CAD-to-PV Mapping

CAD-to-PV Mapping is the process of converting architectural or engineering CAD drawings into functional solar PV system designs. It bridges the gap between building plans (DWG/DXF files, as-built drawings, structural layouts) and solar design software, allowing designers to accurately position modules, define boundaries, apply setbacks, assess obstructions, and generate compliant electrical layouts directly from CAD-based geometry.

This workflow is essential for commercial, industrial, and utility-scale projects where precise structural details, roof penetrations, mechanical equipment, and load-bearing zones must be considered. CAD-to-PV Mapping ensures solar designs are structurally aligned, code-compliant, and construction-ready, especially when integrated with platforms like Solar Designing and shading tools such as Shadow Analysis.

Key Takeaways

CAD-to-PV Mapping converts CAD drawings into usable solar design geometry.
Essential for commercial, industrial, and utility-scale accuracy.
Supports auto-layout, obstruction detection, and electrical design workflows.
Saves significant design time and improves compliance with AHJ and NEC rules.
Works seamlessly with tools like Auto-Design, Shadow Analysis, and Solar Designing.

What Is CAD-to-PV Mapping?

CAD-to-PV Mapping is the transformation of CAD geometry—lines, layers, blocks, polylines, roof outlines, mechanical layouts—into solar design surfaces and installation zones. It allows high-fidelity building models to be used during PV system layout, rather than relying solely on satellite imagery or manual tracing.

This process enables designers to:

Import CAD roof plans and site drawings
Extract roof edges, pitches, ridges, and hip lines
Identify obstructions (skylights, HVAC units, vents)
Convert polylines into array boundaries
Apply fire setbacks and AHJ rules
Generate optimized module layouts using Auto-Design
Produce precise stringing and electrical mapping

Related concepts include Array Boundary Tool, Solar Layout Optimization, and 3D Solar Modeling.

How CAD-to-PV Mapping Works

Although software tools differ, the typical workflow includes:

1. Import CAD Files

Users upload DWG, DXF, or IFC files containing building geometry, mechanical layouts, roof plans, or site plans.

2. Identify Relevant Layers

Designers select the CAD layers for:

Roof edges
Parapets
Obstructions
Walkways
Structural elements

These are converted into usable PV design elements.

3. Convert Lines to Boundaries

Polylines become installation boundaries using tools like the Array Boundary Tool.

4. Apply Setbacks & Compliance Rules

Software automatically enforces:

AHJ fire setbacks
Access pathways
NEC 690 requirements
Structural buffer zones

For jurisdiction-specific rules, see AHJ Compliance.

5. Auto-Generate Module Layout

Using Auto-Design, the software places modules within the boundaries.

6. Map Strings & Electrical Paths

The design engine produces string groups and electrical connections per:

Voltage limits
Current limits
Inverter configurations

See Stringing & Electrical Design.

7. Validate with Shading Analysis

Designs are evaluated for potential shading conflicts using Shadow Analysis.

Types / Variants of CAD-to-PV Mapping

1. Rooftop CAD Mapping

Used for commercial roofs where mechanical equipment and structural zones are detailed in CAD.

2. Ground-Mount CAD Mapping

Converts civil engineering drawings—lot boundaries, grading contours, roads—into PV installation surfaces.

3. Carport/Canopy CAD Mapping

Uses structural CAD drawings to place modules precisely on canopy beams and frames.

4. IFC/BIM-to-PV Mapping

Imports BIM models from architects or structural engineers for high-fidelity PV placement.

5. Automated CAD Layer Detection

AI identifies layers such as obstructions, setbacks, and roof boundaries without manual sorting.

How CAD-to-PV Mapping Is Measured

Geometric Accuracy

Precision between CAD surfaces and exported PV layout.

Module Fit Efficiency

How effectively the mapped boundaries are utilized by the PV layout.

Obstruction Accuracy

How accurately HVAC units, skylights, vents, or chimneys are captured from CAD.

Engineering Compliance

Ensures alignment with AHJ and NEC constraints.

Time Savings

Reduces manual tracing time by 70–90% on C&I projects.

Typical Values / Ranges

Most designers save 2–5 hours per project when CAD-to-PV Mapping is leveraged.

Practical Guidance for Designers & Installers

1. Request CAD Files Early

Ask architects or facility managers for updated DWG/DXF drawings.

2. Use Clean Layer Management

Remove unnecessary CAD layers before importing to reduce noise.

3. Apply Accurate Setbacks

Use CAD edges with AHJ rules to maintain compliance—see AHJ Compliance.

4. Validate CAD Geometry Against Reality

Use drone images or site photos to confirm CAD accuracy.

5. Combine Mapping With Shading Tools

Pair boundaries with Shadow Analysis to avoid shading losses.

6. Use Auto-Design for Efficient Layout

Once mapped, run Auto-Design to generate optimized layouts.

7. Coordinate with Structural Engineers

Especially important for penetrations, equipment loads, and walkway requirements.

8. Prepare for Permitting

Mapped CAD geometry streamlines permit pack creation through the Solar Project Planning Hub.

Real-World Examples

1. Commercial Flat Roof

A designer imports a CAD file showing rooftop HVAC units. CAD-to-PV Mapping converts mechanical zones into “no-build” areas, producing a 420 kW layout that avoids structural conflicts.

2. Industrial Warehouse

Structural CAD drawings reveal load-restricted roof zones. The mapping tool excludes those areas automatically, ensuring a code-safe 300 kW design.

3. Ground-Mount Solar Site

Civil site CAD files containing property boundaries and grading contours are imported. The mapping tool creates array zones that avoid setback lines and slopes.