User Guide

Everything you need to know about using SunTrace3D to analyze solar potential, simulate shadows, and estimate energy yield for any location worldwide.

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1

Getting Started

SunTrace3D is a browser-based 3D solar analysis tool. No installation, plugins, or sign-up is required to get started. Simply open the viewer and explore.

1

Open the Viewer

Click 'Open Viewer' from the home page. The default demo location (Pula, Croatia) loads automatically with a photorealistic 3D model.

2

Search a Location

Use the search bar in the header to find any address worldwide. The 3D model updates instantly when you select a new location.

3

Explore Shadows

Use the time slider at the bottom to see how shadows change throughout the day. Pick any date with the date picker.

SunTrace3D viewer overview showing 3D city model with shadows
The SunTrace3D viewer showing the 3D city model of Pula, Croatia with real-time shadow simulation
4

Shadow Simulation

SunTrace3D calculates accurate sun positions using the SunCalc library, which computes solar altitude and azimuth based on your location's latitude, longitude, date, and time. Shadows are cast in real-time using physically-based rendering.

Time Slider

Use the horizontal slider at the bottom of the viewer to scrub through 24 hours. Watch shadows sweep across buildings as the sun moves across the sky.

Date Picker

Select any date in the header to see how shadows change with the seasons. Compare summer solstice (longest day) with winter solstice (shortest day).

Understanding shadows

Shadow length and direction depend on the sun's altitude (height above the horizon) and azimuth (compass bearing). In the Northern Hemisphere, shadows point north at solar noon. Shadows are longest at sunrise and sunset, and shortest at solar noon. In winter, shadows are longer because the sun stays lower in the sky.

Shadow simulation showing building shadows at different times of day
Real-time shadow simulation — scrub through the day to see how shadows change across buildings
5

Sun Path Visualization

The sun path arc shows the complete trajectory of the sun across the sky for the selected date. A yellow/orange arc traces the sun's position from sunrise to sunset, with the current sun position highlighted.

What the sun path shows

Sun position marker
The bright yellow circle shows the current sun position in the sky
Sun arc
The curved line traces the sun's path from sunrise (east) to sunset (west)
Center marker
Blue pin marks the center of your selected location
Shadow direction
The directional light casts shadows opposite to the sun position
Sun path arc visualization across the sky
The sun path arc shows the complete trajectory of the sun for the selected date
6

Solar Panel Placement

Place virtual solar panels on any rooftop in the 3D model. SunTrace3D calculates irradiance based on panel tilt, azimuth, and shading from surrounding buildings.

How to place solar panels

  1. 1
    Activate panel mode
    Click the solar panel button in the toolbar (bottom-left). This activates the panel placement mode.
  2. 2
    Click on a rooftop
    Click anywhere on a rooftop surface. A virtual solar panel appears at the clicked location.
  3. 3
    Configure panel properties
    Use the sidebar panel to adjust the panel's tilt angle, azimuth, area, and efficiency. Default values are set for typical residential installations.
  4. 4
    View energy estimates
    The solar dashboard automatically calculates annual energy yield based on your panel configuration and location using PVGIS satellite irradiance data.
Virtual solar panels placed on a rooftop with energy calculations
Place virtual solar panels on rooftops and see real-time energy yield calculations
7

Energy Yield Analysis

SunTrace3D estimates annual energy yield using the PVGIS (Photovoltaic Geographical Information System) database maintained by the European Commission. PVGIS provides satellite-based solar irradiance data for locations worldwide.

What's calculated

  • Annual energy yield in kWh
  • Peak power output in kW
  • Specific yield (kWh/kWp)
  • Monthly energy production breakdown
  • Shading loss factor
  • System losses (inverter, wiring)

Input parameters

  • Panel tilt angle (0° – 90°)
  • Panel azimuth (compass direction)
  • Total panel area (m²)
  • Panel efficiency (typically 18-22%)
  • Location coordinates (automatic)
  • Local solar irradiance data (PVGIS)

About PVGIS data

PVGIS uses satellite imagery and meteorological data to provide solar irradiance values averaged over many years. The data accounts for typical weather patterns, cloud cover, and atmospheric conditions. System losses of 14% are applied by default to account for inverter efficiency, wiring losses, and temperature effects.

Energy yield dashboard showing annual kWh estimates and monthly breakdown
The energy yield dashboard shows annual production estimates and monthly breakdown charts
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SD & HD Quality Modes

SunTrace3D offers two quality levels for 3D models. The quality badge in the viewer toolbar shows the current mode.

SD

Standard Detail

Available on the free tier. Models load instantly via Google 3D Tiles streaming with moderate geometric and texture detail (LOD4, errorTarget=24). Perfect for quick shadow studies and solar analysis.

Free — no account required

HD

High Definition

Available on the Pro tier. Photorealistic models with maximum texture and geometric detail (LOD6, errorTarget=6). Individual building features, vegetation, and street-level detail are clearly visible.

Pro subscription — $9/month

Side-by-side comparison of SD and HD model quality
SD vs HD quality comparison — HD models show significantly more texture and geometric detail
9

Compass & Orientation

The compass overlay in the viewer shows true north orientation relative to your current camera angle. This is essential for understanding shadow directions and optimal solar panel orientation.

Reading the compass

  • The compass rotates as you orbit the 3D model, always pointing toward true north
  • In the Northern Hemisphere, south-facing panels receive the most sunlight
  • Use the compass to verify panel azimuth when placing solar panels
Compass overlay showing north direction in the 3D viewer
The compass overlay rotates with the camera to always indicate true north
10

Account & Subscription

SunTrace3D works without an account for basic shadow simulation and solar analysis. Create a free account to save your work, or upgrade to Pro for HD models and API access.

Account features

Free account

  • Save and load projects
  • SD quality models
  • Full shadow simulation
  • Solar panel analysis

Pro subscription ($9/mo)

  • HD photorealistic models
  • Partner API access
  • Embeddable 3D viewer
  • Priority support

Managing your subscription

Subscriptions are managed through Stripe. Click the user menu in the viewer header to access your account settings and subscription portal. You can upgrade, downgrade, or cancel at any time.

Building an integration?

Check out the API documentation for generating models programmatically and embedding 3D views on your website.

API Documentation