Creating sections in Autocad 3d is a useful feature when working with product design or building mechanical components. We explore this function in our Autocad 3d courses. 
One method for creating sections is to utilize the Shell and Slice commands. For the valve housing pictured here we would first create a series of cylinders, eg. radius 100mm and height 200mm for the bottom one. Then create a further two cylinders on top.
Go now to the Home tab > and choose the Union function. Draw a Line underneath – this will be our guide line for the slice. Click on the mid-point of the bottom cylinder first, then to the side with F8 (Ortho) on. Then extend the line outwards so that it dissects the cylinder (as above). On the Home tab go to the Solid Editing panel > click on the drop-down menu under Separate > and choose Shell (or in the pre-2009 interface: Modify > Solid Editing > Shell). Click on the object > and hit Enter. then type in the Shell offset: eg. 5mm. Hit Enter twice to exit, then click on the object to see the 5mm offset, and hit Escape. Then subtract the inner shape using Home tab > Subtract.
To achieve a section we will use the Slice command. From the Home tab go to the Solid Editing panel > Slice (pre-2009: Modify > 3D Operations > Slice). Then select the solid. Next select one endpoint of the line created earlier; then the other endpoint. Click above the solid – it should now slice in two pieces. You can further subtract shapes from this object – create a new cylinder in the middle. R20 and go the the Home tab > Subtract.
The 3d interface in Autocad is user-friendly and easy to learn, and we take time to teach a broad range of applications in our classes including modeling, materials, lighting and animation. See many examples of our clients’ work on our Facebook page. For more information there are lots of resources on the web, but try the Autodesk site to begin with: www.autodesk.com. Support options and user forums are also available from the home page.
Other related Autocad 3d Blog Posts:

• Autocad 3d introduction
• Autocad 3d modeling
• Autocad 3d blocks
• Autocad 3d commands
• Autocad 3d basics