Starting with 3ds Max 2017, you can use the popular cross-platform development package Qt to create the user interface for your 3ds Max plug-in. See the maxsdk\include\Qt directory for headers exposing utilities for integrating Qt, as well as some customized Qt widgets used in the 3ds Max UI. Some of the standard plug-ins shipped with 3ds Max use Qt for their UI, and you can look at these in the SDK samples collection. Look at the maxsdk/samples/systems/sunlight project for an example of a plug-in that uses Qt for its UI. There is also a very simple sample located in maxsdk/howto/objects/qtObjectDemo.

3ds Max uses a patched version of Qt 5.6.3 that is binary compatible with the standard GPL distribution of Qt 5.6.3. Before you can create new plug-ins or build existing ones that require Qt, you need to download Qt 5.6.3, and install the Visual Studio 2015 Qt add-on.

1. Download and install Qt 5.6.3 from www.qt.io/download/
   Note: When installing Qt 5.6.3, the only component you need to install is msvc2015_x64, the 64 bit version for the Visual Studio 2015 compiler.
2. You have two choices for configuring the 3ds Max SDK to use the installed version of Qt:
   • By default, the SDK's $(QTDIR) is defined as <maxsdk>\Qt\<QtVersion> (where Qt_Version in this case is 5.6.3). So you can copy the contents of your Qt install Qt\5.6\msvc2015_64\ to this location. Or:
   • Change the definition of $(QTDIR) in <maxsdk>\ProjectSettings\propertySheets\3dsmax.general.project.settings.props to point to the installed version of Qt. You will also need to change the definitions of $(QtInc) and $(QtLib). You do not need to change $(QtMigrate*).
3. In Visual Studio, go to Tools > Extension and Updates ... > Online and search for Qt. Install the Qt Visual Studio Tools (2015) add-on. You will need to re-start Visual Studio.