Expert Verified — Written by Keyur Rakholiya, SurgePV Editorial. 10 tools compared for solar structural design. Pricing verified July 2026. Based on 1+ GW of delivered projects across 50+ countries, including hundreds of structural reviews for permit approval.
Every solar array is a structural problem before it is an electrical one. Panels, rails, and ballast add dead load. Wind adds uplift. Snow adds point loads the roof designer never planned for. Get the structure wrong and the best yield simulation in the world means nothing.
We compared 10 tools that handle the structural side of solar design in 2026. Some model ground-mount civil works. Some turn drone flights into inch-accurate roof models. Some are free racking configurators that output wind and snow load calculations. Each earns its place for a different job.
One honesty note up front. No software on this list replaces a licensed structural engineer. Most building departments require a stamped review. These tools make that review faster, cheaper, and less error-prone. For a deeper look at the assessment workflow itself, read our guide to rooftop solar structural assessment.
Quick Picks
| Pick | Tool | Why |
|---|---|---|
| Best for utility-scale ground mounts | PVCase | Terrain-following layouts, grading analysis, 4 TW designed annually |
| Best for cloud-based civil engineering | RatedPower | Earthworks, layouts in under 60 seconds, unlimited users |
| Best for drone-accurate roof surveys | Scanifly | 1 to 3 inch measurement accuracy from photogrammetry |
| Best for permit-ready plan sets | PVComplete | PE stamps and plan sets for all 50 US states |
| Best free racking design | IronRidge Design Assistant | Certification letters with wind and snow loads at $0 |
| Best for 3D layout feeding structural review | SurgePV | Fast 3D rooftop design with accurate array geometry and BOM |
How We Evaluated
We scored each tool on 5 criteria. Weighting reflects what actually gets projects permitted and built.
| Criterion | Weight | What We Measured |
|---|---|---|
| Structural depth | 30% | Load calculations, racking logic, grading, foundation support |
| Accuracy of inputs | 25% | Roof measurement precision, terrain data, wind and snow maps |
| Permit readiness | 20% | Stamped letters, plan sets, code references (ASCE 7, Eurocode) |
| Workflow fit | 15% | How well it connects to layout, electrical, and yield tools |
| Cost | 10% | License price versus project volume and hardware lock-in |
At-a-Glance Comparison
| Tool | Best For | Starting Price | Free Tier | Cloud | Standout |
|---|---|---|---|---|---|
| PVCase | Utility-scale ground mounts | Custom | 14-day trial | Limited (AutoCAD plugin) | 80–90% design time savings |
| RatedPower | Cloud civil engineering | Custom | Demo only | Yes | Layouts in under 60 seconds |
| Scanifly | Drone roof surveys | Custom (credit-based) | No | Yes | 1 to 3 inch accuracy |
| PVComplete | Permit-ready plan sets | $180/mo | 7-day trial | No (AutoCAD plugin) | PE stamps for 50 states |
| Virto Solar | CAD-native C&I engineering | €2,980/yr | No | No (CAD plugin) | Mounting manufacturer APIs |
| SurgePV | 3D layout for structural review | $1,899/yr (3 users) | Free trial | Yes | Design-to-proposal in 1 platform |
| PV*SOL Premium | Mounting-integrated rooftop design | €845/yr | 30-day trial | No (Windows) | K2 Base and Renusol integration |
| IronRidge Design Assistant | Free residential racking design | $0 | Free forever | Yes | Stamped certification letters |
| Unirac U-Builder | Free commercial racking design | $0 | Free forever | Yes | Wind and snow load reports |
| K2 Base | Free European mounting planning | $0 | Free forever | Yes | Eurocode static verification |
1. PVCase — Best Structural Design Software for Utility-Scale Ground Mounts
PVCase is the AutoCAD-based platform behind a large share of utility-scale engineering work. Customers design 4 TW of projects annually on it (PVCase, 2026), and structural layout is where it earns its keep.
What It Does Well
Ground Mount handles the parts of structural design that utility projects actually fight over. Terrain-following tracker placement adapts rows to real topography. The civil analysis runs cut-and-fill grading estimates early, so earthwork risk shows up before the bid, not after.
