user16403: Atmel stated in their website:

Atmel Studio 7 features seamless one-click import of projects created in the Arduino development environment. Your sketch, including any libraries it references, will be imported into Studio 7 as a C++ project. Once imported, you can leverage the full capabilities of Studio 7 to fine-tune and debug your design. Atmel Studio 7 fully supports the powerful embedded debugger on the Arduino Zero board. For other Arduino boards, shield-adapters that expose debug connectors are available, or switch to one of the many available Xplained-Mini/PRO boards to fully leverage the Atmel HW eco-system. Regardless of what you choose, you will surely make something amazing.

I wonder how they do it? Is it just a plug-in meaning that we still have to install Arduino software? Or do they have their own compiler and debugger?

user313: It is almost always the case that a high-level environment like an IDE provides an interface to an existing tool-chain rather than being truly an all-in-one mega-application, which would a maintenance nightmare. Atmel Studio 7 is no exception, and according to Atmel, uses and includes (quite likely by downloading it during the install process) the GCC tool-chain.

Why Atmel Studio asked about Arduino IDE path when I try to import Arduino sketch?

Probably for the Arduino libraries, which are contained within the Arduino IDE executable.

16403: <p>Atmel stated in their website:</p>

<blockquote>
  <p>Atmel Studio 7 features seamless one-click import of projects created in the Arduino development environment. Your sketch, including any libraries it references, will be imported into Studio 7 as a C++ project. Once imported, you can leverage the full capabilities of Studio 7 to fine-tune and debug your design. Atmel Studio 7 fully supports the powerful embedded debugger on the Arduino Zero board. For other Arduino boards, shield-adapters that expose debug connectors are available, or switch to one of the many available Xplained-Mini/PRO boards to fully leverage the Atmel HW eco-system. Regardless of what you choose, you will surely make something amazing.</p>
</blockquote>

<p>I wonder how they do it? Is it just a plug-in meaning that we still have to install Arduino software? Or do they have their own compiler and debugger?</p>
 313: <p>It is almost always the case that a high-level environment like an IDE provides an interface to an existing tool-chain rather than being truly an all-in-one mega-application, which would a maintenance nightmare. Atmel Studio 7 is no exception, and <a href="http://www.atmel.com/Microsite/atmel-studio/compiler-editor.aspx" rel="nofollow">according to Atmel</a>, uses and includes (quite likely by downloading it during the install process) the GCC tool-chain.</p>

<blockquote>
  <p>Why Atmel Studio asked about Arduino IDE path when I try to import Arduino sketch?</p>
</blockquote>

<p>Probably for the Arduino libraries, which are contained within the Arduino IDE executable.</p>
