Growing From Scans

This page takes a scanned trunk into Natsura, bakes it onto a lighter mesh, and grows branches from its open end.

You should have Natsura installed and have built Your First Tree. Scan Workflow explains the scan tools. The Simple_Scan_Extension.hip example is the finished setup, built on the Trunk_Poplar scan and colour texture that ship with Natsura.

Import the scan

1. Place Import Highpoly from the toolbar's Scans menu, press Enter in the viewport and click Enter State. Hold Alt to move the camera while the wizard runs. In Import Geometry, pick the scan in Source File; it shows as a point cloud.

Recorded in 0.6, with the scan already loaded; the wizard itself is unchanged in 0.7.3.

2. In Import Textures, set the scan's colour texture under Material (and roughness, normal and height if you have them). The colour shows on the points. Press Enter.

Recorded in 0.6; this step is unchanged in 0.7.3.

3. In Transform, check the scale and rotation and fix them with Scale and Rotate. If the scan is 100 times too big or too small, fix Scale and frame it again. Press Enter and confirm.

Recorded in 0.6; this step is unchanged in 0.7.3.

4. In Trim Geometry, switch to a front orthographic view, box-select the points to keep, and press Enter.

Recorded in 0.6; this step is unchanged in 0.7.3.

5. In Pick Profiles, go back to a perspective view, select the opening to grow from (here the ring at the top), and press Enter to finish.

Recorded in 0.6; this step is unchanged in 0.7.3.

To change a step later, use Back and Continue, click a step in the Phase strip, or set Mode to Advanced and edit the fields by hand.

Create the graft mesh

1. Add Create Graft Mesh and wire Import Highpoly's Proxy output into its first input and Profiles into its second. It remeshes the scan with new UVs, and the grid texture near the opening shows where the tiling bark will blend in. For a mesh that is already clean, set Mode to Use Existing Mesh.

Recorded in 0.6; in 0.7.3 Graft Mode has its own folder and UV Unwrap is a toggle under UVs.

Bake

1. Add a Bake and wire Create Graft Mesh's first two outputs into its first two inputs (Proxy and Bake Target). Display the Bake and press Bake All. It writes colour, height and normal maps to Directory ($HIP/Natsura by default), with the scan's own texture at the base and the tiling texture at the opening.

Recorded in 0.6; the Bake's parameters are laid out a little differently in 0.7.3.

The baked mesh and maps are files on disk, so you can load them into other scenes and extend them there.

Grow from the scan

1. Place a Simulate and wire a Grow into it. Select the Grow, choose Trunk Decoration from the toolbar's Decorate menu, and remove the Grow's Trunk Preview decoration with Remove Decoration.
2. Wire the Bake into the Trunk Decoration's first input (Mesh) and clear its Geometry File, which points at an example trunk and takes priority over the input. The Grow now carries the scan.
3. Wire a second Grow into the first Grow's first input. It grows from the scan's opening, with the usual growth controls.

Recorded in 0.6: the Grow parameters and the way the trunk Grow carries its decoration have changed, but the second Grow is wired the same way.

Match the bark at the join

1. Select the second Grow, choose Surface Decoration from the Decorate menu, and remove its Trunk Preview. Wire a Surface Resource with your tiling bark as its Colour into the Surface Decoration's first input.

Recorded in 0.6, where the decoration was dragged over the Grow's internal decoration; in 0.7.3 you add it from the Decorate menu.

2. On Create Graft Mesh, under Graft Textures, set Texture Mode to Resource and drag the Surface Resource into Surface Resource. Press Bake All on the Bake again: the opening now blends into the bark the branches wear.

Recorded in 0.6; the network and Grows look different in 0.7.3, the Graft Textures settings do not.

3. For a smoother change from scan to bark, raise Graft Blend Region and bake again.

Recorded in 0.6; in 0.7.3 Graft Blend Region is in the Mesh Graft folder.

Optional: a tiling texture from the scan

You can bake the tiling bark from the scan itself, so the join matches more closely. Baking for Scans has the full wiring.

1. Select a section of trunk with Scan to Parts, give it a centreline with Scan Rig, and rebuild it as a tube with Scan to Tube.
2. Wire Scan to Tube into a new Bake's first input and Scan to Parts into its second. Under Bake Processes, turn on Make it Tile, pick a Tiling Mode (Tile V by default) and press Bake All.

Recorded in 0.6; the Tiling settings are the same in 0.7.3, the nodes around the Bake look different.

3. Set the baked colour map as the Surface Resource's Colour, then press Bake All on the scan's Bake so the opening picks it up.

Double-click either Bake to edit its maps in Copernicus before they are written.

Next

• Trunk Extension covers the Create Graft Mesh settings.
• Baking covers resolution and the bake settings.
• Extend Scanned Trunks shows the workflow end to end.

Status

The scan tools are experimental and work best on tube-shaped trunks.