Roof Mount covers the C&I rooftop side with direct drone data integration from Airteam and mounting integrations including PanelClaw, with K2 Systems upcoming. Users report 80–90% design time savings on ground-mount work and 60–70% on rooftops (G2, 397 reviews, 4.7 out of 5).
Our Take: If your structural problems live on 20 MW of rolling terrain, PVCase is the strongest option we tested. It assumes you already live in AutoCAD and can pay enterprise prices.
Where It Falls Short
Ground Mount and Roof Mount are Windows-only AutoCAD plugins, not cloud products. There is no virtual machine support and no built-in component database, so structural hardware specs go in manually. Pricing is custom and users cite cost as a barrier for small businesses. It also does not produce stamped structural calculations; a structural engineer still signs.
Key Features
- Terrain-following tracker and fixed-tilt layout
- Cut-and-fill grading and civil analysis
- Drone-derived 3D building models on Roof Mount
- Mounting system integrations (PanelClaw, K2 Systems upcoming)
Pricing
- Ground Mount / Roof Mount / Yield: Custom pricing, contact sales
- Free trial: 14 days; free licenses for students and educators
Who Should Use PVCase
Strong fit: Utility-scale developers and EPCs with AutoCAD-literate engineering teams. Probably not right for: Residential installers, Mac shops, and teams without CAD experience.
2. RatedPower — Best for Cloud-Based Civil and Structural Layout
RatedPower automates utility-scale plant engineering in the browser. Over 4,300 solar professionals across 130+ countries use it, with 43+ GW of developed projects on the platform (RatedPower, 2026).
What It Does Well
Speed is the story. Automatic layout generation finishes in under 60 seconds, and users report roughly 75% design time reduction versus AutoCAD workflows. The earthworks tool and 3D layout model calculate grading volumes directly, which is the structural number that moves utility-scale budgets most.
Every plan includes unlimited users, projects, and designs. For an engineering team where 5 people touch the same plant, that pricing model beats per-seat CAD licenses. G2 reviewers rate RatedPower 4.5 out of 5 across 252 reviews.
Our Take: RatedPower is the fastest way to get a structurally plausible utility-scale layout with earthworks numbers attached. Treat its output as pre-engineering; detailed structural design still happens downstream.
Where It Falls Short
There is no free plan and no public pricing, and users call it expensive. It does not serve rooftop, residential, or small C&I at all. Post and foundation engineering is indicative, not stamped, so you still need a geotechnical and structural engineer for construction documents.
Key Features
- Automated layout with earthworks and 3D terrain modeling
- P75/P90/P95/P99 bankable yield estimates
- DWG, KML, and PVsyst scene export
- Bill of quantities and cable and post listings in Excel
Pricing
- Basic, Advanced, Enterprise tiers: Custom quotes, unlimited users on all tiers
- Free trial: None; free product tour and live demo available
Who Should Use RatedPower
Strong fit: Utility-scale developers and EPCs who need fast, bankable pre-engineering with civil quantities. Probably not right for: Rooftop installers and anyone needing stamped structural calculations.
3. Scanifly — Best for Drone-Accurate Rooftop Structural Surveys
Scanifly is the drone-first platform for turning a roof into a measured 3D model. Structural design is only as good as the roof geometry underneath it, and that is exactly what Scanifly fixes.
What It Does Well
DroneDesign builds photogrammetry models with 1 to 3 inch measurement accuracy across all axes. Rafter spacing, parapet heights, obstruction offsets: the numbers a structural engineer asks for on day 1 arrive before the truck rolls. Namaste Solar cut its design revision rate from 25% to under 1% after switching (Scanifly, 2026).
The January 2026 IronRidge integration pushes measured array geometry straight into racking design, saving a reported 1 to 3 hours per project. Scanifly’s shading tool is also the only drone-based option approved by programs including NYSERDA, MassCEC, and the California Energy Commission (Scanifly, 2026).
Our Take: Bad roof measurements kill more structural designs than bad math. Scanifly eliminates the measurement problem. You still need separate tools for load calculations and stamps.
Where It Falls Short
Subscription pricing is not public, and design services run on a credit system that takes learning. Processing needs a desktop workstation, not a laptop in the field. Image quality issues like glare and cloud cover can force re-flights, and large utility-scale work is out of scope.
