From BlenderWiki

Editing Ipo Keyframes

Here we will talk about keyframes selection and edition.

Selecting

In the Ipo Curve Editor, selection of keys varies heavily, depending on the window mode:

Edit mode

Here you select each keyframe (control point) of each edited visible curve, with the usual RMB (or ⇧ ShiftRMB ) click, either on the central point to select a whole control point, or on one of the end points, to select just a side handle (as with standard Bézier curves in Edit mode!). Note that curves in Constant or Linear interpolation mode have simpler control points, made of only one vertex.

You also have the classic “select all” (A) and “border select” (B) tools, as in the “default” mode.

Note that clicking LMB on the rectangles of the right list in this mode will switch back to the default one…

Keyframe mode

Here you select “global” keyframes, i.e. all control points of all visible curves that have exactly the same time value.

Click RMB (or ⇧ ShiftRMB for multiple (de)selection) on the yellow vertical line representing a keyframe to select it.

Once again, you can use the “select all” (A) and “border select” (B) tools.

Note that:

• In this mode, there is no “selected” curves.
• Clicking LMB on the rectangles of the right list has no effect at all. As soon as an Ipo curve is visible (white name), its keyframes are “merged” with those from the other visible Ipos.

Editing

As said previously, there are many ways to edit Ipo curves, either from their dedicated Ipo Curve Editor window, or from others. Note that we won’t talk here about edition done from action or nla editors – even though they eventually affect Ipo curves one way or the other, they have their own pages!

Note that most options are common to the three “editing” menus (Curve in default mode, Point in edit mode, and Key in keyframe mode) – but they do not always behave the same, nor even work!

Keyframes

Keyframe editing is mostly done in “edit” and/or “keyframe” modes.

Transformations

You can transform the selected control points or keyframes, as in default mode. Note that for Bézier-interpolated curves, in edit mode, you have full handles, and hence can transform whole control points, or just their end points… Also, you can set the “type” of selected handles, as with classic Bézier curves: auto (⇧ ShiftH, remember also the AltH toggle between auto-clamped/unclamped handles, which is a curve-level setting), toggle between free and aligned (H), and vector (V). In keyframe mode, you can only grab and scale selected elements, and only along the horizontal axis (i.e. you can’t edit the keyframes’ values in this mode, only their time-position).

Snapping and Mirroring

You have the same snap options (⇧ ShiftS or Curve/Key » Snap), this time only affecting selected control points or keyframes:

• Horizontal, To Next, To Frame – Same as above.
• To Current Frame – This will move all selected control points or keyframes to the current frame (the green cursor).

You also have the same mirror options (⇧ ShiftM or Curve/keyMirror), behaving the same way, but only affecting selected elements.

Adding keyframes/control points

You have several ways to add keyframes in “direct editing” (i.e. from the Ipo Curve Editor itself):

• You can insert a keyframe on each selected curve, at current frame, and with the current value of the corresponding curve (I or Curve » Insert Keyframe..., Current Frame option).
• In the “keyframe” mode, you can also select the Selected Keys option after having pressed I, to add keys to curves not having one yet at selected keyframes positions.
• Or you can click CtrlLMB in the main area, and a new keyframe will be added to the active curve at the point you clicked (working only in “default” and “edit” modes).

Duplicating keyframes/control points

You can duplicate selected control points (edit mode) or keyframes (key mode) with ⇧ ShiftD (or Point/Key » Duplicate). As usual, once the operation is done, the copies are placed in “grab” mode, so you can move them away from the originals.

Joining keyframes/control points

You can join selected elements using CtrlJ (or Point/Key » Join), using two different methods:

• All Selected will join all selected elements, at there average position. Obviously, when it affects more than one curve (Keyframe mode, or edit mode with several curves selected), you get one merged control point per affected curve…
• Selected Doubles will merge selected elements that are close enough together. There seems to be no “threshold” setting to control how close they must be to merge, though… Again, control points on different curves are never merged!

Note that even this option is present in the Curve menu (“default” mode), it seems to have no effect.

Deleting keyframes/control points

To delete the selected elements, hit X (or use Point/Key » Delete).

