Drawing a Tree

This page draws a tree's main branches by hand, passes them through Natsura, and grows, decorates and reshapes the result like any grown tree.

You should have Natsura installed, with SideFX Labs, and have built Your First Tree. Grow Draw covers the Custom Module node.

Draw the branches

1. Place a Skeleton node (Houdini's own) and press Enter in the viewport. Click to draw a joint chain, Shift-click to start a new chain, and press Enter to stop drawing. Each chain becomes a branch.

Recorded in 0.7.2, with the nodes already placed.

2. Wire the Skeleton into Custom Module EXPERIMENTAL, from the toolbar's Advanced menu. The width is read from pscale (Use Existing Width). To set the thickness yourself, turn on Normalize Width: the widths are remapped into Width Min and Width Max.

Recorded in 0.7.2; the settings are the same in 0.7.3.

Grow on the drawing

1. Place a Grow wired into a Simulate. On the Grow, open Advanced, then Experimental, and set skeleton to the Custom Module (the clip under SpeedTree below shows this field). The Grow now carries the drawn branches.
2. Wire a second Grow into the first Grow's first input. It grows side branches from the drawn ones, with the usual growth controls.

Recorded in 0.7.2; the second Grow carries a Deflection Effector.

3. Decorate the Grows as in Your First Tree. Here an Assembly Decoration is picked in the branch Grow's Decorations slot, and the leaves appear on the drawn tree. Decorations covers the options.

Recorded in 0.7.2.

Reshape with Natsura Shape

1. Choose Shape (Experimental) from the toolbar's Advanced menu and wire the Simulate into its first input. Press Add Shape Effector to add an effector, here a Gravity Effector, and set its Scale. Shape deforms the rig and its geometry after the fact, so the branches and leaves bend together without simulating again.

Recorded in 0.7.2; the Shape settings are the same in 0.7.3.

Bring in curves from SpeedTree

Import Speedtree (Experimental), from the toolbar's Import menu, brings in the curves of a SpeedTree tree through Custom Module. Only the curves come in, not the branch geometry.

1. Place Import Speedtree and set USD file to a tree exported from SpeedTree as USD. Convert Units and Fix Orientation are on by default.

Recorded in 0.7.2; the USD file path is masked.

2. Place a Grow wired into a Simulate, and set the Grow's skeleton (under Advanced, Experimental) to the Import Speedtree node. From here it works like a drawn tree: grow, decorate and reshape it.

Recorded in 0.7.2.

Next

• Grow Draw covers Custom Module's settings.
• Shaping covers the other ways to pose a tree.
• Effectors covers what Shape's effectors can do.

Status

Custom Module, Import Speedtree and Natsura Shape are experimental, and their names and settings may change. Custom Module contains a SideFX Labs node, so it needs SideFX Labs installed.