| Duik Tools: DuDuF IK Tools for After Effects |
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II - Principle of inverse kinematics III - Controllers, names of the layers, preparations... VI - IK
and puppets VII
- Animation tools VIII -
Cameras IX -
Miscellaneous Screenshots are from the French version of Duik, but duik is available in English! I - Install1- Once you have downloaded the Zip-folder, quit After Effects if it is running, open Windows Explorer, go to the folder containing the scripts for After Effects (windows : "c:\Program Files\Adobe\Adobe After Effects\Support Files\Scripts" - mac : "Applications/Adobe After Effects/Scripts/") and paste in the contents of the Zip-folder (while keeping all the subfolders, you must have a file "Duik.jsx" in a "ScriptUI Panels" folder and a folder called "Duik "in the Scripts folder) 2- Duik is now available on the very bottom of the "Window" menu in After Effects CS3 or CS4 or CS5.II - Principle of inverse kinematics Inverse kinematics (aka IK) is a process allowing to specify the positions and rotations of the joints of a model in order to obtain a pose.E.g. with an arm: rather than to animate the rotations of the arm, the forearm, and the hand one after the other, (which is called FK, "Forward Kinematics"), thanks to an IK all you have to do is to animate the position of the hand for the computer to calculate the rotations of the arm and forearm. The
IK means much comfort and many
possibilities for the animation designer: Animating
a walk or a run is thus much
easier. Technically,
the IK requires "parts" in each limb that are related by a parent
relationship from the end to the root. On the arm for example: the hand
is connected to the forearm, which is connected to the arm, which may
be connected to a shoulder (not necessarily, like we will see). The
pivots must be well positioned about the joints. For those who want to know: mathematically (and so regarding computing), there are two ways to calculate the position of a limb for a limb of 2 joints max. (e.g. shoulder and elbow): using trigonometry, which implies that you have to indicate in which direction the limb will bend (or else, for each position of the end, there will be two possible positions for the limb); or using nonlinear programming, which is also the method used for limbs with more joints and which is not possible using expressions in After Effects. Therefore, Duik allows you to create IKs on limbs of one or two joints (e.g. a single shoulder or a shoulder with an elbow). You can
download here an example of an humanoid that can be animated using IKs .
(Project After Effects CS3) Here
is a Video Tutorial by
Famos which shows you how to
create IKs! III - Controllers, names of the layers, preparations... On
After Effects, to animate in a simple way, it is very handy to create
null objects to which you connect the layers that have to move. These
objects are called controllers Be careful, if you want Duik and the IK to work properly, avoid having two layers with identical names in the composition! The
easiest way to prepare an animation is to place all limbs in the right
way, and then their anchor points. Then link the limbs with each other,
and
finally create the controllers at the places you will need them (in
case you are using IK, create them at the roots and at the ends of the
limbs: feet and hips, hands and shoulders, etc.) You can
download here an example of an humanoid that can be animated using IKs .
(Project After Effects CS3) Applying IK with Duik has been greatly simplified with version 8. In order to apply an IK, you have to select the layers, one by one, beginning by the end, finishing by the root, then you have to select the controller, and finally click on the button "Create an IK". Since version 11, creation of IK's works with 3D Layers too (the only condition is that ALL layers, including the controller, are 3D). ___N.B. : When you apply IK on two or three layers, an option is created in the controller's effects, which allows you to choose the direction you want the limb to bend in. You can animate this effect (thus it is possible to bend an arm in both directions during one animation). ___N.B. : To apply IK with 3D Layers, you have to mention if the layers face the "Front" view (default view when there is no camera) or the "Right" view. ___N.B. : An effect on the controller allows you to adjust the direction of the IK on 3D Layers. You can
download here an example of an humanoid that can be animated using IKs .
(Project After Effects CS3) The
IK Goal has to be applied on one layer. This layer will not be
influenced by the rotation of its parent (applied on a hand, whatever
position the arm is in, the hand keeps its original orientation). To delete an IK Goal, you just have to delete the layer created by the script. VI - IK and puppet Once
you are familiar with IK, you
discover very quickly all the possibilities this technique offers. ___N.B.: the point here is not to explain how the puppet tool works; for more information about this tool, please see the Help of After Effects. Duik offers tools which allow to use IK easily on puppets' pins using bones, which you can create using Duik. ___VI / A - Preparing a puppet Before modifying a layer to create a puppet and add IKs, you definitely need to ensure that this layer has not been applied a transformation like position, rotation, orientation or scale. If it has, you only need to precompose it (Ctrl + Shift + C) by selecting the second option "transfer attributes..." before any operation. ___N.B.: if you press the "U" key twice in a row, it opens all the properties of the layer which have been modified, and thus you can know quickly whether you need to precompose the layer or not. Once
the layer is ready, start
with positioning your
pivot at the right place. ___N.B.: Positioning the pins and managing the distortion mesh quite corresponds to skinning in 3D-animation, except that the rigging is done after the skinning in this After Effects method! Duik innovates and offers objects to control the puppets' pins. This way you cannot only link the pins, but you can also apply an IK system on them! These objects that will control the pins are called Bones. To create them, you just need to select every corner of the puppet that you want to animate and then to click on the "Bone" button. A bone is then created just under the pin and carries its name. ___N.B.: To select the pins more rapidly and more easily, do not forget to select the layer and to press "U"! If you had not renamed the pins, at least think of renaming the bones! Very often there are a lot of them and you can easily get lost... You can find here an example for preparing a leg using IK and puppet (After Effects CS3 project). Once the bones are created, the method to follow is similar to the one concerning "classical IK without puppet" described above. Now you need to create controllers (at least one at the end of the limb you want to animate (hand, foot...) and at the root (shoulder, hip...) if necessary. Finally, you need to create the links (hand child of forearm, which itself is child of arm, which itself can be linked to a shoulder controller or to another object, etc.). You only need to create the IKs using the method described above ( here ), by positioning them on the bones and with the controller at the end of the limb... ___N.B.: The rotation of the puppets' pins is not taken into account by After Effects. However, if you want to rotate the foot, since the controller is usually positioned on the ankle, all you have to do is to add a puppet pin and its bone on the toes, and to link this bone to the controller. The controller's rotation will then rotate the foot (only, of course, if it is positioned the right way on the ankle). A coming version of Duik will use this process to have the "IK Goal" option even on the puppet. You can find here an example for preparing a leg using IK and puppet (After Effects CS3 project). Duik now includes a number of tools making the animations designer's work and the creation of expressions that are often used in After Effects easier. Here is a description.
With the wiggle tool, you understand it from its name, you can add a wiggle expression to a layer's properties, may it be a 3D layer or not. ___N.B.: With the wiggle expression (often called "noise" in 3D softwares), you can create a trembling effect, or a flashing effect, or even a floating effect at low frequencies. It is often used to simulate a hand-held camera, but it can also be very useful for a flashing bulb, a shaking fist, a floating ship, etc... You
just need
to select the layer on which you want to apply the
wiggle, to click on "wiggle", and the above window will pop up. Once the wiggle has been created, controllers are created in the layer's effects, which allows you to manage and animate its amplitude and frequency. (same as the effect "Separate X Y Z position" in After Effects) ___N.B.: Ticking "all axes" is NOT the same as ticking the three boxes X, Y, and Z. Actually, "all axes" creates only ONE controller for all axes, whereas ticking all three boxes creates one controller for each axis and thus allows a different wiggle on each axis. == WARNING == on version 3 of Duik, we know about the following bug: the X and Y axes are inverted for the position (only for the position). This bug is not serious and does not occur when using the box "all axes". It has been corrected from version 4 on. To cancel the effect, you only need to delete the expression in the property on which the wiggle has been applied, and to delete the controllers in the layer's effects. The tool "Wheel" has been created to facilitate the animation of wheels... It automates their rotation according to their movement: the animation designer only needs to animate the position of a vehicle, the wheels will automatically rotate. See example project here (After Effects CS3 project). You just have to select the layer of the wheel (after positioning the pivot on the very centre of the wheel) and then to click on the "Wheel" button. The following window is displayed: It
is necessary to know the wheel's radius, in pixels, in order to animate
it the right way. If you do not know the wheel's radius, Duik can
calculate it! You just need to position the pivot of an object (null,
solid, or any other) on the edge of the wheel. Then select the layer
for the wheel, then the layer used for the measurement, and click on
the "measure" button. ___N.B.: The layer can still be animated with a rotation: on top of it, you can animate the automatic rotation, for example to make the wheel spin. ___N.B.: A too big radius will make the wheel rotate too slowly, and a too small radius will make it rotate too fast. ___N.B.: Once you have the measure, the layer you used to calculate it is useless. If you created a null object only for the measurement, it can now be deleted. The radius' value is saved after the first application, and thus you don't have to measure again to apply the effect on other wheels with the same diameter! To cancel the effect, you can delete the expression in the layer's rotation. It can be very complicated to animate some effects in After Effects, like masks, or for example the centre of a radial blur, even more when you have to work with curves to improve the animation. Duik's "Morpher" tool has been created to make these animations easier. If you use "Morpher" on an effect you can add a controller to the layer, which allows you to redo the interpolations very easily between the keyframes of this effect. Each keyframe on the morpher defines the effect's status as it is on the frame which the user specified on the morpher. Thus there are two ways to use the morpher, which are explained below in two examples. ___Example
