ANR Tools

ANR STMap Tracker

Turns an ST map into tracked points and an ordinary Tracker, and turns a Tracker's points into an ST map that bends with the surface.

  • Trackers
  • Trackers pack
  • 3 inputs
  • 26 controls
In Nuke: NodesANRTrackersANR STMap Tracker

Overview

The STMap Tracker works between ST maps and Trackers, in either direction, set by Mode.

ST Map to Tracker: place points in the viewer on the Reference Frame. On every other frame each point sits wherever the map shows the same spot of the surface, so the points follow the surface as you scrub. Create Tracker walks the range and leaves an ordinary Tracker in the script, keyed on every frame and switched off on frames where a point was not visible. The Tracker stands on its own; this node does not have to stay.

Tracker to ST Map: connect a Tracker and the node outputs the deformation its points describe as an ST map, ready for ANR STMap or Nuke's own STMap. Warp Model: Thin Plate Spline pins the surface to every point so a bending surface bends; Perspective fits one plane through all of them and rejects outliers. A map turned into a Tracker and back gives the same map.

Inputs

SourceSTMapTrackerSTMap TrackerOutput
  1. Sourceoptional

    The plate. In ST Map to Tracker it is there to look at while you place points; in Tracker to ST Map, Output: Warped Source warps it as a check.

  2. STMapoptional

    The ST map to turn into tracks (ST Map to Tracker), for example a UV pass or a baked tracker map. U Channel and V Channel say where its coordinates are.

  3. Trackeroptional

    The Tracker whose points become an ST map (Tracker to ST Map). It is read as soon as it is connected; press Reload Tracks after you track or edit it.

Output. In ST Map to Tracker, the input chosen in View (Source or ST Map), with the points and their paths drawn in the viewer. In Tracker to ST Map, the ST map, or the Source warped by it with Output: Warped Source.

Quick start

  1. For tracks from a map: connect the ST map to STMap and the plate to Source, leave Mode on ST Map to Tracker.
  2. Go to the frame you want to place points on and click in the viewer. The first point sets the Reference Frame; drag to move a point, Shift-click or Delete to remove one.
  3. Scrub to check the points follow the surface, then set Tracker Uses and, if needed, First Frame and Last Frame.
  4. Press Create Tracker. A new Tracker appears beside the node, keyed and selected.
  5. For a map from tracks: set Mode to Tracker to ST Map, connect your Tracker to Tracker, choose Warp Model and Direction, and feed the output to ANR STMap or STMap with the plate.

The panel

The node's panel as Nuke shows it, with the values of a new node. Click any control to see what it does; tabs and sections work as in Nuke.

ANR_STMap_Tracker1
ModeST Map to Tracker
Reference Frame1
Set To Current Frame
First Frame0
Last Frame0
U ChannelRed
V ChannelGreen
Use ST Map Alpha
Tear Threshold64
Points
Lock Points
Clear Points
Tracker UsesTranslate, Rotate, Scale
Create Tracker
Live Preview
Show Paths
ViewSource
Warp ModelThin Plate Spline
DirectionMatch Move
Smoothing0
AccuracyNormal (4 px)
OutputST Map
FilterCubic
Reload Tracks
Show Grid
Status

All controls

ANR STMap Tracker26 controls
ModeMenumode

Which way round to work.

ST Map to Tracker: Place points in the viewer; they follow the map, and Create Tracker leaves a Tracker4 behind.
Tracker to ST Map: Read a connected Tracker and output the deformation its points describe as an ST map.

Default: ST Map to TrackerOptions: ST Map to Tracker Tracker to ST Map

Reference FrameSliderreferenceFrame

The frame the points are placed on, and the frame the ST map treats as the rest pose. The first point you place sets it.

Default: 1

Set To Current FrameButtonsetReferenceToCurrent

Sets Reference Frame to the frame you are on.

First FrameSliderfirstFrame

Range Create Tracker walks. Leave both at 0 for the ST map's own range.

Default: 0

Last FrameSliderlastFrame

Last frame Create Tracker walks, with First Frame. Leave both at 0 to use the ST map's own range.

Default: 0

U ChannelMenuuChannel

The ST map channel holding the horizontal coordinate.

Default: RedOptions: Red Green Blue Alpha

V ChannelMenuvChannel

The ST map channel holding the vertical coordinate.

Default: GreenOptions: Red Green Blue Alpha

Use ST Map AlphaCheckboxuseStmapAlpha

Treat map pixels with zero alpha as empty, so a point there reads as not visible rather than reading a coordinate that is not on the surface.

Default: off

Tear ThresholdSlidertearThreshold

Neighbouring map pixels further apart than this, in source pixels, are an edge between surfaces rather than one surface stretching, and a point is not followed across it. 0 follows everything.

