Nanotube Builder
****************

The Nanotube Builder allows you to construct a single-walled nanotube
using the Atomic Simulation Environment (ASE).

See also:

  * ASE: Atomic Simulation Environment

  * ASE build module: Nanotubes


How to use the nanotube builder
===============================

The nanotube builder creates a **single-walled nanotube** defined by
the standard roll-up vector notation **(n, m)** and a **length** given
as the number of axial repetitions.

1. **Choose the element and bond length (optional)** By default, the
   nanotube is built from carbon. You may choose a different
   **element** and specify a **bond length**.

2. **Choose the periodic direction** Select whether the nanotube axis
   is along **x**, **y**, or **z**. The builder will align the
   nanotube with the selected direction and set the lattice
   accordingly.

   Note:

     For 1D periodic calculations (a *chain*) AMS uses the **x**
     direction as the periodic direction. If you choose **y** or
     **z**, you may need to rotate the system or adjust settings
     depending on the engine and workflow you plan to use.

3. **Set the vacuum** Specify the **vacuum** around the nanotube. This
   determines the lattice vectors perpendicular to the nanotube axis.

4. **Set the roll-up vector and length** Specify the roll-up vector
   **(n, m)** and the nanotube **length** (axial repetitions).

5. **Generate the nanotube** Click **Generate Nanotube** to create the
   structure. Use **Close** to accept the result and close the
   builder, or **Cancel** to discard changes.

After generating a nanotube, information about the result is displayed
in the message area below the visualization. The lattice vectors are
updated, and the builder generates bonds using AMSinput’s bond-
guessing functionality.

If the current engine supports it, the periodicity will switch to **3
(Bulk)**.


Dry run
=======

Enable **Dry run** to generate and save the Python script without
running it. The script can serve as a starting point for running the
Nanotube Builder from Python, or for inspecting the parameters and
process used to create the nanotube.
