Nuke’s 3D System 28/11

• Nuke primarily operates as a 2D compositing software, but it does have some 3D capabilities. The 3D system in Nuke allows you to work with three-dimensional elements within a 2D compositing environment.

• Nuke can be customized in many ways through preference, we can change the 3D navigation method to emulate other 3D software navigation methods.
• We can customize the nuke UI and save the changes with a name as a workspace, so when opening the nuke we can use our preferred workspace
• We can also create certain tool sets to save some time.
• All the saved tool sets, workspace and preferences are saved in the parent folder of the Nuke.

Nuke Camera

Nuke supports the use of virtual cameras, allowing you to create a 3D space and move the camera within it. This is useful for matching the movement of live-action footage or creating parallax effects.

• Create a Camera Node:
  • In the Node Graph, press Tab to open the node creation panel.
  • Type “Camera” and select the “Camera” node.
• Import Camera Data:
  • If you have camera tracking data from external software (e.g., PFTrack, SynthEyes), use a ReadGeo node or similar to import the camera data into Nuke.
• Adjust Camera Settings:
  • Open the Camera node properties by double-clicking on it.
  • Set the film back, focal length, and other parameters to match the real camera used during filming.
• Create 3D Objects:Use Card nodes or other geometry nodes to represent objects in the 3D space.
  • Connect them to the ScanlineRender node for rendering.
• Animate the Camera:
  • Keyframe the camera’s translation, rotation, and focal length to match the movement in the live-action footage.
  • You can use keyframes or expressions to link camera properties to tracking data.
• Camera Projection:
  • Use the CameraProject node to project 2D images onto 3D geometry based on the camera’s perspective.

Scanline Render

The ScanlineRender node in Nuke is used for rendering 3D scenes within the compositing environment. It simulates a simplified rendering process, taking into account the lighting, shading, and textures of 3D objects in a scene.

Node Properties:

• Render Settings:
  • In the ScanlineRender node properties, you can find settings for rendering quality, anti-aliasing, and other parameters.
• Shading Model:
  • Choose the shading model (e.g., Lambert, Phong) that best suits your scene and desired look.
• Background:
  • Specify the background color or connect another image node to the “Background” input for a more complex background.
• Outputs:
  • The ScanlineRender node typically has outputs for the rendered image, depth information, and other auxiliary data.

Lens Distortion

Lens distortion refers to the imperfections introduced by camera lenses that can cause straight lines to appear curved or distorted. In visual effects and compositing, correcting lens distortion is crucial for seamlessly integrating elements into live-action footage. Nuke provides tools to analyze and correct lens distortion.

• Understanding Lens Distortion:
  • Radial Distortion: Causes straight lines to curve, more pronounced at the frame edges.
  • Tangential Distortion: Shifts the image along the horizontal and vertical axes.
• LensDistortion Node:
  • Analysis: Use the LensDistortion node to estimate distortion parameters from a grid pattern.
  • Correction: Apply obtained parameters for distortion correction.
• Undistort and Distort Nodes:
  • Undistort: Use the Undistort node to remove lens distortion.
  • Distort: The Distort node reintroduces lens distortion, e.g., for 3D integration.
• LensDistortion Model:
  • Model Options: Choose a lens distortion model (e.g., “Nuke,” “Brown,” “Houdini”).
  • Parameters (K1, K2, P1, P2): Define distortion correction amount and type.
• Fine-Tuning:
  • Grid Warp: Manually adjust correction with a grid warp in the LensDistortion node.
  • LensDistortionCorrect Node: Use for advanced correction with extra controls.
• Animation:
  • Keyframe Parameters: Adjust distortion parameters for changing distortion over time.
• Checkerboard Patterns:
  • Calibration Aid: Filming a checkerboard pattern aids in accurate distortion analysis.

STmap

An STmap (Spatial-Temporal Map) in Nuke is a representation of the distortion in an image due to various factors, including lens distortion, and it is used to correct this distortion. The STmap carries spatial and temporal information, making it a powerful tool for addressing complex distortions that may vary across different areas of the image and evolve over time.

• Understanding STmap:
  • Spatial-Temporal Distortion: Spatial distortion is caused by lens imperfections, while temporal distortion evolves over time.
• LensDistortion Node and STmap:
  • LensDistortion Node: In Nuke, the LensDistortion node analyzes footage and generates an STmap representing spatial and temporal distortions.
  • STmap Output: The LensDistortion node produces an STmap encapsulating distortions in the footage.
• Usage of STmap:
  • LensDistortionCorrection: The LensDistortionCorrection node uses the STmap to undistort or redistort images.
• Creation of STmap:
  • Calibration Grid: Use a grid during shooting for generating an STmap, providing reference points for distortion analysis.
  • Analysis: The LensDistortion node analyzes the grid to create the corresponding STmap.
• Application to Animation:
  • Changing Distortion Over Time: For evolving lens distortion, animate distortion parameters or use a sequence of STmaps.
• Manual Adjustments:
  • GridWarp and STmap: The GridWarp node, combined with an STmap, allows manual adjustments, helpful when automatic analysis falls short.