Key Features
- Photogrammetry 3D models accurate to 1 to 3 inches
- PrelimDesign remote designs plus DroneDesign onsite verification
- IronRidge, K2 Systems, SnapNrack, and Unirac racking integrations
- CAD export, BOM generation, and engineering plan sets
Pricing
- Subscription: Custom; contact Scanifly for quotes
- Design services: Credit-based (residential site model from 15 credits)
Who Should Use Scanifly
Strong fit: Residential and C&I installers who want survey-grade roof data before structural design. Probably not right for: Teams wanting published pricing or utility-scale workflows.
4. PVComplete — Best for Permit-Ready Structural Plan Sets
PVComplete, acquired by Enact Solar in January 2026, builds AutoCAD-native solar engineering tools. Over 500,000 projects have been designed with it since 2015 (PVComplete, 2026).
What It Does Well
PVCAD generates permit-ready plan sets, and that is where structural documentation lives. Automated layout, single-line diagrams, and plan set generation claim a 50% design time reduction. The differentiator is the engineering services layer: PE stamps and compiled plan sets for all 50 US states.
For installers without an in-house engineer, that service closes the structural gap. You design in PVCAD, and licensed engineers stamp what your Authority Having Jurisdiction (AHJ) needs. PVSketch covers quick feasibility work in the browser before CAD work starts.
Our Take: PVComplete is the practical route to stamped structural documents without hiring a PE. The software itself is unremarkable next to PVCase; the stamp pipeline is the product.
Where It Falls Short
There are no reviews on G2, Capterra, or TrustRadius, so independent validation is thin. PVCAD requires AutoCAD skills and carries a steep learning curve. PVSketch’s equipment database is outdated, and the post-acquisition roadmap is still settling.
Key Features
- AutoCAD-native PVCAD with permit-ready plan sets
- PE stamps and engineering services for all 50 US states
- PVSketch web tool for early feasibility
- PVsyst 3D scene export for yield modeling
Pricing
- PVCAD plug-in: $180/month (bring your own AutoCAD)
- PVCAD Bundle: $245/month with AutoCAD OEM license
- PVCAD Mega: From $295/month for utility-scale
- Free trial: 7 days on PVCAD products
Who Should Use PVComplete
Strong fit: US installers who need stamped plan sets and lack in-house engineering. Probably not right for: Teams wanting validated user reviews or non-AutoCAD workflows.
5. Virto Solar — Best for CAD-Native C&I Engineering with Mounting Integrations
Virto Solar is a Belgian engineering software company focused on C&I and utility-scale design. Its Virto.CAD plugin for AutoCAD and BricsCAD targets construction-ready engineering.
What It Does Well
The mounting manufacturer integrations are the structural story. Virto connects via API to racking makers including PanelClaw, Aerocompact, Avasco Solar, and Van der Valk. Layouts carry real racking data instead of generic blocks, and the BOM generation earns direct praise in G2 reviews (4.6 out of 5, 21 reviews).
Virto claims an 80% design time reduction through automated layouts and string plans. Virto.MAX, the browser tool, handles rapid conceptual design up to and beyond 1 MW, then hands off to Virto.CAD for detailed engineering. Direct PVsyst export keeps the yield workflow intact.
Our Take: Virto is a strong fit for European C&I engineers who want CAD control with real mounting data. The company is small, and documentation for advanced features lags the product.
Where It Falls Short
You need an AutoCAD or BricsCAD license and the skills to use it. Auto-stringing runs about 95% accurate and needs manual review. 3D rendering slows on large projects, and users ask for better tutorials. It produces engineering drawings, not stamped structural calculations.
Key Features
- Virto.CAD plugin for AutoCAD and BricsCAD
- Mounting manufacturer API integrations
- Virto.MAX browser tool for conceptual C&I design
- Automated string plans, 3D models, and BOM reports
Pricing
- Annual license: €2,980/year
- Monthly: €298/month; unlimited users on both MAX plans
Who Should Use Virto Solar
Strong fit: C&I engineering teams in Europe working in CAD with brand-specific racking. Probably not right for: Residential installers and teams without CAD licenses.
