Update README.txt

Author: Theverat

README.txt

@@ -3,6 +3,7 @@ Building LuxCoreRender with Visual Studio 2017 (Community)
 This basic procedure to compile LuxCoreRender for Windows 64bit is:
 
 1) Install VS2017 (Community Edition works too, https://www.visualstudio.com/downloads/). If you don't want the full IDE you can also install the "Build Tools for Visual Studio 2017";
+Note that you have to enable the "Visual C++ ATL for x86 and x64" in the installer if you want to compile luxcoreui.
 
 2) Install cmake v3.11.2 or better (https://cmake.org/);