28.11.2023 – 3D Tracking
Week 9 – 3D Tracking in Nuke
3D System
There are two types of 3D systems, 3D (beta) and 3D Classic. The 3D system was introduced in Nuke14 and supports USD files. When you create 3D nodes, the old version is green, and the new version is red. Typically, new features can be unstable, so it’s advisable to use the old version of 3D nodes for now.
Press tab after clicking on the viewer to toggle between 2D and 3D viewers. Control on the 3D viewer with middle mouse for panning, Ctrl + left mouse for rotating, and the wheel for zooming in/out.
Edit -> Preference -> Viewer Handles -> 3D Navigation: Adjust settings similar to other programs like Maya or Houdini.
To save nodes as a toolset, select the backdrop with nodes and click the wrench button (ToolSets) -> Create. You can easily import the nodes you’ve set and share them (path: C:\Users\*username*.nuke).
ScanlineRender Node: Renders everything in the 3D area to 2D. Adjust quality with Multisample (similar to Maya sampling).
Camera Node: Allows you to look through the camera in the viewer by changing the default to your camera.
Scene Node: Merges multiple objects, connecting each object input to numbers.
Lens Distortion
All camera footage is shot through a lens, which can introduce distortion. LensDistortion nodes help correct and undistort scenes. The LensDistortion node only in NukeX offers features for detecting and solving distortion issues.
You can utilize it just click Analysis-Detect-Solve for simple scene.
If the scene is challenging to analyze, you can add horizontal/vertical lines to aid the process. After add lines, press ‘Solve’ to apply it.
STMap node applies an X and Y transformation to pixels based on two gradients stored in the red and green channels of the input maps. The LensDistortion node can change the Output Mode to STMap, comprising ‘Forwards’ and ‘Backwards’ channels.
By using these channels, you can apply the STMap to the source. This method is much more efficient than employing LensDistortion to analyze each frame individually. Ironically, you can create this effect in NukeX with the LensDistortion node or utilize expressions for the same outcome.
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