Top 9 Open Source CAD Software for 2D and 3D Design

Open source CAD software is primarily defined by its publicly accessible source code. This key characteristic means users can freely view, modify, and distribute the software.

The core principles are transparency in development and strong community collaboration. For AEC professionals, this means greater control over workflows, deeper flexibility in deployment, and lower upfront costs.

An open source CAD program democratises access to powerful design tools. Smaller practices and independent designers can access capable CAD tools without steep software investment. Custom integrations are also easier to build.

For example, a Melbourne-based engineering startup recently used FreeCAD to prototype modular housing designs, which slashed software costs by 60%. For reference, kindly check the details of AutoCAD license pricing in Australia here.

Top Open Source CAD Software

The world of open source CAD software is surprisingly diverse. Some tools specialise in traditional 2D drafting, while others tackle complex 3D parametric modeling. Others still serve niche needs like programmatic design or architectural visualisation.

Below, we’ve curated the most relevant platforms for AEC use. Each tool brings its own advantages. The key is to match software capability with your project needs and goals.

1. LibreCAD

LibreCAD stands out as a free open source 2D CAD application. For us, LibreCAD is one of the best CAD for beginners.  It supports DXF and DWG file formats, making it compatible with many existing AEC workflows. The interface is clean and intuitive, especially for those familiar with traditional CAD systems.

• Pros: free, easy to use, cross-platform
• Cons: no 3D modeling features
• Best for: small firms, students, and drafters needing a straightforward 2D CAD solution.

2. FreeCAD

FreeCAD is an open source parametric 3D CAD modeler with strong BIM capabilities. Being free, designs can be modified by changing parameters. It includes an ‘Arch’ workbench for BIM-like tools and supports the IFC format. FreeCAD is ideal for technical drawings, schematics, and simple plans.

• Pros: Parametric modeling, growing BIM support, cross-platform compatibility
• Cons: Steeper learning curve, less polished UI
• Best For: User who explores 3D modeling and open BIM in an AutoCAD alternative.

3. QCAD

QCAD is another 2D-focused open source CAD software with an interface reminiscent of AutoCAD. It’s known for its precision and ease of use. QCAD is lightweight and great for technical drawings and plans. The community edition is free, while the QCAD Pro version unlocks more features.

• Pros: User-friendly, good for technical drawings, affordable upgrade path
• Cons: Lacks 3D modeling, limited advanced features in the free version
• Best For: Drafters, architects, and students wanting a structured 2D environment.

4. OpenSCAD

OpenSCAD is a unique and script-only open source CAD software. Yup, think CAD meets scripting. It’s highly precise and ideal for repeatable parts and configurations.

• Pros: Programmatic design, version control-friendly, excellent for mechanical parts
• Cons: Not ideal for organic shapes, requires coding knowledge
• Best For: Engineers and coders working on parameter-driven components.

5. BRL-CAD

BRL-CAD is open source solid modeling. The software uses constructive solid geometry for robust 3D modeling. It’s free, with powerful analysis and ray-tracing tools. Please note, the complex interface and CSG approach aren’t beginner-friendly.

• Pros: High accuracy, robust geometric analysis, ray-tracing capabilities
• Cons: Complex interface, steep learning curve
• Best For: Engineers working on high-precision or defence-grade models, not architectural layouts.

6. SolveSpace

SolveSpace is an open source parametric 2D and 3D CAD tool. It supports various file formats, including DXF, STL, and STEP. Also, SolveSpace supports NURBS surfaces. Yup, it’s small in size but surprisingly capable.

• Pros: Lightweight, constraint solver, accurate geometry
• Cons: Unconventional UI, limited 3D feature set
• Best For: mechanical part design, small assemblies, 3D printed parts, and users preferring logic-based modelling.

7. Blender

While not primarily CAD, Blender is an open source 3D creation suite. Its 3D modelling, rendering, and animation capabilities make it a favourite for visualisation. The steep learning curve and lack of CAD precision are drawbacks. An AutoCAD vs SketchUp comparison for visualisation capabilities might highlight Blender’s strengths in rendering.

• Pros: Powerful visual tools, active community, great for presentations
• Cons: Not a precision CAD tool, lacks engineering features
• Best For: Architectural visualisation, animations, and conceptual renders needing high-end renderings or walkthroughs.

8. nanoCAD

nanoCAD offers a free CAD software basic version, with paid modules for extended capabilities. The free version is strong for 2D work, while paid modules unlock 3D. A key advantage is its cost-effective CAD and full native DWG support.

• Pros: Full DWG compatibility, affordable, familiar interface
• Cons: Limited 3D features without add-ons
• Best For: Budget-conscious SMEs needing DWG support.

