Snap Points
Snap points are implied points in the model, for example, the center point of a sphere or end points of a pipe. As well as turning all snap points on and off, it is possible to change the number of pixels used to draw them. See for details on how to do this.
To toggle the rendering of snap points on or off
Go to Viewpoint, Display, Snap Points
or
Click Snap Points
on the Rendering Style
toolbar.