Wind Config

Wind Config splits a rigged tree into wind layers. Each Wind Config takes part of the tree as one layer, with its own stiffness, and Export Unreal Nanite Assembly turns each layer into a simulation group for Unreal's Dynamic Wind. Wind for Unreal covers the whole setup.

Where it goes

Chain Wind Configs after the Simulate, one for each layer, and wire the last one into the export. Run Simplify Tree Rig and Skin first, so the layers are built on the joints that get exported. The tool is on the Natsura toolbar under Rig & Export.

The first Wind Config usually takes the whole tree as the trunk, with Is Anchor on, and each one after it takes part of the tree for itself. Each layer is named after its node, and that is the name the export lists.

Carving a layer

Carve decides which joints a layer takes, with the threshold beside it. A new Wind Config starts at Width with a threshold of 10, so it takes everything thinner than 10: the whole tree.

• Width (the default) takes joints thinner than the threshold.
• Root Distance takes joints at least that far from the root.
• Tip Distance takes joints within that distance of the tips. Parts hanging off a branch don't count as tips.

Base Group limits the layer to a group. Snap moves a cut that lands mid-branch to a fork: Grow to Junction grows the selection to the previous fork, Shrink to Junction shrinks it to the next, and Nearest Junction picks whichever is nearer. None keeps the cut where it lands.

Stiffness

Stiffness sets how rigid the layer is. It starts at 1, where the layer holds still in the preview, so lower it to see the layer move. How much a joint moves in Unreal comes from the stiffness of its layer and the width of its branch, so thin twigs move and thick limbs hold. Set Response to Stiffness Only if you want every joint in a layer to move alike, whatever its width.

Spread stiffness evenly from trunk to tips: 0.75, 0.5 and 0.25 for three layers, or 0.8, 0.6, 0.4 and 0.2 for four.

Is Anchor marks the layer as the trunk, which Unreal treats as the trunk group.

Preview

Display a Wind Config to see its layers coloured on the tree and the tree moving. Show Skeleton shows the joints, which makes it easier to see where a carve falls, and Show Geometry the mesh. The preview follows the Wind Environment, set from the Wind selector on the display toolbar, and Preview Mode set to Static holds the first frame. It is a guide to where the layers fall rather than a match for Unreal.

Status

How the values translate into Dynamic Wind, especially strong wind, is still being tuned, so the defaults may change. If branches curl in strong wind, lower the Wind Environment's Strength. Snap treats parts as forks, so it can stop early near them. Scenes saved in the 0.7.3 previews with Carve set to Width may open on Tip Distance.