Adding Animation

Preparing an animated 3D asset for Simulon follows the same steps as a static 3D asset, but includes the additional step of setting up the animation. As before, we will walk through this process.

Animations

A animations are configured using NLA tracks in Blender or added into an exported .glb or .usdz file. Before setting up the animated 3D asset using NLA tracks, several steps must be completed to ensure the animation functions correctly in Simulon. You can determine what animations will be picked up in the Simulon mobile app by looking at the Simulon Animation panel. This will help you to see whether your animations have been setup correctly.

Ground Contact

Ensure your asset correctly touches the ground, as this determines its spawn position in Simulon relative to the real-world surface.

If you are in Blender, use the X-axis line as your ground/surface reference. In orthographic view, position the base of your mesh directly over the X-axis line.

3D asset incorrect positioning by intersecting below the x-axis line vs correct positioning above the x-axis line.

Origin

Like static 3D assets, it is essential to place the animated 3D asset at the origin, particularly for multiple animations, to ensure consistent positioning at the start of all animations.

In addition to positioning the animated 3D asset at the origin, it is recommended to have it front-facing to ensure that the animation occurs towards the camera.

A sequence of three different animations initiated consistently at the origin.

NLA Setup

Animations in Blender are created from actions and NLA tracks. While Simulon can read animations saved as actions, using NLA tracks is the recommended approach. Before employing the NLA Editor to create NLA tracks, you must first create actions from your animations.

Creating an action involves animating an object or armature by setting keyframes that define its movement, rotation, and scale over time. These keyframes are recorded in the Action Editor as a sequence of poses, forming an action.

Idle action selected in Action Editor.

To convert an action into an NLA track, add the action as a strip by stashing or pushing down the action into the NLA track. Name the NLA track appropriately to reflect the animation. Once uploaded to Simulon, the animation will appear under the name given to the NLA tracks.

Push Down Action button in the NLA Editor.

Tip

NLA tracks are read in the reverse order. Therefore, to set the order of animations for Simulon, arrange the NLA tracks from bottom to top.

It is recommended to set the animated 3D asset’s first animation as an idle or static animation. This is to ensure that the animated 3D asset stays in screens space once instantiated.

The Simulon Asset Preparation plugin gives the ability to also push down all root animations with a specified name. When root animations are detected, a warning will appear with a text box and button called "Create Animation from Root Actions". This allows you to easily create new animations for multiple objects and load them into an NLA Track with a specified name.

Alembic

Simulon has support for Alembic geometry caches. Currently this only works for fixed geometry caches but not alembic emitters.

In Blender you can import you .abc file. Here it will setup a MeshCacheSequence modifier or a TransformCache modifier. If you simply upload this .blend a default animation will be created for the alembic file. But if you'd like to bind the alembic to a specific animation you can use the "Bind Alembic" tab. When you select an object with alembic attached this tab will appear. You can then select the animation you wish to bind it to and click "Bind Alembic to Selected Animation". You can also select multiple alembic objects and use "Bind Multiple Alembic to Selected Animation".