Use Snap to keypoints to detect only keypoints in your model when entering points. Non-keypoints are ignored. On wireframe items, the cursor snaps to the nearest keypoint.
When this option is selected, the cursor changes to as a reminder that point entry is restricted to keypoints.
To activate Snap to keypoints:
When you model with solids, snapping points are automatically calculated for the following geometric points:
The snapping points become visible when you enter solid creation mode.