1. Select the object to position at the currently focused Viewport's center.
2.
(Option a - recommended). Press Shift-C to open the Commander. Type View Center into the Commander's edit box, followed by the Enter key, in order to execute the command. The following image depicts what should be displayed in the Commander right before you press the Enter key to execute:
or
(Option b - for Cinema 4D beginners). From the Cinema 4D Main Menu, use the Tools -> Axis -> View Center command to perform the desired operation:
The resulting outcome of the above steps is that your object should get repositioned to the currently focused Viewport's center. More precisely, it is the axis of your object that will be used to position it at said center. If your object's axis happens to lie in the middle of the object (i.e., the middle of its points), which is true for many, but not all objects, then your object itself should be positioned at the current viewport's center. If not, you may need to either adjust the object's axis independently of its points or vice versa, which is a separate question/topic (helpful tip: with the object selected in Model mode, use either the Center Axis to or the Center Object to command, respectively. Use the image above to assist you in finding these commands on the menu, if you have trouble locating them). Then reposition the (axis adjusted) object once again at the view center using the aforementioned steps or further manually tweak its position to your heart's content.
Additional note: The View Center command does not change the object's rotation or scale. It is only useful for altering an object's position (assuming that the object is not already at the view center). Primarily, this command is used to bring a "run away object," as is often the case upon initial object creation (but also after pasting from a different scene, as is the case for your particular scenario), to the center of the Viewport, making both it and its axis tool visible. This makes it easier to further refine the object's position within the confines of the vantage point offered by the currently focused Viewport.
I am hopeful that the detailed answer I've provided above is "idiot proof."
Since a good explanation would take some time, let me provide you for the time being, a direct solution to your problem, while also answering some of your questions:
If I understood correctly, you want to take a spline with Type set to "Bezier" and Intermediate Points set to "Uniform" and use those uniform intermediate points to drive the position of an Align To Spline tag (or more specifically get the position values for the intermediate points, as percentages along the interpolated spline).
If this is the desired behavior, you can do the following:
1. Select your original Spline Object, which I will henceforth refer to as the Original Spline.
2. Do a Current State to Object operation on it. This should place a new spline object right below your current one with the same name as the original spline.
3. To avoid confusion going forward, rename this newly created spline to "Interpolated Spline" and I will refer to it as the Interpolated Spline going in the following steps.
4. If you click on the Interpolated Spline to select it, you will see that the Type attribute has been set to "Linear" and that the Intermediate Points attribute has been set to "Adaptive". You can change the Intermediate Points to "None", since for a linear spline, there are no interpolated points.
Now, let me explain what we have done, above. We have created a new spline, that is a copy of the old spline with the following differences:
Original Spline - composed of a mathematical representation describing its curves, combined with an interpolation of that mathematical representation based on your interpolation settings (e.g., "Bezier", "Uniform", and some number of intermediate points you've entered).
Interpolated Spline - composed of straight line segments representing the Line Object that was used to back your Original Spline's mathematical representation
5. Use the Interpolated Spline rather than the Original Spline to drive your Align To Spline tag(s). You can hide the Interpolated Spline object from the Viewport, since the Original Spline is already visible (otherwise you will have one spline on top of another). However, do not disable the Interpolated Spline by clicking on the green checkmark next to it to change it to a red x, or you will not be able to use it as a source for any operation.
6. By attaching your Align to Spline tag to the Interpolated Spline, instead of the Original Spline, you will be able to use the expresso node layout on the previous page to get the positions as percentage locations of all of the points. Likewise, the Align to Spline tag will correctly track your Interpolated Spline, as you see it on the screen (and on the screen when in Modeling Mode it should look identical to the Original Spline), rather than track the mathematical representation of your Original Spline, which you can see by selecting the Original Spline and entering Point Mode.
I hope this is helpful, has resolved your issues, and answered at least some of your questions in the process.
Take-aways:
1. The Align to Spline tag tracks the mathematical representation of the Source Spline object that is specified as the tag's Spline Path. Setting the source original spline's Intermediate Points value to "Uniform" allows for smoother more uniform (i.e., less jumpy) motion between (mathematical) spline points, but does not otherwise change the spline representation that is being tracked by the tag.
Another way to phrase the above is that the Align to Spline tag does not track what you see in the viewport in Modeling Mode. This view is the interpolated representation of your spline. Instead, it tracks the "perfect" mathematical representation of the curvature of your spline, as it would be presented to you by Cinema 4D while in Point Mode (i.e., the viewport representation showing your spline's actual mathematical point positions and any tangent handles associated with them, which are displayed for the points of the spline that are in a selected state).
2. In order to track uniform interpolated points, you need to create a new Spline Object with Type set to "Linear", that represents the Line Object backing the mathematical representation of your "Bezier" (or other type of mathematically based) spline.
3. The aforementioned Line Object based spline can be generated by performing a Current State to Object operation on the original mathematical spline. It's Type will automatically be set to "Linear" and it, rather than the original spline, can be used to drive an Align to Spline tag with the expected behavior of a uniform spline.
Bonus Take-Away:
4. When a Cloner or a Matrix object is set to "Object" Mode and the Distribution is set to "Vertex", it is the vertices of the underlying Line Object that get used and not the vertices of the mathematical Spline Object. In other words, with regard to the points used for placement, these generators do the "opposite" of what the Align to Spline tag does in the context of the above discussion.
