Importing 3D AutoCAD Models

Working with AutoCAD Files

Fixing Problems in CAD Models

 

Autodesk 3ds Max Tutorials > Project Management > Working with AutoCAD Files > 

Using File Link with AutoCAD Drawings

As you experienced in the previous lessons, the Import functionality of 3ds Max allows you to load drawings and models that were created with AutoCAD, AutoCAD Architecture, or AutoCAD Mechanical. A drawing or model is imported and you can begin making alterations using the tools in 3ds Max.

Importing is fine for a drawing or model that is no longer being updated, but what about a drawing that is still being developed? Architectural drawings can change greatly in a matter of hours, so if you're building a 3D model based on an imported drawing that is still in flux, you will find yourself changing and rebuilding many objects before the project is finished. Perhaps, completely starting over if the drawings change a lot.

This is a situation where using the File Link Manager is invaluable. This lesson will show you the advantages of the tool and how it will save modeling time.

Set up the lesson:

1. Start AutoCAD and choose File menu > Open.
2. Browse to the \tutorial\designviz folder and open ww_cad_drawing2Link.dwg.
3. If you see the Proxy Information dialog, it means there are custom objects in the drawing that require special Object Enablers if you plan to edit them. Click OK for now.
4. Choose File menu > Save As and save the drawing as myDrawing2Link.dwg to the \tutorial\designviz folder.

   This is to preserve the original drawing so the tutorial can be easily repeated.

5. Minimize the AutoCAD window.

Make the link:

1. Start 3ds Max or choose File menu > Reset to rest the program.
2. Choose Files menu > File Link Manager.

   The File Link Manager dialog is displayed.

   

   NoteThe File link Manager can also be accessed from the Utilities panel.
3. On the Attach panel, click the File button.
4. From the Open dialog, browse to the \tutorials\designviz folder and choose myDrawing2Link.dwg and click the Open button.

   

   The drawing appears in the file list.

5. Turn on Rescale and make sure the Incoming File Units are set to Inches.

   You want the units to match the default unit size in the AutoCAD drawing.

6. Click Attach This File.

   You'll see the Status Bar is replaced with the Linking AutoCAD Drawing progress bar.

   Larger, more complex drawing files take longer to link.

   

   The drawing is linked to 3ds Max.

7. Click the Files tab on the File Link Manager dialog.

   

   This panel shows you have one drawing file linked to the scene and the status of the linked file. It also gives you the opportunity to reload, detach or bind a linked file. You'll experiment with these options later.

8. Use Pan, Zoom and Arc Rotate to display the apartment you worked on earlier.

   

What you've just done is create an active link from 3ds Max to a drawing file and verified that the file is linked. Next, you'll start building the model and see how changes to the drawing affect the scene.

Start building a model:

Next you'll build walls, add doors, and assign materials to objects you've created. In this section, you'll start modeling by adding a wall.

1. Continue from the previous section.
2. Click the Snaps Toggle button to activate it, then right-click the same button.

   Right-clicking the button opens the Grid And Snap Settings dialog.

3. On the Snaps panel, make sure Endpoint is the only snap setting that is turned on. Close the dialog.

   

4. Open the Customize menu and choose Units Setup.

   The Units Setup dialog is displayed.

5. In the Display Unit Scale group, turn on US Standard, set the units to Feet w/ Fractional Inches, and then click OK.

   

6. On the Create panel, open the geometry list and choose AEC Extended.
7. Click the Wall button.
8. In the Parameters rollout, set the Width to 5”, the Height to 9'0” and the Justification to Right.
9. Build the wall enclosing the kitchen and end where the fireplace wall meets the exterior wall at the right.

   

10. Minimize 3ds Max and restore AutoCAD.

    The drawing, myDrawing2Link.dwg should still be open from earlier when you set up the lesson.

11. Using the Stretch command, make a crossing selection at the end of the wall that separates the kitchen from the living/dining room.
12. Specify a base point and then enter @3',0 for the second point of displacement.

    

    The kitchen wall is extended to facilitate extra cabinet and counter space.

13. Save the drawing and then minimize the AutoCAD window.
14. Restore 3ds Max and notice the entry in the File Link Manager.

    

    The red flag in the document symbol next to the linked file indicates a change has occurred in the master drawing.

