ANT

• Introduction
• Installation
• Version
• Support Forum
• Tutorials
• Example cases

Introduction

ANT is a multizone indoor air quality (IAQ) and ventilation analysis plug-in on Rhino Grasshopper. ANT integrates the functions of programs in CONTAM family, including CONTAMW, CONTAM Weather File Creator, CONTAM Particle Distribution Calculator, FaTIMA, CONTAM Results Viewer, and CONTAM Results Export Tool, which allows ANT to perform analyses of

• multizone airflow and contaminant transport,
• occupant exposure to indoor contaminants,
• estimation of transmission and infection risk of respiratory diseases, and
• visualization of contaminant and exposure modelings.

CONTAM is a program (family) developed by NIST to accomplish multizone IAQ and ventilation analyses. ContamP and ContamX APIs were used in ANT to develop GH components to create CONTAM project elements (such as zones, paths, air handling system, and occupancy), generate project files (.prj) and run simulations. The original CONTAM and associated tools can be found on NIST website and a Python wrapper for ContamX (CONTAM simulation engine) is available on PyPI.

The name "ANT" originates from "contaminant" (or "contam-in-ant"). It implies the link between CONTAM and ANT, but also embodies the mission of ANT. Besides the regular functions of CONTAM, the highlighted features of ANT mainly include

• capability of establishing straightforward and realistic 3D building/room models for CONTAM analyses (compared to the conventional way of drawing 2D models on the sketchpad within CONTAMW),
• simplified approaches on creating CONTAM zones and paths,
• logistic and intuitive connections among components,
• access to U.S. EPA's Air Quality System (AQS) database to generate ambient contaminant files (.ctm) for typical atmospheric contaminants in U.S. cities,
• estimation of contaminant exposures and disability-adjusted life years (DALYs),
• calculation of multizone airborne transmission and infection estimation for respiratory diseases (e.g. COVID-19), and
• visualization of contaminant and exposure calculations through plots, contours, and animations.

Installation

1. Download and unzip ANT from Food4Rhino
2. Place the entire ANT folder (including .gha and other dependencies) under Grasshopper's Components Folder (via Grasshopper - File - Special Folders). (In Windows, the Components Folder is located under "%Appdata%\Roaming\Grasshopper\Libraries")
3. Unblock files in ANT folder
   • Manually unblock all files
     • Right click on the files in ANT folder and select "Properties"
     • Check "Unblock" under "General" tab (or "Security" tab)
     • Click "Apply" or "OK"
   • Or, unblock all files using PowerShell (recommended)
     • Open PowerShell as administrator
     • Run the following command (replace "path_to_ANT_folder" with the actual path to ANT folder)

     Get-ChildItem -Path "path_to_ANT_folder" -Recurse | Unblock-File

4. Restart Rhino/Grasshopper and enjoy.

Version

The latest version of ANT is 0.2.6. The version number of ANT is aligned with the 3.5 version of CONTAM APIs and simulation engine (contamx3.exe). The revision history of ANT is provided in ANT Revision History.

Support Forum

• Google Group of ANT

Tutorials

0 - Introduction to ANT components and CONTAM elements

1 - Basic settings and creating zones

Example cases

Example cases only compatible with the latest version of ANT. Please check the latest version of ANT from Food4Rhino.

Example 1 - A simple house

Building geometry in Rhino

ANT model in Grasshopper

Visualization of simulation results

Contours of contaminant concentrations

Animation of contaminant concentration change

Plot of contaminant concentrations in different zones

Example 2 - DOE prototype medium office