What is Ladybug Tools?

Ladybug Tools is a collection of free computer applications that support environmental design and education.
Of all the available environmental design software packages, Ladybug Tools is among the most comprehensive, connecting 3D Computer-Aided Design (CAD) interfaces to a host of validated simulation engines.


Ladybug Tools is built on top of several validated simulation engines: Radiance, EnergyPlus/ OpenStudio, Therm/ Window and OpenFOAM.

Free + Open Source

Ladybug Tools is the only open source interface that unites all of its underlying open source engines. Like these engines, it evolves through the consensus of an open community of experts.


Ladybug Tools is supported by a passionate and diverse community from around the world. Visit our online forum to see the discussions that shape our future development.

500k+ Downloads

Ladybug Tools has been downloaded more than 500,000 times and is the 3rd most downloaded plugin for Grasshopper.


Ladybug Tools runs within 3D modeling software and allows data transfer between its simulation engines. So all geometry creation, simulation, and visualization happen within one interface.


Ladybug Tools is composed of modular components, making it flexible across different stages of design and capable of answering a variety of research questions.


Ladybug Tools runs within parametric visual scripting interfaces, enabling the exploration of design spaces and the automation of tasks.


By harnessing capabilities of CAD interfaces, Ladybug Tools produces a variety of interactive 3D graphics, animations, and data visualizations.


Ladybug Tools is written in Python, which can be run on virtually any operating system and plugged into any geometry engine (provided the geometry library is translated).


We are the developers of Ladybug, Honeybee, Butterfly, Dragonfly, and EPWMap
We also contribute to open-source projects including Design Explorer and the Glazing + Winter Comfort Tool.


Browse the features of each application using the web of interoperability below.
Double click an image to read more. Press Ctrl + Click to pan. Press Ctrl + Scroll to zoom.

Who is using Ladybug Tools?

Ladybug Tools is used by architects, engineers, consultants, simulation experts, and academics alike.
Here is a short list of the offices and schools using our applications.