15. Turn off Show Reload Options and click the Reload button on the File Link Manager dialog.

    You'll see the Linking AutoCAD Drawing progress bar, again.

    

    The wall in the drawing is extended but the wall you built is not.

This situation is easy to fix by editing the Wall object at a sub-object level and moving the vertex to match the new endpoint. If you want to add a door, its insertion into the wall will be treated just as you learned in the Editing and Creating Objects tutorial .

Next, after resetting the lesson, you'll learn how to manage layers when a drawing is linked.

Reset the lesson:

1. Restore the AutoCAD window and choose File menu > Close.
2. Open ww_cad_drawing2Link.dwg again.
3. Choose File menu > Save As and resave the drawing as myDrawing2Link.dwg again to the \tutorial\designviz folder.
4. Click Yes when asked if you want to save over the existing file.
5. Minimize the AutoCAD window.

Manage layers:

In this section, you'll work on a scene that already has a drawing linked, but you're going to use some of the layer-management features of the File Link Manager.

1. In 3ds Max, choose File menu > Reset.
2. Choose File menu > Open and open the scene named ww_cad_file_link.max from the \tutorials\designviz folder.

   If you see the Units Mismatch dialog, choose to Adopt The File's Unit Scale.

   

   This scene already has a drawing file linked to it, but one of the layers you need was frozen in AutoCAD and by default, frozen layers do not link unless you specify them.

3. Open the Utility panel and click File Link Manager. Click the Files tab if the Files panel is not shown.
   NoteIf you see a question mark (?) displayed next to the linked file's name in the File Link Manager, it means that the linked file is “lost”. In this situation, you should click the file name and then click the folder icon to browse for the “lost” file. This can occur if you changed the drive location where 3ds Max is installed. The sample files assume an installation using default drive paths.
4. Make sure Show Reload Options is active and click the Reload button on the Files panel.

   The File Link Settings dialog appears.

   

5. Click the Advanced tab and then click the Select Layer To Include button.

   This opens the Select Layers dialog.

   

6. Turn on the Select From List option and deselect all the layers that are frozen except for B-Wall.

   The frozen layers show a snowflake symbol in the middle column. A check mark next to a layer means it will be included when you link a DWG file.

   

7. Click OK after you've deselected the frozen layers and then click OK on the File Link Settings dialog.

   The drawing is reloaded and includes the Layer:B-Wall object.

   

8. Open the Layer list on the Layers toolbar and hide the A-Wall layer.

   

Now that the new layer has been included, you'll use some of the linked geometry to build your model.

Model with linked geometry:

1. Continue from the previous section and select the Layer:B-Wall object.

   

2. Open the Modify panel and choose Edit Mesh modifier from the Modifier List.

   Doing this assigns an Edit Mesh modifier to the linked geometry.

3. From the Selection rollout, turn on the Polygon sub-object level.
4. Select all the faces by dragging a window around the entire object.

   Selected faces are displayed in red.

   

5. In the Edit Geometry rollout, turn on Extrude and set the Amount to 9'0”.

   All the walls and the column are extruded.

   

   NoteThe objects on the B-Wall layer are polylines that enclosed each room. If the extrusion were done to the objects on the A-Wall layer, there would have been some flaws in the extrusion due to gaps and incorrectly attached lines in the drawing.
6. Minimize 3ds Max and restore AutoCAD.
7. Open the Layer list and do the following:
   • Freeze the A-Wall layer.
   • Thaw the B-Wall layer and make it the current layer.
8. Use the Stretch command and stretch the end of the kitchen wall 3'0” to the right.
9. Use the Move command and move the column shape 5'1” to the right.

   The kitchen wall is extended and the column is lined up with the bedroom wall.

   

10. Save the drawing, minimize AutoCAD and then restore 3ds Max.
11. On the File Link Manager dialog, turn off Show Reload Options and click the Reload button.

    The drawing changes are reflected in the model.

    

This last set of steps demonstrated how you can use linked geometry as a basis for building a model. Since linked geometry is the basis for this set of walls, they will change as the drawing changes; however, they are only simple extrusions. If, for instance, you wanted to add a door, these walls will not automatically create an opening when the door is placed. You will have to perform a Boolean operation to manually create the opening in the wall where the door is placed.