1: The user created a mask on a layer. He drew three different shapes
of the mask on the first 3 frames of the composition (without minding
the animation). Thus there are 3 keyframes on the effect "mask path" on
the first 3 frames of the composition. ___Example
2: The user created a mask on a layer. Then he creates an animation on
this mask, but he wants to animate the interpolations between the poses
of this mask more easily. He applies the morpher effect. He positions a
keyframe on the morpher for each keyframe of the mask path, which is
the number of the frame on which each keyframe is positioned. Many effects can be used to simulate a "lens flare", but it is much more interesting to create your own lens flare, with your own layers. The "Lens" button allows you to automate the animation of position of several layers, depending on the position of the light, exactly like on all lens flare effects (See the generation effects in After Effects). Duik also adds a control function for the intensity and the size of the lens flare, which enables to replace totally any other equivalent effect and to customize and create from A to Z your own lens flares. To apply the effect, you need to already have layers for the lens flare in the composition. Select the one of the centre, the one which will indicate the position of the origin of the light (it can be a null object...) then all others (it is important to select the centre first). Then click on the "Lens" button and the effect will be applied on the layers. First, the layers will be automatically distributed in a line which goes from the origin of the light to the opposite side. You
can use several controllers
to
customize and animate the lens flare: ___N.B.: This tool was created to generate lens flares. Therefore it is called "Lens", but it is also possible and very convenient to use it to animate a camera's movement in a multiplan set! Distance link is used to link a value (property, transformation, effect) of a layer to its distance from another layer. E.g. you can link the blur amount on a layer to its distance from a camera (thus creating a depth of field) or you can link the rotation of a layer to its distance from an element of the background (thus creating an automated wheels)... To
apply the distance link, you need to select the value to be controlled,
then the layer from which the distance is measured. Then click on the
"distance link" button. To cancel the effect, you just need to delete the expression of the controlled value and the three cursors added on the layer. Spring is used to automate delays and bounces when an animation stops, like a spring does. When the animation - position, rotation, scale, or any effect - comes to a stop, there are automatically oscillations, which attenuate to finally stop.To apply the spring, you need to select the property to animate, then click on the "Spring" button. Two effects are added on the layer : "Elasticity" to control the frequency and amplitude of oscillations - their speed. Higher is the value, quicker will be the oscillations. "Attenuation" how long will the oscillations last. Lower is the value, longer will last the oscillations. If the value is 0, the oscillations won't stop. If it is a negative value, the oscillations will increase in size. To cancel the effect, you have to delete the expression of the controlled property and the two sliders added on the layer.ss There couldn't be a good animation without a good camera! Duik offers tools to animate cameras more easily, for traditional cameras or even for a 3D rendering. The "Control Cam" tool can be used to facilitate the animation of cameras. It creates three controllers; one controls the position of the target, the second one controls the position of the camera and the third one controls both at once. Thus the first two controllers are used to handle the camera as if it was on a stand and would always stare at the target, and the third controller is used to handle the camera as if it was a hand-held camera, regarding the position and the rotation. To create those controllers, you just need to select the camera and to click on the button. To cancel the effect, you just need to delete the expressions in the camera and the 3 null objects used as controllers. The "3D Camera" tool is used to transform a classic camera into a double camera for a 3D rendering, and it adds controllers to animate it easily. That way, if you select one camera and then click on the button, two more cameras (left and right) are created in the composition, with two controllers, "position" et "target". The two new cameras are used for the rendering of the left and right frames (After Effects calculates the rendering of the composition using the camera which is located above in the pile of layers. You only need to render the composition with the left camera, then the right one above.) The original camera shows the "central" frame, which is used as reference. The "position" controller controls the position of the cameras, the "target" controller defines the target point. The left and the right cameras converge toward this point. The distance between the left and the right cameras is set using a slider in the effects of the position controller. This distance is in pixels; a positive number will position the cameras on the right side (right side on the right, left side on the left) and a negative number will invert the cameras. A zero value will put both at the same place. The cameras' convergence can be set by changing the angle effect on the target controller. A negative angle makes the cameras diverge from the target point, a positive angle makes the cameras converge a little more. A zero value will make the cameras converge exactly on the target point. When
you use expressions to link
layers, there is always the same
problem : coordinates of a layer
(position and rotation) change depending on the composition where it is
and his parent too. Links between those properties can become complex. When
using numerous expressions,
IK's, animation tools, and a lot of
layers, it is important that layers have all different names to avoid
bugs and to be more comfortable. But it can be a long process to rename
a lot of layers. "Links" tool shows all links between layers in a composition, as a simple tree view. You can double click to select a layer. |
