Complex Modeling
Learning Objectives
After completing this tutorial, you will be able to:
• Use the new 3D modeling
tools in AutoCAD 2007 for complex
sculpting.
Required Competencies
Before starting this tutorial, you should have been able to:
• Use AutoCAD at an intermediate
to advanced level
• Manipulate the UCS
• Sweep Surfaces
• Loft Surfaces
• Loft Solids.
The new 3D modeling tools in AutoCAD 2007 allow you to model complex
shapes that previously were not possible
to model in AutoCAD. This tutorial
assumes that the user is
completely familiar with creating precise
2D sketches of arcs, lines,
polylines, and splines in any location
as well as the 3D tools from previous releases.
Toy Car Body
1. Open
the file named Tutorial
6 Car Body.dwg. With all of the construction wires visible it looks like a
very complex file. But we will see that any one sketch is really fairly simple.
Figure 1
2. Turn
off all of the layers except the Clay Block
Sketch and the Solid Model layers.
Make the Solid Model layer the active
layer. The first
sketch is simply
a polyline
rectangle.
Figure 2
3. Set the “delobj”
variable to 0
so
that the sketches will not be consumed. That way if you make a mistake you can go back to the original
geometry. Extrude the rectangle a distance of 80. Turn off the Clay Block Sketch
layer.
Figure 3
4. Make
the Front Profile and Front Guide Wire layers visible. If you examine these sketches one at a time you will find that they are simply arcs of a particular angle and radius.
You might want to dimension them to be sure you fully understand the geometry. See if you can recreate
each sketch in a
new file. The next step
will be to Loft a surface using the green wires as cross‐section profiles
and the cyan wires as guides.
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Figure 4
5. Select the two green wires as cross‐sections then Enter
and click Guides and select the two cyan wires.
Figure 5
6. After
lofting the surface
turn off the visibility of the Front Profile and Front Guide Wire layers. Move you cursor into the area of the Dashboard shown in Figure
6A and a down pointing chevron
will appear. Click
on this to expand the solid modeling tools and select the Slice tool as shown in Figure 6B.
 |
Figure 6A Figure
6B
7. After selecting the Slice tool follow the prompts
in the graphics window. First select the solid. The press Enter and RMB select
Surface from the menu and then select the surface.
If you get a warning about erasing
the solid history
click OK. Finally, select the part of the solid you wish to keep – in this case the solid to the right
of the image in Figure 7.
 |
Figure 7
8. Move
the lofted surface
to the Hidden Surfaces layer (which should be turned off). I prefer to keep all construction geometry
rather than erase it.
Figure 8
9. Turn
on the visibility of the Back Profile and Back Guide Wire layers and repeat the same procedures of creating a lofted
surface and slicing the part, this time
keeping the solid to the left of the lofted surface. When finished turn off the visibility of the sketch layers
and move the surface to the Hidden Surfaces layer.
Figure 9
10. Make the Left Profile
and the Left Sweep Path layers
visible. Select the Sweep tool from the Dashboard. Select
the green profile
as the object
to sweep, Enter and then RMB select Alignment No and select
the cyan arc path.
Figure 10
11. Slice the part as shown. From the Visual Style control panel select
Realistic shading.
Figure 11
12. Make the Right Profile and Right Sweep Path layers visible and sweep a surface and slice the part again. (Tip:
It is critically important that you select the correct geometry as the profiles and sweep paths, otherwise
your fillets are going to fail. This
points out that if something doesn’t
work you should go back and
try alternate methods.)
Figure 12
13. Make the Grill Spline, Front Quarterpanel Spline,
Rear Quarterpanel Spline
and the Tail Spline layers
visible. Loft a surface over these splines
as cross‐sections selecting them in order from left to right.
Figure 13
14. After selecting the four splines
hit Enter for Cross‐sections
Only and accept the default settings as shown. (Tip:
These splines were created across Point entities, be careful to select the splines
and not the points when creating
the surface.)
Figure 14
15. Use this surface
to slice the solid retaining
the lower portion
of the solid.
Figure 15
16. From the Modify
Tool Pallet select the Fillet tool.
Figure 16
17. Fillet the two edges shown with a radius of 80mm.
Figure 17
18. Fillet the back two corners
with a radius of 20mm.
Figure 18
19. Radius 20 Fillet
the Chain edge shown –
be sure to select the short wire at the
back as indicated.
Figure 19
20. Make the Canopy Profile
and the Canopy Path layers visible. Start the Loft command and select the two blue sketches as the cross‐sections, Enter and then RMB
click Path and then select
the cyan path sketch.
Figure 20
21. Double click on the canopy solid just created
and change the color
to blue.
Union the body to the canopy.
Figure 21
22. Add a 2mm fillet between
the body and the blue canopy edge as shown.
Figure 22
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23. Save the file.
Figure 23
24. Make the Wheel Wells layer visible
and Extrude the circles
a distance of 100mm.
Do not Union or Subtract the resulting solids.
Figure 24
25. Holding the Ctrl key click on the circular
end face of the front cylinder.
(The original cylinder becomes difficult to see in this screen capture.)
Then select the grip to make it active
and stretch the face as shown. Enter
a distance of 100mm.
Figure 25
26. Repeat for the back cylinder. The model at this stage will be used in the next
tutorial will be used to create a core/cavity mold. Save the file and then Save As with the file name Toolbody. Then close the new file and reopen the Tutorial 6
Toy Car.dwg file.
Figure 26
27. Turn the part over and Shell to a
thickness of 2mm removing
the bottom face.
Figure 27
28. Subtract the wheel wells cylinders from the body and save the file.
Figure 28
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