Effectors Cookbook

Effector setups taken from working scenes in the Natsura 101 series and the oak recording. For how effectors work, see Effectors; for what each one does to a tree, see Shaping.

Arcing branches

1. On the branch Grow, under Parameters > Shape > Effectors, click Add Effector and choose Gravity Effector.
2. In the recording, the new row pulled the branches upright. To make them droop instead, flip the effector's direction: on the Gravity Effector, reverse Gravity Direction (for example to 0, 1, 0).
3. The pull is the same everywhere, so map the row's Scale: click its map button and choose Map from attribute…, then u, then Self. The pull now grows from the base of each branch to its tip, and the branches arc.
4. On the map, raise the output maximum for a stronger arc, and set the output minimum negative to lift the branches near the base.

The arc changes up the tree

1. Select the gravity map from the last recipe in the network view. The toolbar now shows the map buttons.
2. Click Map, then Insert (right). A new map is added after the first and takes over as the map the row reads.
3. On the new map, set Blend Mode to add (it starts on replace), and set Read From to Parent, keeping Attribute on u.

The first map shapes each branch along its length; the second changes that with how far up the trunk the branch starts. To see the links between the maps, choose Interface > Graph > Show Dependency Links on the display toolbar.

Leaves towards the sky

1. On an Assembly Decoration, under Transform, click Add Effector and choose Gravity Effector.
2. Set the row's mode to Flatten. The parts turn to lie flat to the sky; Scale above 1 makes it stronger.
3. To flatten only the leafy ends, click the Scale's map button and choose Map from attribute…, then u, then Self, and leave the output at 0 where u is 0.

The base of each part keeps its shape, the ends flatten, and the parts stay instances.

Mixed gravity on larger parts

For large parts, such as branch modules from Rig to Assembly, one gravity row is rarely enough. On the Assembly Decoration, with a Gravity Effector row mapped from the part's u with Self:

1. Change the row's mode and its map so the ends of each part droop, with a little of the opposite near the start to lift the base.
2. From the row's menu, choose Duplicate effector. This adds a new row on the same effector, with default settings and no map. Set it to Level (up) at a high Scale, which makes the way the parts are turned less chaotic.
3. Choose Duplicate effector again and set that row to Flatten.

Mixing the three gives the canopy its shape. A stronger flattening near the base of the tree is a good next step.

Break up regular growth

Add a Noise Effector to a Grow, or to an Assembly Decoration to vary the parts.

To break up the trunk and branches after growth, use the Simulate:

1. Check that Enable Postprocess, under Globals, is on.
2. Under Postprocess (Experimental) > Substeps (Experimental) > Substep Effectors, click Add Substep Effector and choose Noise Effector.
3. If it seems to do nothing, raise Segments under Substeps, and check that the branches aren't too coarse: long steps on the Grow leave few points to move.

Keep the Scale low; it gets aggressive quickly.