Default: 64

PointsTextpoints

One "x y" per line, in pixels, as placed on the reference frame. Click in the viewer to add, drag to move, shift-click or Delete to remove.

Default: empty

Lock PointsCheckboxlockPoints

Stop the viewer adding or moving points, so a stray click cannot disturb a layout you are happy with.

Default: off

Clear PointsButtonclearPoints

Removes every point placed in the viewer, so you can start the layout again.

Tracker UsesMenutrackerUses

Which of the Tracker's transform boxes the new tracks are ticked for.

Default: Translate, Rotate, ScaleOptions: Translate Translate, Rotate Translate, Rotate, Scale

Create TrackerButtoncreateTracker

Follow every point across the range and leave an ordinary Tracker4 in the script, keyed on each frame and switched off where a point was not visible. The Tracker stands on its own: this node does not have to stay.

Live PreviewCheckboxlivePreview

Follow the points as you scrub. Turn it off if the ST map is expensive to compute; Create Tracker still works.

Default: on

Show PathsCheckboxshowPaths

Draw the path of each point through the frames looked at so far.

Default: on

ViewMenuview

Which input the node passes through while you work.

Default: SourceOptions: Source ST Map

Warp ModelMenuSome modeswarpModel

What the points are allowed to describe.

Thin Plate Spline: Every point is a pin; the surface bends between them.
Perspective: One plane through every point, outliers rejected.

Default: Thin Plate SplineOptions: Thin Plate Spline Perspective

DirectionMenuSome modesdirection

Match Move: the map carries the reference frame's picture onto this frame. Stabilise: the other way round.

Default: Match MoveOptions: Match Move Stabilise

SmoothingSliderSome modessmoothing

0 passes the surface exactly through every point. Raise it to let noisy or contradictory tracks average out instead of tearing the surface to reach each one.

Default: 0

AccuracyMenuSome modesaccuracy

The spline is evaluated on a lattice and interpolated between vertices. Normal is 4 pixels apart, which is under a hundredth of a pixel of error on an ordinary move; Exact evaluates it per pixel and costs a great deal more with many points.

Default: Normal (4 px)Options: Draft (16 px) Normal (4 px) Exact (per pixel)

OutputMenuSome modesoutput

The ST map itself, or the Source warped by it as a check.

Default: ST MapOptions: ST Map Warped Source

FilterMenuSome modesfilter

Used only by Warped Source.

Impulse: No filtering: the nearest source pixel.
Bilinear: Linear interpolation between the four nearest pixels.
Cubic: Smooth cubic, no sharpening (B=0, C=0).
Keys: Catmull-Rom: moderate sharpening (B=0, C=0.5).
Simon: Sharper cubic (B=0, C=0.75).
Rifman: Sharpest cubic, may ring (B=0, C=1).
Mitchell: Mitchell-Netravali (B=1/3, C=1/3): a balance of blur and ringing.
Parzen: Cubic B-spline (B=1, C=0): softest, never rings.
Notch: Flat-topped cubic (B=1.5, C=-0.25): suppresses the finest detail.
Lanczos4: Lanczos, 2 lobes.
Lanczos6: Lanczos, 3 lobes.
Sinc4: Windowed sinc, 4 lobes: sharpest, most ringing.

Default: CubicOptions: Impulse Bilinear Cubic Keys Simon Rifman Mitchell Parzen Notch Lanczos4 Lanczos6 Sinc4

Reload TracksButtonSome modesreloadTracks

Read the connected Tracker again. Connecting one reads it by itself; this is for after you have tracked or edited it.

Show GridCheckboxSome modesshowGrid

Draw where a regular grid of the reference frame has moved to.

Default: off

StatusStatusstatus

What the last action did. Refreshes when a control changes.

Tips

  • Turn on Lock Points once the layout is right, so a stray click cannot move a point.
  • Show Paths draws where each point has been on the frames you have looked at; Show Grid (Tracker to ST Map) shows how a regular grid of the Reference Frame deforms.
  • If the ST map is slow to compute, turn off Live Preview; Create Tracker still works.
  • Raise Smoothing when noisy or contradictory tracks tear the surface; 0 passes it exactly through every point.
  • Use Output: Warped Source to judge a Tracker-to-map result directly, then switch back to ST Map for the comp.

Good to know

  • Points are placed and edited on the Reference Frame only; on other frames they are drawn where the map takes them.
  • Neighbouring map pixels further apart than Tear Threshold count as an edge between surfaces, and a point is not followed across it.
  • The tracks read from a Tracker are kept in the node, so a saved script renders the same map without reading the Tracker again. When you change the Tracker, press Reload Tracks.
  • When a Tracker is connected while the Reference Frame is still at its default, the node takes the Tracker's reference frame.

Something unclear or missing? Write to [email protected].