Hi Mike, so yes Orient and CPlane are related because they both use the "orientation picker" as part of their operation.

CPlane uses the orientation picker to specify an x/y/z axis orientation for the drawing plane, and the Orient command uses it twice - once to set up a base frame and a second time to set up a target frame which then will do a combination move and rotation of objects to do a transform from the base to target frames.

The "Orient line to line" and "orient view to view" commands are not quite so strongly related to cplane - but all 3 orient commands are basically tools that combine movement and rotation in a kind of convenient way. You could get the same result just by using the Move and Rotate 3D command on your objects but it could take a lot more work for the cases where the orient tools are optimized to handle.

The most simple one of the orient tools is orient view to view - all it does it rotate objects from one view to align them to a different view. Say for example you open up an AI file and it is currently sitting in your Top view. But instead of it being in your top view you actually wanted it to be flat to the Right-side view. Orient view to view is optimized for dealing with that exact situation - select the objects you want to transform, run orient view to view and then click once in the Top view and a Second time in the Front view and your objects will be rotated in such a way that they now look the same in the Front view as they did in the original Top view. You can do the same thing with manual rotations, this is just a convenience for doing a quick type of rotation to align between different views where you get to just click in the specific views to do it.

Orient line to line is another mostly convenience type thing - for that you pick 2 base points and 2 target points, and the resulting transform will be the same as a move from the start point of the base line to the start point of the target line, combined with a rotation by the angles between the lines. Again it's just a combination of movement plus rotation it can just be less picks and therefore more convenient with some kinds of positioning tasks.

The Orient (just plain "orient", not the "line to line" or "view to view" variety) is somewhat more involved - it also just does what amounts to a move plus a rotation but it is focused on aligning things to surface normals or curve tangents.

See here for some other explanations of orient and see if those help any:
http://moi3d.com/forum/index.php?webtag=MOI&msg=3424.13
http://moi3d.com/forum/index.php?webtag=MOI&msg=3424.14
http://moi3d.com/forum/index.php?webtag=MOI&msg=4228.9
http://moi3d.com/forum/index.php?webtag=MOI&msg=3660.5


> This file is a part of a model that is part of a larger model, so the need to cut
> a circular array of the "scoop" object not aligned to x,y or z would be nice.

So you can see there in Burr's video how the cplane tool can help do exactly that!


> I think I have the hang of it, except for what happens when you start moving
> the white ball around and you change the Z orientation.

Basically you're over complicating it! :) - the orientation picker will align its z axis to be perpendicular to the surface when you first place it so for your case there it's in the orientation you want right when you first place it. So when it's in the orientation you want right from the start, don't mess with dragging any of the pieces of it around, just right click to accept the current position and you've got it.

You only need to mess with more manipulation of those axis lines if you need to do something more custom than that like point a particular axis towards one specific point. If you just want to get something with the z axis aligned to either the surface normal where you placed the base point or a curve tangent on a curve, your first pick already does that (unless you have turned off "align to objects").

See a couple of the above links for some demos that show how you might want to adjust the axis for some particular situations like when you're trying to place some kind of asymmetrical part and you want to align a pointy feature on it towards a specific point on the target face.

Let me know if you are still stuck after seeing the explanation above and on those other links. If you are stuck on something new (like some example with orient or whatever) it helps to post an example file so that it can be used to directly show you the answer. Let me know if Burr's example video and the above explanation still does not answer your question about how to get the result you want with your first example file - the steps there are just to use View > CPlane - place the origin point for the cplane where you see Burr do it, and then the next stage is that you just right-click to accept the position that it is in and then your cplane is set as you need it right after that. With the cplane set the circular array will go in the direction you wanted and then right-click on View > CPlane after you're done to reset it.

- Michael