PointsGenerator

Using the PointsGenerator node (NukeX only) you can create a dense point cloud based on the information generated by CameraTracker and use the dense point cloud further to create 3D meshes of your 2D footage. Dense point clouds are a useful starting point for 3D modeling and positioning objects in a scene.

Note: The analysis must be performed in NukeX, but the result can be used in Nuke.

Tip: PointsGenerator's classic 3D system equivalent is the PointCloudGenerator node.

Inputs and Controls

Connection Type	Connection Name	Function
Input	Camera	The camera track of the scene from which you intend to generate the dense point cloud.
	Mask	An optional image to use as a mask. By default, the point cloud is limited to the non-black areas of the mask. At first, the mask input appears as triangle on the right side of the node, but when you drag it, it turns into an arrow labeled mask. If you cannot see the mask input, ensure that the Mask control is disabled or set to None.
	Source	The source footage from which the camera information was obtained.

Control (UI)	Knob (Scripting)	Default Value	Function
PointsGenerator Tab
Path	prim_path	none	The root path of the new object. Path defaults a prim path variable {parent}/{nodename} which is equal to the node name, such as PointsGenerator1 or PointsGenerator5.
Parent Type	parent_prim_type	Xform	Sets the type of prim to create if there are missing ancestors in the path. Note: Setting the Parent Type to None may cause some referenced objects to behave as if they don't exist.
Ignore Mask	ignore	None	Set the mask type to exclude areas of the sequence during generation: • None - none of the footage is ignored. • Source Alpha - use the alpha channel of the source clip to define which areas to ignore. • Source Inverted Alpha - use the inverted alpha channel of the source clip to define which areas to ignore. • Mask Luminance - use the luminance of the Mask input to define which areas to ignore. • Mask Inverted Luminance - use the inverted luminance of the Mask input to define which areas to ignore. • Mask Alpha - use the Mask input alpha channel to define which areas to ignore. • Mask Inverted Alpha - use the inverted Mask input alpha channel to define which areas to ignore.
Set Keyframes
Analyze Sequence	analyzeSequence	N/A	Click to automatically analyze the sequence and set the required keyframes to use when generating the point cloud. Note: Keyframes are selected to provide a large enough camera baseline to triangulate points, but you can add and delete keyframes manually, if necessary.
Keyframes	keyframes	0	Displays the frames used to track points in the input sequence. Both automatic and manual keyframes are shown.
Add	addKeyframe	N/A	Click to set a keyframe at the current frame.
Delete	deleteKeyframe	N/A	Click to delete the keyframe at the current frame.
Frame Spacing	frameSpacing	15	Sets the interval between keyframes when you click Add All. For example, the default value creates a keyframe every 15th frame.
Add All	addAllKeyframes	N/A	Click to set keyframes throughout the sequence at intervals specified by the Frame Spacing control. For example, for a sequence with 30 frames, the default spacing value creates 3 keyframes.
Delete All	deleteKeyframes	N/A	Click to delete all keyframes in the sequence.
Calculated Accuracy	accuracy	0	Displays the depth accuracy calculated at the current frame when using the automatic Set Keyframes method. The accuracy rating can help you to select frame ranges when generating a point cloud - higher accuracy frames produce cleaner point clouds.
Dense Tracking
Point Separation	pointSeparation	2	Sets the separation value, in pixels, for points in the dense point cloud. Reduce the separation to create denser point clouds and vice-versa.
Track Threshold	matchThreshold	0.5	Sets the correlation threshold at which point tracks are terminated. Use a higher threshold to increase the accuracy in matching points between keyframes.
Track Points	track	N/A	Click to display a frame range dialog to determine which frames are used to calculate the point cloud. Use the standard Nuke notation, for example, 1-19, 40-60, 65-100. Points can also be added to the point cloud in stages using different frame range selections. Use Calculated Accuracy to determine the most accurate frames for generation.
Clear Points	clearPoints	N/A	Click to clear all tracked points.
Post Filtering
Display rejected points	displayRejectedPoints	enabled	When enabled, points that fall outside the Angle and Density Thresholds are highlighted in the 3D Viewer. When disabled, all rejected points are removed from the Viewer.
Angle Threshold	minTriAngle	1	Sets the threshold for the minimum angle to triangulate 3D points (in degrees). Points with a large triangulation angle are more accurate. Set a threshold of 0 to triangulate all points. Increase the threshold to retain the more accurate points. As a rule of thumb, anything below 5 degrees is likely to be incorrect.
Density Threshold	densityThreshold	0	Sets the threshold for the minimum density for points. Set a threshold of 0 to output all points and increase the threshold to highlight isolated points.
Delete Rejected Points	deleteRejected	N/A	Click to permanently delete points that are rejected by the Angle and DensityThresholds. Tip: To clean up the point cloud, try enabling Output points per frame and Display rejected points. You can then tune the Post Filtering thresholds and delete points at different frames.
Output
Point Size	pointSize	2	Sets the size, in pixels, of points displayed in the 3D Viewer.
Output points per frame	outputPerFrame	off	When enabled, only the points generated at the current frame are displayed in the Viewer. When disabled, points from all tracked frames are displayed.
Groups Tab
Display groups in overlay	displayGroups	on	When enabled, group colors are displayed as an overlay in the 3D Viewer.
Output visible groups only	outputGroups	off	When enabled, only points designated as part of a group on the Groups tab are displayed in the 3D Viewer. You can label the point cloud using Groups to help visualize different parts of the scene.
Create Group	createGroup	N/A	Click to add the current vertex selections to a new group. You can also use the Viewer right-click menu to create, delete, and modify groups.
Delete Selected Group	deleteGroup	N/A	Click to delete all selected groups and deselect the group in the point cloud. To delete points use Vertex selection mode in the 3D Viewer and press the delete key.
Groups	groups	none	Lists all groups in the point cloud and allows you to set the name, color, and visibility of each group. To create groups, enable Vertex selection mode in the 3D Viewer. You can then select points and use the right-click menu to create a new group or add the selected points to an existing group.
Bake Selected Groups	bakeGroups	N/A	Click to bake the selected groups to a separate, baked point cloud.
Bake Selected Groups to Mesh	bakeMesh	N/A	Click to convert the selected groups to a mesh using Poisson Surface Reconstruction. Mesh creation is based on the SGP 2006 paper, Poisson Surface Reconstruction by Michael Kazhdan, Matthew Bolitho, and Hugues Hoppe. The original source code and paper can be found at http://www.cs.jhu.edu/~misha/Code/PoissonRecon/.
Samples	samplesPerNode	1	Specifies the minimum number of sample points used to calculate mesh points, using floating point values. For noise-free point clouds, lower values in the range 1.0 - 5.0 can be used. For more noisy samples, higher values in the range 15.0 - 20.0 may provide a smoother mesh.
Python Tab (These controls are for Python callbacks and can be used to have Python functions automatically called when various events happen in Nuke.)
before render	beforeRender	none	These functions run prior to starting rendering in execute(). If they throw an exception, the render aborts.
before each frame	beforeFrameRender	none	These functions run prior to starting rendering of each individual frame. If they throw an exception, the render aborts.
after each frame	afterFrameRender	none	These functions run after each frame is finished rendering. They are not called if the render aborts. If they throw an exception, the render aborts.
after render	afterRender	none	These functions run after rendering of all frames is finished. If they throw an error, the render aborts.
render progress	renderProgress	none	These functions run during rendering to determine progress or failure.