Wire-based gaseous detectors (e.g. multi-wire proportional chambers, drift chambers, drift tubes, cathode strip chambers, time projection chambers with wire readout) are precisely simulated since the early 1990s with Garfield, developed by Rob Veenhof.

Garfield++ is a toolkit for the detailed simulation of particle detectors based on ionisation measurement in gases or semiconductors. The main area of application is currently in micropattern gaseous detectors.

Garfield++ shares functionality with Garfield. The main differences are the more up-to-date treatment of electron transport in gases and the user interface, which is derived from ROOT.

Garfield++ can calculate very efficiently analytically the electric field for 2D geometries using complex algebra. Interfaces are available for HEED which is used for the simulation of the primary ionization of charged particles and Magboltz for the transport parameters of electrons. Primary ionization due to electrons and heavy ions can be calculated using Degrad and SRIM, respectively, and can be imported into Garfield++. The induced charges on all electrodes in the device are evaluated using weighting fields and convoluted with nearly arbitrary transfer functions to simulate the signals. Wire-based gaseous detectors can be modelled very well in two dimensions, and the availability of the Garfield++ simulation has led to wire chambers being the gaseous detectors whose physics is most deeply understood and well simulated. For TPCs, the Garfield software suite has been used to evaluate the performance of the amplifying readout detectors as well as to study, identify and select the ideal gas mixture and electric field by investigating deeply their main transport properties (drift velocity and longitudinal and transverse diffusion).