Quote From Real Engineering Data
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6. SurgePV — Best for 3D Rooftop Layouts That Feed Structural Review
Full disclosure: we build SurgePV. We ranked it #6 because it is not a structural calculation tool, and we will not pretend otherwise. What it does is produce the accurate 3D array geometry that every structural review starts from.
What It Does Well
Structural engineers waste hours redrawing layouts from sales PDFs. SurgePV’s 3D rooftop design gives them exact panel positions, setbacks, array dimensions, and a bill of materials from the start. The physics-based solar shadow analysis software places obstructions precisely, so the model the engineer reviews matches the roof the crew will see.
Because the whole platform is cloud-based, the structural reviewer opens the same project the designer built. No file exports, no version drift. String sizing, the module and inverter database, and the generation and financial model all read from the same layout. When the structural review forces a layout change, the production numbers and proposal update with it.
Our Take: SurgePV is the fastest way we know to hand a structural engineer a clean, measurable array layout. Pair it with a racking vendor tool or a PE for the load math.
Where It Falls Short
SurgePV does not calculate wind loads, snow loads, ballast, or pull-out resistance. There is no racking vendor catalog and no stamped output. For structural sign-off you need a racking configurator, a structural engineer, or both. There is also no native CRM, so project tracking happens elsewhere.
Key Features
- 3D rooftop design, layout, and string sizing
- Physics-based shadow analysis with obstruction modeling
- Energy yield plus payback, IRR, and NPV modeling
- Branded PDF proposals and Clara AI copy assistance
Pricing
- For 3 Users plan: $1,899/year — design, simulation, financials, and proposals included
- Free trial: Available with full design capabilities
Who Should Use SurgePV
Strong fit: Installers and EPCs who want one layout that serves design, structural review, and the customer proposal. Probably not right for: Teams needing stamped structural calculations inside the design tool.
7. PV*SOL Premium — Best for Rooftop Design with Mounting-System Integration
PV*SOL from Valentin Software has been in the market since 1998. The Premium edition adds detailed 3D design, and its mounting-system links give it a genuine structural angle.
What It Does Well
PVSOL Premium integrates directly with the K2 Base and Renusol PV-Configurator mounting planners. You design the array in PVSOL, then pass it to the racking tool for structural verification. That pairing covers rooftop projects from yield simulation through mounting statics in 2 affordable tools.
The 3D engine models module-by-module shading at hourly resolution, and the component database carries 21,000+ modules and 5,100+ inverters (Valentin Software, 2026). At €845 per year from the Valentin Software shop, it undercuts most engineering-grade rivals.
Our Take: For European rooftop work on a budget, PV*SOL plus K2 Base is the cheapest credible path from design to mounting verification. The Windows-only desktop format is the real cost.
Where It Falls Short
It runs on Windows only, with no cloud, no Mac, and no real-time collaboration. The 3D mode caps at 10,000 modules and slows past 7,000. Structural verification happens in the partner tools, not inside PV*SOL itself. Support runs on German business hours.
Key Features
- 3D design with module-level shading analysis
- K2 Base and Renusol mounting-system integration
- 21,000+ module and 5,100+ inverter database
- Reports in 24 languages
Pricing
- PV*SOL Premium 2026: €845/year plus VAT
- PV*SOL Standard: €585/year; students €90/year
- Free trial: 30 days, full features
Who Should Use PV*SOL Premium
Strong fit: Engineers and installers on complex European rooftops who pair yield work with mounting planning. Probably not right for: Mac teams, cloud workflows, and utility-scale projects.
8. IronRidge Design Assistant — Best Free Residential Racking Design
IronRidge Design Assistant is the racking manufacturer’s free web tool. For US residential structural design, it is the default starting point.
What It Does Well
The tool takes roof dimensions, module choice, and site conditions, then outputs a complete racking layout with attachment spacing. Its real value is the documentation: certification letters with site-specific wind and snow loads, referencing ASCE 7 load standards (IronRidge, 2026). Many AHJs accept these letters for residential permits without a separate engineering stamp.
Cost is $0. For an installer doing 30 residential roofs a month, the alternative is paying an engineer per project or risking permit rejection. The January 2026 Scanifly integration imports measured roof geometry directly, which removes transcription errors.
