What Is Skelion?
Skelion is a solar design plugin for SketchUp that transforms Trimble’s popular 3D modeling application into a capable photovoltaic (PV) system design tool. Developed by Spanish engineers Sam Jankis and Juan Pons, Skelion was first released in 2011 and has grown into one of the most widely used solar-specific SketchUp extensions in the world.
The core problem Skelion solves: SketchUp by itself is a general-purpose 3D modeler with no solar-specific functionality. Placing solar panels manually, calculating sun angles, performing shading analysis, and generating energy yield estimates all require either hours of manual work or separate specialized software. Skelion automates the solar-specific parts of this workflow — inserting panels automatically on any surface, calculating shading, integrating with energy simulation APIs, and generating client-ready reports — all from within the familiar SketchUp environment.
Current version: 5.5.3
Compatibility: Windows and macOS
SketchUp compatibility: SketchUp Pro (required for plugin installation)
Skelion is used by:
- Solar PV designers and engineers at installation companies
- Architects integrating building-integrated photovoltaics (BIPV) into designs
- EPC contractors designing rooftop and ground-mount solar systems
- Energy consultants creating preliminary designs for client proposals
- Students and trainees learning solar system design
- Engineers requiring quick preliminary layouts before detailed simulation
Free vs Pro — What’s the Difference?
Skelion offers two tiers:
Skelion Free
The free version provides the core functionality that made Skelion popular — automatic solar panel insertion:
- Automatic panel insertion on any planar SketchUp surface
- Selection of panel orientation (portrait or landscape)
- Basic sun position calculation — azimuth and tilt angle for any location and time
- Access to the built-in PV module database
- Custom 3D component creation and import
- Compatible with both Windows and macOS
For users who only need to generate visual layouts without energy analysis, the free version is fully functional.
Skelion Pro (~$133/year)
The professional version adds the analytical and reporting capabilities required for real project proposals:
- All Free features, plus:
- Shadow projection and shading analysis — visualize shading from obstructions at any hour of the year
- Energy and power ratio calculations — estimate system performance metrics
- Irregular surface panel insertion — place panels on non-planar, curved, or mesh surfaces
- PVGIS integration — automatic energy yield reports using EU satellite irradiance data (for installations in Europe, Africa, and Asia)
- PVWatts integration — automatic energy yield reports using NREL data (for US installations)
- SAM (System Advisor Model) integration — export to NREL’s SAM for detailed financial and performance analysis
- PVsyst export — export 3D model and panel layout to PVsyst for bankable energy simulation
- Solar tracker simulation — model and animate single-axis and dual-axis solar tracking systems
- Backtracking calculation — calculate optimal backtracking angles for single-axis trackers to minimize inter-row shading losses
- Ground-mount terrain adaptation — align panel rows to 3D mesh terrain surfaces
- Bifacial module support — model bifacial PV modules with rear-side irradiance contribution
- Financial estimates — ROI, payback period, and CO2 savings for client presentations
- Customizable PV module database — add proprietary or branded modules with custom dimensions and specifications
For any professional project requiring deliverable energy reports or shading analysis documentation, Skelion Pro is the required tier.
Core Features In Detail
Automatic Panel Insertion
The flagship feature that defines Skelion’s productivity value. The workflow:
- In SketchUp, select a surface (roof face, ground plane, or other planar surface)
- Click the Skelion solar cell icon in the toolbar
- Configure panel parameters:
- Panel type — select from database or custom
- Tilt angle — angle of panel relative to the surface
- Azimuth — compass direction the panels face
- Row spacing — gap between rows for maintenance access and shading avoidance
- Orientation — portrait or landscape
- Click insert — Skelion automatically fills the selected surface with solar panels, respecting the configured spacing and alignment
What makes this powerful: Skelion handles the geometry calculations — it correctly calculates how many panels fit, accounts for row spacing, aligns panels to the roof edge, and handles irregular roof shapes (L-shaped roofs, roofs with dormers or obstructions). A layout that would take 30–60 minutes of manual SketchUp work is completed in seconds.
Irregular surfaces (Pro): Skelion Pro can insert panels on curved or mesh surfaces — useful for BIPV applications, curved carport canopies, or ground-mount sites with terrain variation.
Shading Analysis (Pro)
Once panels are placed, Skelion Pro analyzes shading from any obstructions in the 3D model:
- Obstruction projection — Skelion projects the shadow that chimneys, parapets, neighboring buildings, trees, and other 3D objects cast over the panel array
- Time-based shading — calculate shading at any hour of any day of the year for the project location
- Two shading criteria — identify which panels fall within shading-affected zones based on configurable acceptance criteria (e.g., panels with more than X% of area shaded at a specific critical time are excluded)
- Visual display — shaded areas highlighted directly on the 3D model for intuitive review
This shading analysis drives layout optimization — move panel rows, adjust setbacks, or reconfigure the array to minimize shading losses before finalizing the design.
