Histogram POP

Summary

The Histogram POP takes an attribute from its input, creates an output with one attribute (Count attribute) and a specified number of points (Number of Bins parameter), and for each input point, adds 1 to one of the bins. This gives a "frequency distribution".

It divides the entire range of values (Input Range parameter) into a series of intervals, and then counts how many values fall into each interval (bin).

Values of the input that are outside the lower and upper range of the bins can be ignored, clamped to the min or max, or added to two extra bins that count values out of range.

It can also output the interval start values into a separate attribute BinValue.

By it nature, it works on a single component of a vector attribute, such as P(1). You may want to first convert a vector to a float using length() in an Math POP.

You can histogram point attributes or primitive attributes.

The result is often viewed with a POP to CHOP, or with the popViewer component which can show an attribute as a graph.

The Histogram POP takes all the values of a single component attribute, for example P(1) and for each input point, adds 1 to a bin of the output. The output has N bins which is actually N points with one attribute Count. The user specifies the value that the first bin represents, and the value that the last bin represents, and using N, the Histogram POP determines the low and high values represented by each bin. Count starts at 0 for all bins, and the appropriate bin gets incremented by 1 for each input points.

See also: Accumulate POP, Analyze POP, ReRange POP

histogramPOP_Class

Parameters - Histogram Page

Attribute Class attrclass - ⊞ - Makes the POP operate on point attributes, vertex attributes or primitive attributes where applicable.

• Point point -

• Vertex vertex -

• Primitive primitive -

Input Attribute Scope inputattrscope - Scalar input attribute or vector attribute component.

Use Input Range useinputrange - Specify teh range of the input attribute values. Default range is 0 to the number of bins.

Input Range inputrange - ⊞ - When used, the input range gets divided in to Number of Bins.

• Input Range inputrange1 -

• Input Range inputrange2 -

• Input Range inputrangemin -

• Input Range inputrangemax -

Output Bin Value outputbinval - Whether to output a separate attribute with the bin values, when using an input range.

Quantize quantize - ⊞ - Convert values into a finite set of discrete levels.

• Floor floor -

• Round round -

• Ceiling ceiling -

Outside Range outsiderange - ⊞ - Determines the behavior outside the input range.

• Clamp clamp -

• Discard discard -

• Extra Out-of-Range Bins extrabins -

Number of Bins numbins - The number of bins to sort the attribute values in.

Count Attribute countattr - Sets the attribute scope when outputting the count attribute

Parameters - Common Page

Bypass bypass - Pass through the first input to the output unchanged.

Free Extra GPU Memory freeextragpumem - Free memory that has accumulated when output memory has grown and shrunk.

Delete Input Attributes delinputattrs - Only output which attributes you specify in this POP - helps isolate attributes into a separate branch.

Operator Inputs

• Input 0: -

Info CHOP Channels

Extra Information for the Histogram POP can be accessed via an Info CHOP.

Common Operator Info Channels

• total_cooks - Number of times the operator has cooked since the process started.

• cook_time - Duration of the last cook in milliseconds.

• cook_frame - Frame number when this operator was last cooked relative to the component timeline.

• cook_abs_frame - Frame number when this operator was last cooked relative to the absolute time.

• cook_start_time - Time in milliseconds at which the operator started cooking in the frame it was cooked.

• cook_end_time - Time in milliseconds at which the operator finished cooking in the frame it was cooked.

• cooked_this_frame - 1 if operator was cooked this frame.

• warnings - Number of warnings in this operator if any.

• errors - Number of errors in this operator if any.

TouchDesigner Build: Latest\nwikieditor2025.30000

POPs (Point Operators) is a new Operator Family of TouchDesigner that runs on the GPU accelerated graphics card or chips, and creates/modifies 3D data which is rendered by the Render TOP or passed to devices like DMX lighting, LED arrays, lasers or other external systems.

Each SOP has a list of Points. Each point has an XYZ 3D position value plus other optional attributes. Each polygon Primitive is defined by a vertex list, which is list of point numbers.

A sequence of vertices form a Polygon in a SOP. Each vertex is an integer index into the Point List, and each Point holds an XYZ position and attributes like Normals and Texture Coordinates.

A surface type in SOPs that includes polygon, curve (NURBS and Bezier), patch (NURBS and Bezier) and other basic shapes like sphere, tube and metaball. Points and Primitives are part of the Geometry Detail, which is a part of a SOP.

A parameter in most CHOPs that restricts which channels of that CHOP will be affected. Normally all channels of a CHOP are affected by the operator. TOPs have Channel Mask, a similar feature.

An operator whose Bypass flag is set does nothing: All data going into its first input appears at its output unaffected.

The Graphics Processing Unit. This is the high-speed, many-core processor of the graphics card/chip that takes geometry, images and data from the CPU and creates images and processed data.

Attributes are data associated with POP geometry. Points, Vertex (Vertices) and Primitives (polygons, lines, etc) can have any number of attributes.

An Operator Family which operate on Channels (a sequence of numbers (Samples)) which are used for animation, audio, mathematics, simulation, logic, UI construction, and data streamed from/to devices and protocols.