3. Uncompromising Freedom: As a FOSS project licensed under the LGPL, FreeCAD is completely free for everyone to download, use, modify, and distribute for any purpose, forever. There are no license fees, no subscriptions, and absolutely no restrictions on commercial use, making it a uniquely powerful tool for startups and small businesses.

3.2 The Sheet Metal Workbench: The Heart of Fabrication

The ability to design for sheet metal fabrication in FreeCAD is enabled by a dedicated, community-developed addon workbench.

1. Installation and Nature: The Sheet Metal workbench is not part of the default FreeCAD installation but can be easily added through the built-in “Addon Manager”. Its origin as a community project means its development is ongoing, with efforts to integrate its functionality more deeply into the FreeCAD core.
2. Core Tools and Workflow: The typical workflow begins by creating a base feature, either from a 2D sketch or by converting an existing solid part using the Make Base Wall tool. Flanges are then added to edges using the Make Wall tool, with their properties (length, angle, relief type) being parametrically controlled in the “Data” pane of the Combo View. To create the final manufacturable pattern, the user selects a stationary face on the model and uses the Unfold tool. This generates a new, separate object in the model tree representing the flattened part, which importantly contains a linked 2D sketch that can be directly exported for manufacturing. The workbench provides full parametric control over essential variables like material thickness, bend radius, and K-factor.
3. Versatility: The underlying principles of unfolding are not exclusive to metal. The Sheet Metal workbench is frequently used by makers and designers for projects involving other foldable sheet materials, such as creating packaging from cardstock or enclosures from acrylic that will be bent with heat.

3.3 The Path Workbench: Integrated Open-Source CAM

FreeCAD includes its own integrated CAM module, the “Path” workbench, which allows users to generate machine instructions without leaving the application. It is capable of creating G-code for a variety of 2.5D operations, including profiling, pocketing, drilling, and v-carving. This makes it perfectly suited for programming the CNC routers, mills, laser cutters, or plasma cutters that would be used to cut the 2D flat pattern generated by the Sheet Metal workbench. The Path workbench also includes a basic toolpath simulator to visualize the cutting process.

3.4 Unrestricted Interoperability: The “Swiss Army Knife” of File Formats

A key strategic advantage of FreeCAD is its extensive support for a vast range of open and proprietary file formats. It can natively import and export STEP, IGES, OBJ, STL, SVG, and DXF files. It can also handle the proprietary DWG format with the help of an external file converter utility, which the software guides the user to install.³ This robust file support, combined with its lack of licensing restrictions, positions FreeCAD as an ideal central hub in a hybrid workflow. It can be used to import a file from a more restrictive program (like a model from Onshape’s free plan), process it, and then export it in a clean, open format for manufacturing, effectively acting as a free “Rosetta Stone” for CAD data.

3.5 Challenges and User Experience: The “Cost” of Freedom

FreeCAD’s unparalleled freedom is not without its costs, which are paid primarily in the user’s time, effort, and patience.

1. The Learning Curve and UI/UX: This is FreeCAD’s most frequently cited weakness. The user interface is widely considered to be less intuitive, “clunky,” and inconsistent when compared to the polished experience of commercial software. This presents a significant learning barrier for new users and can slow down workflows even for experienced practitioners.
2. The Topological Naming Problem: A long-standing and well-documented core issue in FreeCAD relates to how it internally names and references geometric features like faces and edges. Making changes to features early in the model’s history tree can cause the names of subsequent features to change, breaking the model and causing errors that are difficult to resolve. This makes the iterative design process more fragile than in commercial modelers and is a major source of frustration.
3. Performance and Stability: While capable of handling very complex designs, the software can become slow, unresponsive, and occasionally unstable when working with models that have very long and intricate feature histories.
4. Development State and Community: The Sheet Metal workbench itself has known areas targeted for improvement. For example, the “Unfold” object is not yet fully parametric; if the original 3D model is changed, the unfolded version must be manually deleted and recreated. There is a strong community desire to rewrite some core logic from Python to C++ for substantial performance gains.

Despite these challenges, the “cost” of using FreeCAD is heavily mitigated by a large, active, and helpful global community. This community produces a wealth of tutorials, videos, and documentation and provides invaluable support in forums. Furthermore, the project is under active development, with strategic efforts by groups like Ondsel focused on improving core issues, including a major refactoring of the Sheet Metal workbench. Choosing FreeCAD is an investment in a community-owned project that is on a positive and steady trajectory of improvement.

3.6 System Requirements

FreeCAD is extremely flexible in its hardware requirements. It is fully cross-platform, running natively on Windows, macOS, and various Linux distributions. It can be run on a wide range of hardware, including older and less powerful machines that would struggle with commercial CAD packages. However, as with any CAD software, working on large and complex models will benefit significantly from a powerful multi-core CPU and ample RAM.