Our Take: If you install IronRidge hardware, there is no reason to design residential racking anywhere else. The certification letters alone justify learning the tool.
Where It Falls Short
It designs with IronRidge hardware only. Complex commercial rooftops and ground mounts exceed its scope. Load assumptions follow its own product span tables, so unusual structures still need an engineer. For context on the hardware choices involved, see our solar mounting structure guide.
Key Features
- Free racking layouts with attachment spacing
- Wind and snow load certification letters per ASCE 7
- Scanifly integration for measured roof import
- BOM generation for ordering
Pricing
- Design Assistant: $0 — free for all users
Who Should Use IronRidge Design Assistant
Strong fit: US residential installers using or open to IronRidge racking. Probably not right for: Multi-brand shops, commercial flat roofs, and ground mounts.
9. Unirac U-Builder — Best Free Racking Configurator for Commercial Rooftops
Unirac’s U-Builder is the free design tool for its racking line, spanning pitched roofs, flat roofs, and ground mounts. It covers a wider project range than most vendor tools.
What It Does Well
U-Builder handles the structural questions commercial rooftop projects raise: attachment spacing, ballast for flat roofs, and wind and snow load calculations tied to site conditions (Unirac, 2026). The output includes a full BOM and engineering reports the permit package can use.
The flat-roof ballast workflow deserves special mention. Ballast weight interacts with wind uplift, and getting it wrong either overloads the roof or under-secures the array. Our guide to flat roof ballast calculation explains the physics behind what U-Builder automates.
Our Take: U-Builder is the strongest free option once projects outgrow simple pitched roofs. As with every vendor tool, the calculations certify Unirac hardware only.
Where It Falls Short
The interface is functional rather than friendly, and new users report a learning curve on larger projects. Non-Unirac hardware is not an option. Stamped engineering still requires a PE where the AHJ demands one, and support response times vary by region.
Key Features
- Pitched roof, flat roof, and ground-mount racking design
- Ballast and attachment spacing with wind and snow loads
- Engineering reports and BOM output
- Free project sharing across teams
Pricing
- U-Builder: $0 — free for all users
Who Should Use Unirac U-Builder
Strong fit: Installers doing commercial flat roofs or ground mounts on Unirac hardware. Probably not right for: Vendor-neutral engineering teams and complex custom structures.
10. K2 Base — Best Free Mounting Planner for European Roofs
K2 Base from K2 Systems is the free planning tool behind much of Europe’s residential and small commercial racking design. It pairs directly with PV*SOL Premium.
What It Does Well
K2 Base runs static verification for K2 mounting systems against Eurocode 1 load standards with national annexes (K2 Systems, 2026). Snow zones, wind zones, and roof geometry produce a verified mounting plan with a structural report. For European installers, that report is the document building authorities expect.
The tool covers pitched, flat, and trapezoidal sheet metal roofs, and the PV*SOL integration means the yield model and the mounting plan stay consistent. Price is $0. For a related read on roof geometry, see our roof modeling software comparison.
Our Take: For European pitched-roof work, K2 Base plus PV*SOL is a complete design-to-statics workflow at under €850 per year total. It only certifies K2 hardware.
Where It Falls Short
Hardware lock-in is total. Large commercial and ground-mount projects exceed its scope. The interface assumes familiarity with European roof conventions, which slows non-EU users. Structural reports cover the mounting system, not the building itself; weak rafters remain your engineer’s problem.
Key Features
- Static verification per Eurocode 1 with national annexes
- Pitched, flat, and sheet metal roof coverage
- Direct PV*SOL Premium integration
- Structural reports and parts lists
Pricing
- K2 Base: $0 — free for all users
Who Should Use K2 Base
Strong fit: European residential and small commercial installers using K2 mounting systems. Probably not right for: US-market installers and large commercial or ground-mount projects.
How to Choose Solar Structural Design Software
Match the tool to the structural problem you actually have.
- Start with the mounting surface. Utility ground mounts need civil and grading tools (PVCase, RatedPower). Pitched residential roofs need racking vendor tools (IronRidge, K2 Base). Commercial flat roofs need ballast logic (Unirac, vendor tools).
