Keep a specified edge stationary, and apply a taper from that edge.
To begin, create a feature with faces or edges to draft.
On the ribbon, click 3D Model tabModify panel Draft.
To specify the draft type, click Fixed Edge.
Define the pull direction. Move the cursor over a face, work plane, edge, or axis, until the direction arrow aligns with the appropriate pull direction. Then click to select.
If necessary, to change the pull direction, click Flip Direction.
Select the faces to draft. As you move the cursor over a face, it highlights in one color, and the fixed edge highlights in a second color. To remove a face or edge from the selection set, press Ctrl + click.
Note: If a face is tangent to other faces, all tangent faces highlight. To select individual faces, disable Automatic Face Chain.
To maintain adjacent blended features, such as fillets, use Automatic Blending. To stop the blended features from participating in the draft, disable Automatic Blending.