Section IV: Professional Bending Simulation (Trialware Insights)

4.1 Defining Offline Programming (OLP) and True Bending Simulation

A significant expectation gap exists between the “simulation” offered by free tools and the capabilities of professional software for press brakes. This section aims to manage that expectation by defining what true bending simulation entails. Professional software in this domain is referred to as Offline Programming (OLP) software. Its primary purpose is to fully program the press brake on a separate computer while the machine remains in production, thereby maximizing uptime and ensuring a correct part on the first attempt.

The core features of professional OLP software, which are absent in all free tools, include:

1. Automatic Bend Sequencing: The software analyzes the 3D part geometry and automatically calculates the most efficient and physically possible order of bends to create the final part.
2. Automatic Tool Selection and Setup: It intelligently selects the appropriate punches and dies from a digital library of the workshop’s actual tooling inventory and calculates the optimal placement of these tools along the press brake bed.
3. Full 3D Kinematic Simulation: This is the “true” bending simulation. It provides a full 3D animation of the entire bending process, showing the machine’s ram, backgauge, and tooling in motion. Crucially, it performs a comprehensive collision check, detecting any potential impacts between the workpiece and the machine frame, ram, tools, or backgauge fingers.
4. Machine-Specific Post-Processing: After a valid, collision-free sequence is confirmed, the OLP software generates the precise NC program (G-code or proprietary format) tailored to the specific make and model of the press brake’s controller.

4.2 A Glimpse into the Professional World: Analysis of Commercial Systems

By examining commercial systems available as limited-time trials, one can appreciate the complexity and power of professional-grade tools.

1. BendSim (from Cincinnati): The availability of a 60-day full-function trial and an exceptionally detailed user manual makes this an excellent case study. The manual reveals the immense complexity involved in configuring a virtual machine twin, with dozens of tabs and hundreds of parameters for defining machine dimensions, tonnage, speeds, backgauge types, axis travel limits, tool holder styles, and user preferences. This demonstrates the depth of simulation required for professional accuracy.
2. Radbend (from Hexagon): Noted as a market-leading solution, Radbend’s key value proposition is being machine-independent. A single license can be configured to program an entire workshop’s fleet of different press brake brands (e.g., Amada, Bystronic, Trumpf, LVD), offering tremendous production flexibility.
3. MBend (from Metalix): This software is highlighted for its highly realistic visualization, which includes simulating material properties like overbend and springback, and its ability to program complex multi-finger backgauge movements for precise part positioning.

4.3 Key Takeaways: The Functional Gap Between Free and Professional

The fundamental missing link in all free software is the machine and tooling context. FreeCAD and Fusion 360 operate in a purely geometric space; they calculate a flat pattern based on an idealized K-factor and material thickness. Professional OLP software operates within the defined physical constraints of a specific, real-world machine and its inventory of available tools. The value of OLP lies in preventing costly setup errors, material waste, and machine downtime by proving out the entire process virtually, embodying the “first time right” manufacturing principle. This clear return on investment is what justifies the high cost of such systems.

For the user of free software, this means that for any part with more than a few simple bends, the software will provide the essential flat pattern, but the user is still responsible for manually planning the bend sequence, checking for potential collisions (either mentally or with a physical prototype), and manually programming the sequence into the press brake controller.

Section V: The Complete Workflow in Practice: Step-by-Step Guides

This section translates the preceding analysis into practical, step-by-step guides for creating a simple sheet metal part using the three primary free workflows.

5.1 The Integrated Path: A Simple Bracket in Fusion 360

1. Initiate a new design and switch to the Sheet Metal
2. From the Modify menu, select Sheet Metal Rules. Create or select a rule that defines your material, such as “Aluminum (in)” with a 1.2 mm thickness and a 0.44 K-factor.
3. Create a 2D sketch of the bracket’s base profile and use the Flange tool to create the initial base feature.
4. Select an edge of the base feature and use the Flange tool again to add a 90-degree bend.
5. To add a feature across a bend, select the Unfold tool from the Modify Select a stationary face and the bend you wish to flatten. Create a sketch on the unfolded surface (e.g., for a hole) and use the Extrude tool to cut through the part. Finally, click Refold Faces in the toolbar to restore the bend.
6. From the Create menu, select Create Flat Pattern. Select a stationary face to generate the flat pattern view in a separate environment.
7. Navigating the Export Limitation: To export for manufacturing, Finish Flat Pattern. Create a new sketch on the flat face of your model. Project the geometry of the flat pattern onto this new sketch. In the browser tree on the left, find this new sketch, right-click on it, and select Save as DXF. Be aware that this DXF may contain extra lines (like bend centerlines) that need to be removed in a 2D editor before sending to a laser cutter.

