In this lesson, you prepare a 2D DWG file as the basis for the 3D house model.
Open the file:
- Start
AutoCAD 2015. - From the
Application menu, choose Open. In the file dialog, browse to the
\3ds max 2016 tutorials\import\AutoCAD_files\
folder. Open
wt_start.dwg.
Note: You can open this DWG file with a version as early as AutoCAD 2007, but be aware that the user interface has changed (in particular, for Layers), and won’t exactly match the steps in this lesson.
The file is the ground plan of a house.
Freeze the layers:
- On the ribbon
Home tab Layers panel, click 
(Layer Properties). AutoCAD opens the Layer Properties Manager dialog.
- On the Layer Properties Manager, click to select the layer 01-Walls.
- On the Layer Properties Manager toolbar, click
(Set Current) to make this layer current. - In the left pane, right-click All Used Layers, then choose Visibility Frozen to freeze all the layers. A dialog appears to inform you that the current layer cannot be frozen. Click Close.
- Click the
icon to unfreeze the 02-Windows layer as well. 
- Click
(New Layer). Name this new layer 3DWalls. Use the square color icon in the Color column to change its color to blue. - Highlight the new layer (3DWalls) and click (Set Current).
- Close the Layer Manager.
The drawing should now show walls, windows, and doors.
This file contains a lot of elements that aren't necessary for the 3D walkthrough. Using the Layer Manager, you can hide all the elements that you will not use. The only layers that are required for this tutorial are 01-Walls and 02-Windows.
Create polylines:
- Make sure Snap is turned off. (Pressing F9 toggles Snap)
- In the viewport, zoom out until you see all the wall lines. This is required for the Bpoly command to work.
- Type bpoly and then press Enter.
AutoCAD opens a Boundary Creation dialog.
- In the Boundary Creation dialog, click
(Pick Points). - Click inside the wall shown in the following illustration, and then press Enter.
AutoCAD creates a polyline.
- Retype bpoly. Click Pick Points once again, then click inside the wall shown in the following illustration. Press Enter.
This time, AutoCAD does not create a polyline. Instead, it dislays an error message:
(If AutoCAD does attempts to create polyline instead of displaying this dialog, press Ctrl+Z.)
The problem is that the wall is not continuous. You must close the gap before you can create a polyline.
- Dismiss the dialog, then press Esc to exit the Bpoly command.
- Zoom in until you get a better view of the gap between the walls, which you can see at the right of this illustration:
- Fix the gap by extending the line on the left to the endpoint of the next wall. Click the line to select it, then drag from its endpoint to the endpoint of the other wall.
Now the wall should be closed.
- Zoom out until you see all the wall lines again, then repeat the Bpoly command.
This time, AutoCAD creates a polyline.
- Use Bpoly to create polylines from all the walls in the drawing file. Don't forget the small dividers between the windows.
If you see a warning that says “Valid Hatch Boundary not found,” zoom out so all the wall lines are visible in the viewport, and then use the Bpoly command again.
- Press Enter to end polyline creation. Note: The new polylines should have the blue color of the 3DWalls layer.
In order to create 3D walls in 3ds Max efficiently, you need to create Polylines using the wall lines and the Bpoly command. This command draws a closed polyline around the boundary of a selected field, leaving the original wall lines untouched. Using polylines instead of lines greatly simplifies the creation of walls later on in 3ds Max.
Save the DWG file:
- Your work in AutoCAD is now done. Save the file as my_wt_2dplan.dwg, and then exit AutoCAD.