Transform Properties panel

In edit mode, this panel also shows/can edit the coordinates of the single selected point, or the average coordinates of several selected elements. The same goes in keyframe mode: if you have only one selected keyframe, concerning only one visible Ipo curve, you can see/edit the coordinates of this point, else you have the average coordinates of all points underlying the selected keyframes… There is also a quite specific, but sometimes useful, feature: the Speed numeric field and its SET button… As you may know (if you’ve not forgotten all your school math), the speed of an object is given by the gradient of its curve in a time/position graph… And this is exactly what are the LocX, LocY and LocZ Ipo curves! So by setting their respective gradients at a given time point (by rotating the handles at this frame), you can control the speed of the object at this time. Well, this is what does this feature. To work, it needs at least three visible curves (not necessarily the location ones…), and one selected control point on each, at exactly the same time (so it’s easiest to use it in “keyframe” mode). Then, you can type in the Speed field a value (in Blender Units per frame), and click on the SET button – if something’s wrong, it will complain with an error message. Else the affected control points will be rotated so that all three taken together give the wanted speed. Once again, even though this tool works with any set of three curves/keyframes, it generally only makes sense with LocX/LocY/LocZ ones!

Recording Mouse Movements

This is a quite specific (and complex to use efficiently) tool to “draw” Ipo curves. It works in all “modes” – always returning to the default one, anyway… The basic idea is to record (at each frame) the position of the mouse pointer, as value (Y axis) for one or two Ipo curves.

When one curve is visible (if it does not exist yet, the tool will create it), it is the Y mouse coordinates that are recorded. When two curves are visible, the top-most in the right list will record the Y coordinates, and the bottom-most, the X coordinates. When less or more curves are visible, the tool will not work.

To start the record tool, hit CtrlR (or Curve/Point/Key » Record Mouse Movement).

The time (X axis) can be controlled in two ways, as asked by the menu that pops-up just after you started the tool:

• Still – The frame is set to the starting one, and you must hit Ctrl to record the current mouse position and go forward a few frames. Not that even if a key is recorded for each frame, its difficult to go forward for less than three frames each time you hit Ctrl, so you don’t have a great time precision… If you maintain pressed Ctrl, the frames scroll quite quickly. When you reach the end frame, it cycles back to the first one (keeping recording).
• Play Animation – The animation is cyclically played in real time, from start to end frame and back to start one… The mouse’s position is recorded each time you press and maintain Ctrl. To help you, one of the 3D views is “captured” by this tool, and reflects in real time the effects of the mouse’s position. Note also that during the recording, the affected Ipos, if already existing, are not taken into account (i.e. not played).

To validate the record, click LMB , or hit Space. Hit Escape to cancel.

The Timeline’s Automation A similar, but much more easy-to-use tool exists when you want to record in real time the transformations of an object: the Timeline window’s automation.

Indirect Editing

Indirect editing regroups all methods that modify the “shape” of the Ipo curves, either by moving control points (keys), or by adding/removing some, from outside the Ipo Curve Editor. We won’t talk here about editing done in the Action Editor and NLA Editor windows – even though they affect their underlying Ipos, they are covered in their own pages later in this chapter.

Inserting/Removing Keys

This is a method you’re most likely to use heavily! It consists in editing the properties you want to animate directly in the most appropriate window (e.g. a 3D view for object’s location/rotation/scale, or the Shading context, Material sub-context of the Buttons window for material properties, etc.), and then press the I key to add keys at the current frame.

When you press the I key, an Insert Key menu pops-up, with different choices depending on the current window and context (see also this page for more details):

• 3D View – Here you can insert keys to Object/Pose (and Shape) Ipo types:
  • Location, rotation and/or scale. You always insert keys for the whole three components (X, Y and Z) curves. I don’t know what are the VisualLoc, VisualRot and VisualLocRot options…
  • The Layer option allows you to animate the layer in which lays your object.
  • The Mesh/Curve/Surface options concern the Shape Ipo types (i.e. shape keys).
• Buttons – Here you can insert keys to various Ipo types, depending on the context:
  • In Object context (F7), you can, depending on the selected object’s type, insert physical-simulation related keys (like force strength, etc.), which are also in the Object Ipo type.
  • In Shading context (F5), you can, depending on the active sub-context and selected object’s type, insert material, texture, lamp or world related keys.
  • In Editing context (F9), you can, if the selected object is a camera, insert Camera Ipo keys.

The reverse operation is also available, through the AltI shortcut: when hit, a Delete Key menu pops-up, with the same options as the insert one. It will delete the keys at the current frame existing in the chosen group of Ipo curves.

The I/AltI shortcuts always affect all selected objects, and not only the active one, as in the Ipo Curve Editor…

All these different Insert Key/Delete Key menus have an additional option, Available, which inserts/deletes one keyframe in all the already-existing curves of the affected Ipo type, without creating any new curve.

Inserting transform properties keys

To insert transform properties keys (for objects or bones), you can also use the “automation” feature of the Timeline window.

Recording IPOs during a Game session

There is also the possibility, for object transform properties, to record them during a Blender Game Engine session. This is especially useful to simulate some rigid physics, using the Bullet engine of the BGE – see this page for details.