SOLARDESIGNTOOL

This software available online allows to create PV system designs and accurate panel layouts.
Generate customer design options in minutes, complete with PDF system datasheet, including data from electrical specifications to array layout diagrams.
The SolarCAD feature help to define the Installation area for the solar project only in a few minutes : accurate dimensions, unlimited obstructions, define setbacks, rows, orientation.
The array layout engine quickly determines the most optimal panel layout for the installation area to maximize its solar potential.
The web-based Solar Electric Design platform replaces countless hours of monotonous calculator-and-pen guesswork, with a streamlined user interface that creates optimal systems based on particular requirements.
There is a free version for one month (but you have to give your credit card number), and an expert version with a monthly fee (from 50 USD/month).
SolarDesignTool