In most cases, when using the same data with two or more different Autodesk products, it's preferable to use the to connect to drawing files; this lets you maintain a “live” link between the applications. However, if you prefer you can also use the Import command to bind to the drawing file immediately.
The Geometry panel of the Import Options dialog controls how 3ds Max derives AutoCAD primitives and whether 3ds Max uses the scene material definitions when linking to or reloading the AutoCAD drawing. It also presents options for geometry translation and for toggling inclusion of certain elements in the DWG or DXF file.
The Spline Rendering panel of the Import Options dialog lets you determine how spline objects imported from DWG and DXF files are displayed in the viewports and how they're treated by the 3ds Max renderer.
The new contains many improvements, including enhanced DWG compatibility and greater user control and customizability; however, some things were also lost from the DWG Import found in previous versions of 3ds Max. For this reason, 3ds Max retains the legacy DWG Import functionality.
When you export an AutoCAD drawing file, you convert your 3ds Max objects into AutoCAD objects. Because AutoCAD doesn't support animation, the exporter produces objects in a static state defined by the current frame set by the time slider.