Energy Reports — PVGIS and PVWatts Integration (Pro)
Skelion Pro connects directly to external energy databases to generate yield estimates:
PVGIS (Photovoltaic Geographical Information System):
- EU JRC satellite-derived irradiance database covering Europe, Africa, and most of Asia
- Free API access — no account needed
- Provides TMY (Typical Meteorological Year) data for any coordinate
- Skelion sends the system parameters (location, tilt, azimuth, system size) and receives monthly and annual energy yield estimates
- Generates a formatted energy report automatically
PVWatts:
- NREL’s (US National Renewable Energy Laboratory) irradiance database
- Best coverage for US and North America locations
- Same automated workflow: Skelion sends parameters, receives yield estimates, generates report
Practical use: After completing the panel layout, the designer enters the location (or loads from Google Earth), selects the energy database, and runs the energy report with one click. The resulting report shows monthly and annual energy production, system performance ratio, and capacity factor — sufficient for preliminary proposals and feasibility studies.
PVsyst Export (Pro)
For projects requiring bankable energy reports — utility-scale systems, projects requiring project finance, or any installation where lenders or investors review the yield estimate — PVGIS and PVWatts provide preliminary guidance, but PVsyst is the industry standard for final simulation.
Skelion Pro’s PVsyst export bridges this gap:
- Export the 3D panel layout and shading scene from Skelion/SketchUp directly into PVsyst
- The shading geometry (3D obstruction models) transfers to PVsyst’s horizon and near-shading analysis
- Engineers avoid duplicating the shading model in PVsyst’s separate 3D environment
- Workflow: Skelion for 3D layout and visual presentation → PVsyst for bankable simulation
This SketchUp + Skelion → PVsyst workflow is a common pattern among solar EPCs who need both client-facing 3D visuals and rigorous energy analysis.
Solar Tracker Simulation (Pro)
For ground-mount projects using tracking systems:
- Single-axis tracker (SAT) — simulate panel rotation around a horizontal N-S axis, following the sun’s daily east-to-west movement
- Dual-axis tracker — simulate panels tracking both daily and seasonal sun movement
- Animation — animate the tracker movement in SketchUp for client presentations
- Backtracking — calculate optimal SAT rotation angles for backtracking mode (panels angle slightly away from optimal tracking to prevent inter-row shading in low sun angle conditions)
- Backtracking losses — quantify the energy yield impact of backtracking vs. no-backtracking configurations
For utility-scale ground-mount projects where tracking systems represent significant capital expenditure, the ability to visualize and model tracker behavior in 3D within the same layout tool saves significant design time.
Google Earth / Maps Integration
Skelion links SketchUp’s georeferencing with external mapping:
- Load the project location from Google Earth — the SketchUp model inherits the real-world geographic coordinates and north orientation
- Skelion uses the loaded coordinates for accurate sun path calculations — azimuth and elevation angles are computed for the actual site location and time zone
- Google Maps integration for satellite imagery overlay during layout
This eliminates manual coordinate entry and ensures all sun angle and energy calculations reflect the actual project location.
Custom PV Module Database
Both Free and Pro versions allow database customization:
- Browse and select from the built-in database of commercial PV modules
- Add custom modules — enter manufacturer, model, physical dimensions, and electrical specifications
- Create custom 3D components for non-standard panel formats (BIPV modules, frameless glass, thin-film modules)
- Company-specific databases for EPC contractors working with preferred panel suppliers
Financial and Environmental Estimates (Pro)
For preliminary client proposals, Skelion Pro generates basic financial metrics:
- ROI (Return on Investment) calculation
- Payback period estimate
- CO2 savings — estimated lifetime carbon dioxide emissions avoided
- These estimates support first-pass feasibility conversations with clients before commissioning detailed analysis
Typical Workflow: Residential Rooftop System
Step 1 — Model or Import the Building Either create a SketchUp model of the building from scratch, import from an architect’s SketchUp file, or use SketchUp’s built-in Google Earth import to create a basic building model from satellite imagery.
Step 2 — Geolocate Load the project location from Google Earth or manually enter latitude/longitude. This sets up accurate sun position calculations.
Step 3 — Add Obstructions Model any roof obstructions — chimneys, vents, skylights, HVAC equipment, parapet walls — as 3D SketchUp objects. These will be used for shading analysis.
Step 4 — Insert Panels Select the usable roof surface, open Skelion, configure panel parameters (type, tilt, azimuth, row spacing), and click insert. Panels populate the roof automatically.
Step 5 — Run Shading Analysis (Pro) Run Skelion’s shading projection for the critical period (typically the winter solstice at noon or a project-specific worst-case scenario). Identify shaded areas and remove or relocate panels accordingly.
Step 6 — Generate Energy Report (Pro) Select PVGIS or PVWatts, confirm the system parameters (DC capacity, inverter efficiency, system losses), and generate the energy yield report.
Step 7 — Create Proposal Export rendered images of the 3D model with panels — use SketchUp’s built-in rendering or connect with rendering extensions like V-Ray. Combine the 3D visuals with the Skelion energy report into a client proposal.
Total time for a typical residential rooftop: 30–90 minutes vs. 4–8 hours using manual methods.