- Fix your input data first. A structural design on wrong roof measurements is wrong, full stop. Drone surveys like Scanifly pay for themselves in avoided revisions.
- Know who stamps. Software calculates; licensed engineers certify. If you lack an in-house PE, tools with engineering services (PVComplete) or AHJ-accepted certification letters (IronRidge) matter more than modeling depth.
- Check the load standards. US projects need ASCE 7 references. European projects need Eurocode 1 with national annexes. A tool that cannot cite your code is a layout tool, not a structural tool.
- Count the handoffs. The layout your solar design software produces should feed the structural review without redrawing. Every manual transfer is an error waiting to happen.
- Price the hardware lock-in. Free vendor tools are excellent value, but only if you would spec that racking anyway.
Pro Tip
Take your last 3 permit rejections or revision requests and run them through any free vendor tool. If the tool’s documentation would have answered the AHJ’s objection, your structural workflow just got cheaper.
If you outsource structural or permit engineering, our team at Heaven Green Energy also runs a dedicated design consultancy. Their guide on how to choose a solar mounting structure covers the engineering side in more depth.
The Myth of the All-in-One Structural Tool
Here is the contrarian truth most software marketing avoids. No solar platform does structural design well as a side feature. The tools that claim “complete structural analysis” inside a sales-oriented platform usually mean a snow load lookup table and a disclaimer.
Real structural design splits into 3 jobs: accurate site geometry, load calculations tied to specific hardware, and a licensed engineer’s judgment. Different tools win each job. A drone survey tool, a racking configurator, and a PE stamp pipeline beat any single platform that promises all 3.
The other myth: free vendor tools are marketing toys. In our experience, IronRidge, Unirac, and K2 Base produce better-documented structural output than some paid platforms, because the vendor’s liability depends on the math being right. The trade is hardware lock-in, and for most installers that trade is worth it.
Conclusion
Structural design is where solar projects earn their permits and survive their first storm. The right stack depends on your segment: PVCase or RatedPower for utility-scale civil work, Scanifly for measured roof data, PVComplete for stamped plan sets, and the free racking vendor tools for the load calculations most AHJs actually ask for.
3 actions to take this week:
- Map your current handoffs. Count how many times array geometry gets redrawn between design, structural review, and permit. Every redraw is a fixable error source.
- Test 1 free vendor tool on a live project. IronRidge, Unirac, or K2 Base costs nothing and shows you exactly what documented structural output looks like.
- Standardize your survey data. Whether drone or manual, get roof measurements to a known accuracy before any structural work begins.
Want to see how SurgePV produces the 3D layouts and BOMs that feed a structural review? Book a 20-minute demo and we will walk through a real project.
Where SurgePV fits
For the product-side detail, structural drawings and CAD export covers the workflow, outputs and limits.
Frequently Asked Questions
What is solar structural design software?
Solar structural design software helps you plan how a PV array physically attaches to a roof or the ground. It covers racking selection, ballast, wind and snow loads, pull-out resistance, and the drawings a structural engineer or permit office needs to sign off.
Can solar design software replace a structural engineer?
No. Software generates load calculations, span tables, and certification letters, but most jurisdictions still require a licensed structural engineer to review and stamp the final design. Treat software output as an input to that review, not the deliverable itself.
What is the best free solar structural design software?
IronRidge Design Assistant, Unirac U-Builder, and K2 Base are all free. They produce wind and snow load calculations and stamped-ready documentation, but each one only works with that vendor’s own racking hardware.
How is structural design different from solar panel layout design?
Layout design decides where panels sit for maximum energy production. Structural design decides whether the roof or ground can safely carry them. The layout feeds the structural review; the structural review can force the layout to change.
What wind and snow loads should solar software handle?
In the US, software should apply ASCE 7 load combinations with site-specific wind speed and ground snow load. In Europe, it should follow Eurocode 1 with national annexes. Vendor tools like IronRidge and K2 Base automate this for their own racking.
Do I need structural software for residential solar?
Usually you need the racking vendor’s free tool plus a permit package. Dedicated structural software earns its cost on commercial flat roofs, carports, ground mounts, and any site with unusual loads or older buildings.
