Ok, so assuming that you are not trying to affect bones but have created geometry in Modeler with different parts that rotate independently of each other (like a car door for example). The correct way is to ensure that the component (the car door in this example) is aligned with the positive Z.
It's important to remember that LightWave's rotation prioritises the positive Z axis and therefore all global rotation is based on the pitch rotating inline with the positive Z axis.
This is important because when you create any geometry in Modeler that will be rotated in Layout, the pivot point will always have the pitch pointing toward positive z when it initially loads into Layout. All rotations will be calculated in relation to this global rotational value. If you press y after loading the geometry into Layout, and look at the info display in the bottom left, you'll see that the HPB all have a value of zero. This means that the object is set to Layout's default rotation position and the object's pivot point is now aligned in accordance with LightWave's preferred global rotation system.
So knowing this means that when you build your model you have to think very carefully about how any parts that rotate should be built and aligned in the Modeler workspace.
A model's parts that rotate should generally be on a separate layer in Modeler and aligned in the workspace in accordance to how they will rotate. For example a house door will usually rotate on only one rotational axis. That usually being the heading axis. But a car bonnet (hood for our American friends) will generally only rotate on the pitch.
Knowing this means that you would build the car bonnet in line with the z axis, and where you'd want the hinge to be would be in line with the x axis and the edge of the geometry that would have the hinge to be in contact with the origin.
The house door would have the hinge on the left or right edge and would be in line with the y axis and in contact with the origin in modeler, and normally (although it probably wouldn't really matter much in this case) be facing the positive z axis as it runs along the x axis.
When loaded into layout you would then position the objects that rotate where you needed them and they would rotate properly.
That's the correct way.
If, on the other hand, like so many users do, you create your model in modeler with parts that rotate separately cut from the original layer and pasted in place on other layers, then the pivot point moved in position using the Layers>Pivot>Pivot Tool. When you load the model into layout you'll most likely have rotational problems.
So how to fix this?
Well, the answer that I know of is to use nulls.
You create a null and give it a name. Put it in the position of your rotating object's pivot point or close to it. Ensure Parent In Place is activated. Rotate the null to your liking. Select the rotating object and open its motion options. Parent it to the null and rotate the null. The rotating object should now rotate the way you want. If not, repeat unparenting and adjusting the null until it does. The null will be the controller you use for rotating the object.
As a precaution I would then open up the scene editor and lock the rotating object so that you cannot select it by accident, as well as deactivating the null's rotation channels that you will not be using by clicking the H,P or B buttons of the info display in the bottom left of Layout.
This is a method that works well, but not necessarily the preferred LightWave way.
I hope this information helps or that someone finds it useful.
