Adding IPO curves?

Support Basics & Interface
1

Hi all,

Working through the manual, I’m following the small tutorial on RVK animation at:
manual/user/htmlI/x6463.html

Somewhere in there, it states:
“Select Key1 and add an IPO with your favourite method.”

Unfortunately, I can’t figure out what any method is for adding an IPO curve. This section:
manual/user/htmlI/x6021.html
makes no mention (that I can see) of adding IPO curves.[/i]

2

this is in clear terms how to make an RVK anim:

  1. select mesh and press ‘I’. choose ‘mesh’ and ‘absolute keys’. You may at this point see a speed IPO and a base key for your mesh. If not, go to the menu in the IPO editor that has the various types of IPO curves listed. choose ‘vertex’. this will display your RVKs.
  2. now then,…advance 5 or 10 frames, go into edit mode, adjust your mesh, press ‘I’ to set another key ( which will appear as a blue line just above your base key ) then,…
  3. hit tab again to toggle back into object mode, and back up the 5 or 10 frames back to your base key ( slowly if you want to see the deform as you go ) and you should be able to see the mesh deform back to it’s original position. ( because the base key is on frame 1 )
  4. Now,…you will have to move your first blue key out of the influence of the speed IPO for now, so that you can make another at frame 5 or ten ( or whatever ) so,…
  5. place your mouse cursor in the ipo window, and press ‘A’ to deselect all ( your speed curve i believe is the default thing that is selected at this point, but you want your first key ) then right click on your first key to select it, and press ‘g’ for grab, and move it up and out of the range of the speed ipo. You can activate any of these keys at any time simply by right clicking them.
  6. now go back to the 3D window, and repeat the process by which you made your first key.
  7. once you have made a few, you may want to change them from absolute keys to relative keys, in order to use the RVK sliders. In edit buttons, look for a button that says ‘relative’, and press it. now you will have sliders for each of your keys in the action window, and you can keyframe their influences there.
  8. if you have trouble still, look for a tutorial by Iaminnocent, or LuckyBreak. Both good.
3

A nice tutorial from IanInnocent - thanks.

4

Key thing to think about…

Each one of those little blue-lines represents a target position or shape for the mesh. (For all of the vertices of the mesh, all at once.) The essential purpose of RVKs is to describe morphing from one position, smoothly, to the next.

The closer the curve gets to one line, the stronger the influence of that position becomes, and the weaker the influence of the preceding position (line…) becomes. When the curve intersects the line, the influence of that position becomes 100%; the mesh “strikes the pose.”

Imagine that the various vertices of the mesh are being “pulled,” as if by various sets of electro-magnets, toward each position. There’s a wrestling-match going on between the previous position and the next one. As the IPO-curve moves away from one line, “those magnets are turned down” (becoming less powerful), and the magnets represented by the line-being-approached “are turned up.” The closer the curve gets to a line, the more influence that position has on the final shape of the mesh and vice-versa.

And so, “that is what those silly blue lines are for!” :smiley:

5

The question was DEFINITELY not, “How do you make an RVK?” The question was DEFINITELY, “How do you create an IPO CURVE”.

I see nothing in that answer which describes clearly how to make an IPO curve.

Can anybody explain how to make an IPO curve? Forget the RVK. In fact, forget everything except the original question.

IPO curve. How many ways are there to make them? The manual wobbles about while vaguely hinting that there may be more than one method, but doesn’t actually describe them (the lack of even the most rudimentary search function adds to the difficulty of accessing information, as well).

How many ways are there to make an IPO curve? What are those ways?

6

There’s the standard Ikey to insert keyframe.
Also, Ctrl-Left click in the IPO window adds a control vertex to the current IPO channel (only one).
Copy/Pasting a curve from one channel to another (using the Up and Down arrow icons in the IPO window header).
And finally using the Python API.

Martin

7

To create a RVK IPO curve from scratch – select the key and then ctrl-LMB to add points to shape your curve. You can also copy an existing IPO curve using the copy to and from buffer options. You can also create the IPO curve using the action editor. There are probably other methods as well.

GreyBeard

8

A topic back from the dead I see.

This may be one answer. It turns out that you don’t actually make an IPO curve - they’re added as a result of doing some form of animation/dynamic lighting/texturing etc. whether that animation’s RVK or non-linear animation. In the IPO window you can then do as Theeth suggests.

You’re right though - the manual is confusing when it says “add an IPO curve using your favourite method”. It’s always been at the back of my mind to contribute to the OS manual sometime but, at my present stage of belnder expertise, that would be like the blind leading the blind.