Create and modify 3D models > Modify 3D geometry > Modify 3D geometry overview
  
Modify 3D geometry overview
The commands in the Modify 3D group change existing 3D solids by adding blends, moving faces, and so on. Whenever possible, you should start with a simple shape then use the commands in the Modify 3D group to add details. Blends, chamfers, and tapers are adjustable, so you should use these commands whenever possible. You can use the commands in the Modify 3D group on multiple parts. For example, you can use the Move 3D command on multiple parts by drawing a box around the parts in the viewport or selecting faces from different parts directly. You can use Move 3D and Stretch 3D command with Transform Objects option to select whole parts and assemblies and reposition them.
For example, these two parts look like they have the same geometry:
However, the profiles we extruded looked like this:
We added a blend to the top right corner of the blue part. Now we can easily change its radius. We cannot change the radius on the red part with Modify Blend command.
Modify 3D tips
You don't need a workplane or profile. Modify 3D commands work directly on the 3D object.
Leave the Chk & Fix option active. This option checks for self-intersections, knife edges, and void shells in a part and attempts to fix them. If a part fails the analysis, the command will not complete. If you decide to switch off the Chk & Fix option, make sure that you perform a part check later to verify the integrity of the part.
Modify 3D Partial Result and Error Feedback
When you use commands in the Modify 3D or Engineering group on multiple parts, the operation can succeed or fail on each part individually. Successful operations are displayed as partial result and the failures are displayed as labels (error feedback) on the relevant parts or faces. To disable error feedback, see Skip and Mark. Partial results are not displayed for the Cut, Paste, or Pull (Modify 3D) commands.
When a partial result is available (successful operations and failures appear), a message window is displayed. You can click:
Continue: The partial result is treated as a successful operation and the failures are ignored.
Cancel: The partial result is treated as an error and the operation is canceled in the viewport, but the relevant dialog box remains open.