When ball is out of bounds
Your ball at rest is out of bounds only when all of it is outside the boundary edge of the course.
图示18.2a：球出界的条件
image
只有当球整体位于球场界线之外时，该球即出界。该图示举例说明球何时位于界内，何时位于界外。
Related Rule - 18.2a(2)