9. Sweet Home 3D

Sweet Home 3D is a free interior design and space planning tool for floor plans, room layouts, furniture placement, and simple interior visualisation. It is more relevant to AEC-adjacent work than LeoCAD, which is mainly built around virtual LEGO models.

• Pros: Free, simple layout workflow, useful for room planning
• Cons: Limited CAD control, limited BIM control, not suited to formal documentation
• Best For: Interior layout studies, early spatial planning, and simple stakeholder conversations before formal CAD documentation begins.

Sweet Home 3D fits the stage where your team needs to discuss space before it needs to issue controlled drawings. Its feature set covers walls, floor plans, doors, windows, furniture, dimensions, and room areas.

A fitout team might use Sweet Home 3D to test a basic room arrangement before a designer turns that thinking into proper CAD documentation. That keeps the tool in the right place: useful for early layout thinking, not responsible for project records.

With the CAD tools options above, and your team still needing controlled DWG workflows, maybe you really need Interscale’s Autodesk AutoCAD software licensing support before treating open-source CAD as the whole answer.

Open Source CAD vs Paid CAD

Open source CAD is usually better for cost control, testing, training, and lighter workflows, while paid CAD is usually stronger for governed documentation, DWG continuity, support, and production accountability.

For Australian SMEs, the decision between open-source CAD and a paid tool could come down to drafting control, file exchange, support, and how much cleanup the team can tolerate as drawings move between consultants, contractors, and internal reviewers.

The table below helps you visualise the decision factors between open-source CAD and a paid tool.

Decision area	Open source CAD	Paid CAD
Upfront cost	Often free, which can help with testing, training, and non-critical drafting. The real cost sits in setup time, file testing, user training, and internal support.	Usually subscription-based or licence-based. Costs are higher, but easier to plan when the tool is part of a production workflow.
2D drafting	LibreCAD and QCAD can suit simple plans, details, layouts, and DXF-based drafting. Test layers, lineweights, dimensions, blocks, title blocks, and PDF plotting before rollout.	Tools like AutoCAD are usually stronger where DWG continuity, drawing standards, sheet setup, xrefs, and documentation control matter.
3D modelling	FreeCAD can support parametric modelling and open BIM exploration, especially after FreeCAD 1.0. Test constraints, assemblies, repeated edits, IFC export, and drawing output before using it on live work.	Paid CAD and BIM tools usually offer more mature workflows for complex models, documentation sets, multi-user coordination, and revision-heavy projects.
Visualisation	Blender is strong for renders, walkthroughs, concept imagery, and presentation material. It should not become the controlled model or drawing source.	Paid design suites may connect visualisation more directly with the production model, materials, views, documentation sets, and revision updates.
File compatibility	Support varies by tool. QCAD Professional lists DWG and DXF read-write support across many AutoCAD format versions, but teams should still test real consultant files.	Usually stronger when teams need cleaner DWG exchange, vendor-backed compatibility, xref handling, plotting consistency, and fewer handover surprises.
Support model	Usually relies on community forums, documentation, and internal technical confidence. Someone in the team needs to own setup, testing, templates, and troubleshooting.	Usually includes clearer vendor support, scheduled updates, commercial documentation, training pathways, and account management.
Workflow risk	Works best when the team can test real files before adoption and keep open source tools in the right role.	Often safer when drawings carry approval pressure, consultant dependencies, contractual records, or delivery deadlines.

From the table above, you can see how file compatibility is the row that usually turns the comparison into a workflow decision. A 40-person consultancy in Perth might receive DWG files from an architect, export DXF for a subcontractor, and issue PDFs for project records.

If layers, title blocks, dimensions, xrefs, or lineweights shift during exchange, the team loses time in checking and cleanup. That kind of friction can quietly outweigh the savings from using a free tool.

But please remember that does not mean open source CAD is the wrong choice. It means the role of each tool should be clear. FreeCAD may suit parametric testing. QCAD may suit 2D drafting. Blender may suit visualisation. Paid CAD may still remain the safer production backbone.

That’s why, at Interscale’s software licensing service, we do not treat open-source and paid CAD as opposing choices.

We help your teams identify the right software mix based on drafting needs, file exchange risks, team capacity, and growth plans.

Or, if you’re still weighing open-source CAD against paid tools on your own, our guide on how to choose CAD software offers a broader way to think about workflow fit.

Your Next Step

Choosing the right CAD tools is about aligning design technology with your business goals. That’s why open source CAD software can be a smart move. But it can be risky when you jump in without a clear understanding of its limitations, licensing nuances, or integration requirements. That’s why we focus on building tailored software strategies.

Our team is here to help you assess, manage, and optimise your entire design technology stack. And if you need this kind of support system, let’s talk. We invite you to book a free discovery session with our team. In that meeting, we can discuss how to align your tools with your goals. Book a free consultation today.