Skip to content

Latest commit

 

History

History
121 lines (87 loc) · 7.02 KB

ShapeAnimations.md

File metadata and controls

121 lines (87 loc) · 7.02 KB
Raw

Shape Animations

Index

Introduction

A common technique for creating face animations is to use Poses or Shapes for the different phonemes that the character should go through when talking.

In this tutorial, we are going to explore how to create a couple of poses and animate them.

Terminology:

  • Shape Keys: a certain pose defined in Blender. This pose can be blended with other poses to different degrees to achieve new poses

Set up

To make this tutorial simple, the Animation is going to be applied only to the default cube.

To see a better representation of face animations, take a look at this example.

Create a new scene in Blender and split it into two, in the second view select Dope Sheet and Shape Key Editor. shape-animations1.png

Select the default cube and go to the Vertex or Data tab. Under Shape Keys press the + button three times to create three Shape Keys. shape-animations2.png

The Basis is the base shape and the other shape keys are going to be the poses that we apply over the base.

Select Key 1 and go into Edit Mode (press tab).

Once you are in Edit Mode press s (scale), 2 and Enter to scale the cube two times.

Then select Key 2 and press again s, write 0.5 and Enter to scale the cube to half size.

Now you have three shapes to animate.

Go into Object Mode by pressing tab and at the bottom you should see that the current frame is 1. shape-animations3.png

Select Key 1 and in value set it all the way to 1.

Hover the mouse over value and press i to insert a keyframe at frame 1.

Then, select Key 2 and leave value as it is, Hover the mouse over value and press i to insert a keyframe at frame 1 for Key 2.

You should see in the Dope Sheet view that now there is a new "Key Action", press F next to it to save the action by associating it with a fake user.

Now, set the current frame to 60 and repeat the above process but setting value to 0 for Key 1 and 1 for Key 2, remember to insert the keyframes (the values should turn yellow).

Set the End frame to 60 and press play to see the cube changing size. Of course, this is a simple animation but with some imagination, something much more complex can be achieved like face animations.

Last but not least for the blender2ogre add-on to properly export the animation it is necessary to turn it into an NLA Track, and select the Push Down button next to the action name. shape-animations1.png

You can now go into the NLA Editor view and change the name of the NLA Track that name is the one that is going to be exported.

Baking complex animations into Shape Animations

How to Bake Modifier Animation in Blender / 1. Wave Modifier Animation to Shape Keys! https://docs.blender.org/manual/en/latest/addons/import_export/shape_mdd.html

Blender can perform some complex vertex animations (Wave Modifier being an example). However, it is not possible to just export these animations into OGRE directly. But there is a trick to baking these animations into Shape Key Animations and then it is possible to export into OGRE. The trick consists of exporting the animation using the NewTek MDD format and then importing it, the resulting mesh will have the vertex animations baked as a Shape Key Animation

NOTE: Care must be taken if the animation has too many frames since there will be one Shape Key for every frame and that makes the exported mesh heavier.

The steps are the following (for example using Wave Modifier):

  1. Add a plane mesh (Shift-A -> Mesh -> Plane), then enter Edit Mode (Tab) and subdivide the mesh (Ctrl-E -> Subdivide) 5 times so the Wave Modifier has some geometry to work with
  2. Set the object shading to smooth (Object -> Shade Smooth)
  3. Add the Wave Modifier to the "Plane" Object and rename the "Plane" to "Wave"
  4. Set the starting and ending frames of the animation (lower right corner)
  5. Enable the NewTek MDD Add-On (go to Edit -> Preferences -> Add-ons -> NewTek MDD and enable the Add-on) 6a) Make sure the Plane/Wave object is selected 6b) Export the animation to an .mdd file: File -> Export -> Lightwave Point Cache (.mdd) and set a proper filename like wave.mdd
  6. Duplicate the Plane object (Shift-D) and set a name like Wave2
  7. On the Duplicate Plane object, remove the Wave modifier 9a) Make sure the duplicate object "Wave2" is selected 9b) Now import the recently exported .mdd file: File -> Import -> Lightwave Point Cache (.mdd) Now the duplicate object "Wave2" has a number of Shape Keys, each for every frame that was exported in step 6b) Besides a new action KeyAction is created, which you can see in the Shape Key Editor of the Dope Sheet (Shift-F12)
  8. Now to get blender2ogre to export the animation we need to create a NLA track, go to the Animation and in the upper left corner change the view to Nonlinear Animation
  9. Perform a push-down of the animation toward an NLA Track
  10. Set the name of the NLA Track, which will be the name of the Shape/Pose Animation in OGRE
  11. Now use blender2ogre to export the animation, make sure the option SHAPE_ANIMATIONS is set to True

Using Shape Animations in Ogre

Create an Entity and attach it to a SceneNode

Ogre::Entity* cube = mSceneMgr->createEntity("Cube", "Cube.mesh");
Ogre::SceneNode* cubeNode = mSceneMgr->getRootSceneNode()->createChildSceneNode("Cube");
cubeNode->attachObject(cube);

Get the AnimationState, enable it and set the starting time position

auto animationState = cube->getAnimationState("KeyAction");
animationState->setEnabled(true);
animationState->setTimePosition(0);

Then you need to addTime() to the AnimationState, we will use a controller for that.

auto& controllerMgr = Ogre::ControllerManager::getSingleton();

// Create a controller to pass the frame time to the Animation State, otherwise the animation won't play
// (this is a better method than using animationState->addTime() in your main loop)
controllerMgr.createFrameTimePassthroughController(Ogre::AnimationStateControllerValue::create(animationState, true));

For more information, please take a look at section Vertex-Animation in the manual.

And also consult the Ogre API manual: