This sample contains a simple mesh generator plugin containing two parameters for width and height and creating a plane consisting of a quad. Plane can be created through viewport dragging using MouseCallback class.

Download "Plane" Plugin Sample

You need to make sure that Autodesk.Max.dll assembly is properly referenced for your version of 3dsmax, by default the project references the assembly in "C:\Program Files\Autodesk\3dsmax2010\Autodesk.Max.dll" but you can change this to any path.

After compiling simply copy the generated .dll file into 3dsmax plugins directory.