Plane Defined by Two Points and a Principal Axis

This type of plane is defined by two points and the condition that the plane is parallel to one of the principal axes. The figures below show the different resulting planes for all three axes using the same two points.

As for the plane by three points, this function checks for points in the select list.

In certain cases, the function automatically determines which axis to use in the plane definition. This is true if the surface normals at both points have approximately the same direction, that means, the principal axis closest to one of the surface normals is also the one closest to the other normal. Then this principal axis is automatically used in the plane definition. In other cases, you are prompted for an axis. The automatic axis selection feature may be disabled by setting the default parameter NO_AUTO_PLANE_AXIS.

Figure 2:29. Plane Parallel to the X Axis.

Figure 2:30. Plane Parallel to the Y Axis.

Figure 2:31. Plane Parallel to the Z axis.

When modifying an existing plane of this type, the following form is used:

Figure 2:32. Pop-up menu for modification of plane defined by two points and principal axis.

By selecting Modify Point 1 or Modify Point 2 you can modify the corresponding definition point. The button Select Axis lets you select another axis. The Select Type button lets you change the type of the plane to any of the plane types described in this section. Finally, Ok quits the Modify function and recreates the plane.

The calculation of the plane will fail if the line between the two points is parallel to the chosen axis.