Skelion vs. Other Solar Design Approaches
| Approach | Skelion + SketchUp | Aurora Solar | HelioScope | PVcase + AutoCAD |
|---|---|---|---|---|
| 3D modeling quality | ✅ Excellent | ✅ Good (satellite) | ✅ Good (satellite) | ✅ Excellent |
| Automatic panel placement | ✅ | ✅ | ✅ | ✅ |
| Shading analysis | ✅ Pro | ✅ | ✅ | ✅ |
| PVGIS / PVWatts integration | ✅ | ✅ | ✅ | Limited |
| PVsyst export | ✅ Pro | ❌ | ❌ | ✅ |
| Solar tracker modeling | ✅ Pro | Limited | ✅ | ✅ |
| Ground-mount terrain adaptation | ✅ Pro | Limited | ✅ | ✅ |
| Bankable energy reports | ❌ (needs PVsyst) | Limited | Limited | ❌ (needs PVsyst) |
| Electrical design (SLD) | ❌ | ✅ | ✅ | Limited |
| Proposal generation | ✅ (via SketchUp) | ✅ | ✅ | Limited |
| Platform | SketchUp plugin | Web | Web | AutoCAD plugin |
| Mac support | ✅ | ✅ | ✅ | Limited |
| Price (Pro) | ~$133/year | Higher | Higher | Higher |
| Learning curve | Moderate (needs SketchUp) | Low-moderate | Low | Moderate |
Skelion’s strongest position: Teams already fluent in SketchUp who need to add solar design capability quickly and cost-effectively. The combination of SketchUp’s modeling flexibility, Skelion’s solar automation, and PVsyst export for bankable simulation creates a workflow that’s hard to beat for 3D presentation quality at reasonable cost.
Where dedicated platforms win: High-volume proposal generation, integrated electrical design (SLD generation, wire sizing), and teams without existing SketchUp expertise.
Installation Guide
Prerequisites
- Trimble SketchUp Pro (free version does not support third-party plugin installation)
- Windows 10/11 or macOS 10.15+
- Internet connection for PVGIS/PVWatts integration and license activation
Installation Steps
Method 1 — SketchUp Extension Warehouse (Recommended)
- Open SketchUp Pro
- Go to Window → Extension Warehouse
- Search for “Skelion”
- Click Install
- Accept the license agreement
- Restart SketchUp
- Activate the Skelion toolbar: View → Toolbars → Skelion
Method 2 — Manual RBZ Installation
- Download the Skelion .rbz file from skelion.com
- In SketchUp: Window → Preferences → Extensions → Install Extension
- Select the downloaded .rbz file
- Restart SketchUp
License Activation (Pro)
After installation, enter the Pro license key in the Skelion menu → License. The activation requires internet connection to verify the license against Skelion’s servers.
Frequently Asked Questions
Does Skelion work with SketchUp Free (web version)? No. The SketchUp free web version does not support third-party plugins. Skelion requires SketchUp Pro (desktop application).
Can Skelion place panels on curved or irregular roofs? The free version supports only planar (flat) surfaces. Skelion Pro supports irregular surfaces including curved roofs and 3D mesh terrain — panels are distributed across the mesh surface following the contour.
How accurate are the PVGIS and PVWatts energy estimates from Skelion? They are suitable for preliminary feasibility and client proposals. The accuracy is comparable to using PVGIS or PVWatts directly — the quality of the result depends on the accuracy of the system parameters entered (losses, inverter efficiency, etc.). For project finance or bankable reports, export to PVsyst for detailed simulation.
Does Skelion support thermal solar collectors (solar water heating) as well as PV? Yes. Skelion supports insertion of both PV panels and solar thermal components — flat plate collectors and evacuated tube collectors. Thermal systems can be included in the same 3D model alongside PV arrays.
Can I model bifacial PV panels in Skelion? Yes. Skelion Pro supports bifacial module modeling with configurable bifaciality factor and ground albedo for estimating rear-side energy contribution.
Is Skelion compatible with SketchUp 2024/2025? Compatibility with current SketchUp versions is maintained through the Extension Warehouse. Always download the latest version from the Extension Warehouse or skelion.com to ensure compatibility with your SketchUp version.
Summary
Skelion is the most practical solar design plugin available for SketchUp users — turning the world’s most accessible 3D modeling tool into a capable solar layout, shading analysis, and preliminary energy reporting platform. For architects, solar designers, and engineers already working in SketchUp, it adds solar capability at low cost (~$133/year for Pro) without switching to a dedicated platform.
The combination of Skelion’s automatic panel placement and shading tools with a clean PVsyst export path gives professional solar designers a workflow that delivers both client-friendly 3D visuals and a clear route to bankable energy simulation — making it a compelling tool for firms handling both residential and ground-mount commercial solar projects.
For licensing assistance or questions about Skelion, contact our team via Telegram: t.me/DoCrackMe
Related articles: PVsyst 8 — Bankable Energy Simulation Guide | PV*SOL Premium 2026 — Solar Design and Simulation Guide | PVcase Ground Mount — AutoCAD-Based Utility Solar Design
