How to create a 3D curved circular shape in AutoCAD



A while back a customer asked how to create a certain shape they need to draw up in AutoCAD. In plan it needs to be a circle but in elevation it should have a curved profile. In this blog I’ll show the process of how to create the shape as shown.

1. 3D curved shape - result


The idea is to create a Network surface and then convert the surface to a solid. Then to use the Intersect command with a cylinder to create the resulting circular shape.  Note that in the process below I have not used exact measurements.

Create Network surface

In order to create a Network surface, I’ll draw four pieces of geometry. One for each side of the network. Create a simple arc in plan to start.

2. 3D curved shape - create arc

Now view the arc in 3D by either selecting the edge of the Viewcube or using Shift and RightMouse button together.

3. 3D curved shape - view in 3D

Make sure your visual style is set to anything other than 2D Wireframe. I set it mine to Conceptual.

4. 3D curved shape - set visual style

If your workspace has not been set to 3D you can set it by selecting the Gear icon on the bottom right and select the 3D Modeling Workspace. Your icons will change and look like the ones should below.


5. 3D curved shape - set Workspace

Now select the arc and a 3d Gizmo will appear on the arc. Select its base and move it to the endpoint of the arc.

6. 3D curved shape - set Gizmo position

Right click the Gizmo and set it to Rotate.

7. 3D curved shape - set Gizmo to rotate

Then select the red band and rotate the arc 90 degrees so that it’s upright.

8. 3D curved shape - rotate 90

Now select the blue band and then click on the copy sub command. Rotate and copy it 90 degrees as shown.

9. 3D curved shape - rotate and copy 90

Now copy both of the arc to the other end of the other as shown.

10 3D curved shape - copy arcs

Now select Mirror3D and select two opposite arcs.

11. 3D curved shape - Mirror two arcs

Then select three points on the ends of the arcs and say Yes to delete the original arcs.

12. 3D curved shape - Select three points

The result will be that two of the arcs will be mirrored.

13. 3D curved shape - Mirrored Arcs

Now the geometry is ready for the Network Surface tool. Select the Surface Tab and then the Network tool. Select two opposite arcs and press enter.

14.3D curved shape - Network surface

Then select the other two arcs and press enter.

15.3D curved shape - Network surface2

The surface has been created.

16 .3D curved shape - Network surface3

Convert to Solid

Now select the Solid Tab and the Thicken tool. Then select the surface and give it a thickness. I gave it a thickness of 50.

17. 3D curved shape - Thicken

Use Intersect tool to create resulting object

Now select the Top icon on the Viewcube so you see the model from the top.

18. 3D curved shape - plan view

Select the Cylinder tool and draw a cylinder as shown.

19. 3D curved shape - cylinder

Just make sure the cylinder pass through the curved shape. If not use the presspull tool to extend the bottom downward.

20. 3D curved shape - presspull bottom

Now select the Intersect tool and pick the two shapes. The result is as shown.

21. 3D curved shape - intersect

You can delete the initial arcs and split the screen into two Viewports.

22. 3D curved shape - two viewports

In the second Viewport set the view to Top.

23. 3D curved shape - result


Using a couple of tools in AutoCAD 3D environment you can create fairly complex solid shapes.