---
name: "g2root"
section: "1"
platform: "linux"
package: "root"
version: "6.40.04-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/g2root"
---

# g2root(1)

convert GEANT geometry files to ROOT files

## NAME

g2root - convert GEANT geometry files to ROOT files

## SYNOPSIS

**g2rootd** *\[-f map\_name\] geant\_name macro\_name*

## DESCRIPTION

You can convert a **GEANT** (see *http://geant.cern.ch/* fore more on **GEANT**) geometry to **ROOT** geometry with the following steps

- 1

  Run the interactive version of **GEANT** and produce a Zebra RZ file *detector.geom*, by typing the command:

  Geant \> rz/file 21 *detector.geom* on

- 2

  Run the **g2root** program to convert the Zebra RZ file into a **ROOT** macro *detector.C:*

  g2root *detector.geom* *detector.C*

- 3

  Run the following **ROOT** session;

  ```
  root [1] .x detector.C
  root [2] detector.Draw()
  root [3] c1.x3d()   // (this invokes the 3-d Root viewer)
  root [4] TFile f("detector.root","NEW") //open a new root file
  root [5] detector.Write() //Write the geometry structure
  root [6] f.Write()
  ```

  Note that the *TNode* structure currently in **ROOT** was not designed as a replacement for a true geometry package. The idea was mainly to draw simple geometries in event display programs. We are currently investigating several alternatives for a true & efficient geometry package supporting;

- \-

  a disk data base with storage of multiple geometry versions

- \-

  an interactive editor and viewer

- \-

  with 3-d views

- \-

  but also 2-d cut views

- \-

  with interfaces to existing or future MC such as **GEANT3** or **GEANT4**

A second program called **gh2root** (see *http://root.cern/root/gh2root.html*) generates automatically C++ code corresponding to the **GEANT3 Zebra** structures *JSET*, *JVERTX*, *JKINE*, *JHITS* and *JDIGI.*

## SEE ALSO

*[root(1)](/root/1.md)*, *[h2root(1)](/h2root/1.md)*,

and

*The ROOT Users Guide*

available from the main **ROOT** website:

*http://root.cern*

## ORIGINAL AUTHORS

The ROOT team (see web page above):

**Rene Brun** and **Fons Rademakers**

## COPYRIGHT

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

## AUTHOR

This manual page was written by Christian Holm Christensen \<cholm@nbi.dk\>, for the Debian GNU/Linux system (but may be used by others).