5.2 The Open-Source Path: A Simple Enclosure in FreeCAD

1. If not already present, install the Sheet Metal workbench using the Tools > Addon Manager.
2. In the Part Design workbench, create a base solid, such as a rectangle extruded with the Pad
3. Switch to the Sheet Metal Select the padded solid and use the Make Base Wall tool to convert it into a sheet metal object, defining its thickness.
4. Select the edges where you want to add walls and use the Make Wall The properties of the new flanges, such as length and angle, can be adjusted parametrically in the Data tab of the Combo View panel.
5. To add features like holes, switch back to the Part Design Create a new sketch on a face, draw the hole profile, and use the Pocket tool to perform a boolean cut.
6. To flatten the part, switch back to the Sheet Metal Select a face that will remain stationary and click the Unfold tool. This will create a new “Unfold” object in the model tree.
7. Unrestricted Export: Expand the “Unfold” object in the tree. You will see a sketch object (e.g., “SketchUnfold”). Select this sketch and go to File > Export. Choose the DXF or SVG format to save a clean, manufacturing-ready 2D file.

5.3 The Hybrid Power-User Path: The Best of All Worlds

This advanced workflow combines the strengths of multiple platforms to achieve a professional result for non-commercial projects, free of charge.

1. Design Phase (Onshape): Use Onshape’s Free Plan to design the part. Take full advantage of the simultaneous flat pattern view for rapid, error-free iteration and complex geometry creation.
2. Export Phase (Onshape): Once the design is finalized, export the 3D model as a universal STEP file. This is an unrestricted and robust export option in Onshape’s free tier.
3. Manufacturing Prep Phase (FreeCAD): Launch FreeCAD and import the STEP file you just created. FreeCAD’s excellent support for standard formats will ensure the geometry is imported faithfully.
4. Final Output (FreeCAD): Use FreeCAD’s Sheet Metal workbench to unfold the imported model and export a clean DXF for laser/plasma cutting. Alternatively, use the Path workbench to generate G-code directly for a CNC router or mill. This workflow combines the superior design UI of Onshape with the unrestricted manufacturing output of FreeCAD, effectively bypassing the primary limitations of both platforms (Onshape’s public data and Fusion’s crippled exports).

Section VI: Comparative Analysis and Strategic Recommendations

The choice of software is a strategic decision that depends heavily on the user’s context, priorities, and technical comfort level. The following table and recommendations aim to distill the preceding analysis into a clear decision-making framework.

Table 6.1: Feature Comparison Matrix of Leading Free Sheet Metal Software

6.1 Final Recommendations for Specific User Personas

• For the Hobbyist/Maker:
  • Primary Recommendation: Fusion 360. For one-off projects, the polished interface and integrated CAM provide the fastest and most intuitive path from an idea to a cut part. The 10-document limit and DXF export workarounds are manageable annoyances for non-commercial, intermittent use.
  • Alternative: FreeCAD. If the user is passionate about open-source principles, anticipates creating a large library of designs over time, or finds the Fusion 360 limitations to be a significant barrier, investing the time to learn FreeCAD is a superior long-term strategy.
• For the Student:
  • Primary Recommendation: Fusion 360 or Onshape (with Education License). Students should apply for the full educational licenses offered by Autodesk and Onshape. These licenses remove the restrictions of the personal/free plans and provide invaluable experience with the same professional tools used widely in industry.
  • Secondary Recommendation: FreeCAD. FreeCAD remains an essential tool for any engineering student who wishes to understand the fundamental principles of parametric modeling, CAM, and open-source software development, rather than simply learning to operate a specific commercial product.
• For the Bootstrapped Startup / Small Business:
  • Primary Recommendation: FreeCAD. It is the only viable option that is truly free and legal for commercial use. The challenges of its user interface represent a real business cost in terms of training time and potential workflow inefficiencies. However, this is often a more acceptable cost than the legal risks or high subscription fees of commercial software. The optimal strategy is often to have a dedicated team member become the in-house FreeCAD expert.
  • Strategic Growth Path: A new business can start with FreeCAD for all proprietary commercial work. As revenue grows, the first investment in paid software can be made. This could be a full Fusion 360 subscription, Onshape Standard, or a professional 2D tool like DraftSight or SolidWorks, depending on which part of the workflow presents the biggest bottleneck.

6.2 The Future of Free Sheet Metal Software: A Concluding Outlook

The landscape of free fabrication software is dynamic and constantly evolving. The steady, community-driven improvement of FreeCAD, exemplified by strategic projects to enhance core components like the Sheet Metal workbench, runs parallel to the calculated use of freemium models by industry giants like Autodesk and PTC/Onshape. This competitive tension ultimately benefits the end-user by providing a range of powerful options at little to no monetary cost. While the functional gap between free and professional tools may narrow over time, the fundamental philosophical difference — community-driven freedom versus commercially-controlled access —will likely remain the central axis around which a user’s choice revolves.