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Animate trees and plants in the wind, as UsdSkel or Alembic

Animating a tree in the wind usually takes a rig, capture weights and an animation to redo for every wind strength. Animated, the CGfield application, builds the skeleton from the geometry and delivers looping animation for four wind strengths, from calm to storm.

A skeleton built from the geometry

The skeleton is extracted from the shape of the tree: trunk, branches and leaves each get their joints, with no setup. Its density follows the size of the subject, from a small fern to a tall tree. If the asset has several geometry variants, like the subjects of a Megascans pack, each one gets its own skeleton and animations.

Four wind strengths in a single file

One gust travels through the whole subject, from the base to the tips. The Calm, Breeze, Windy and Storm strengths follow the Beaufort scale, and the animation loops exactly. Each strength you tick becomes a wind variant of the USD component: you change the wind strength in Houdini with one click, without exporting again.

Steps

  1. Install the CGfield launcher with a free account, then Animated.
  2. Drop a tree as USD, or a folder converted by Everything. FBX, OBJ, glTF, Alembic and Blender files are accepted too.
  3. Check the proposed skeleton in the 3D view, choose the wind strengths, then play the animation on the timeline.
  4. Export: by default the output folder goes next to the dropped asset.

What you get

With “USD component” on, Animated writes a Name_skel folder: Name_skel.usd, the component to drop into Solaris, then payload.usdc, skel.usd, one animation layer per variant in anims and one entry per variant in variants. The component references the original asset: geometry, materials and textures stay in the source pack. It works in Solaris and KineFX.

For Maya, Blender and 3ds Max

The Alembic option writes one .abc file per wind strength, with a materials.json file and the textures. For an asset that comes from Everything, Animated can also deliver, without USD, native .hip and .mb scenes for Arnold and V‑Ray, .blend and .max, built by Everything’s scene writers.

Good to know

Animated runs on 64-bit Windows 10 and 11. The best input is the USD component delivered by Everything: it keeps every material, opacity included.

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