Polygonize POP

Summary

The Polygonize POP takes as input a TOP that is a 3D texture (see Texture 3D TOP), or a POP that is arranged as a 3-dimensoinal grid of points (See Dimension) and creates a 3D polygonal surface that encloses pixels or points exceeding a specified threshold.

When the input is a 3D texture, it uses one of the 3D texture's RGBA channels or a combination of them (the Channel menu) to compare against the Threshold parameter. When the input is a POP, it uses a single value float attribute (or component of a vector attribute) to compare against the Threshold parameter.

It makes a closed polygonal surface that encloses all the points/pixels whose values are above the threshold. i.e. All the pixels/points inside the surface are above the threshold, and all pixels/points whose values are below the threshold are outside the surface. (A polygon passes through each pixel where the value is above the Threshold and a neighbor point's/pixels' value is less than the threshold.)

( An example of an input POP that is arranged as a 3-dimensoinal grid of points is a Grid POP with Slices > 1, passed to a Noise POP that creates a single-float Noise attribute whose vaues are between -1 and 1. The Polygonize POP's Threshold parameter would be around 0. )

The density of points in the output can be redued using the Resolution Multiplier parameter.

The surface at the borders of the volume are controlled with the Extend menu - the boundary can be closed or open.

When using a 3D texture, the pixels are assumed to be cubes and the output P(0) range is -.5 to .5. The output can be re-ranged using ReRange P parameters.

See also Trace POP.

polygonizePOP_Class

Input Attribute Scope inputattrscope - When using a POP with dimension 3 as an input, the attribute scope to sample.

Use Position Attribute posattrib - When using a POP with dimension 3 as an input, whether to use the P attribute to position the surface.

Parameters - Polygonize Page

TOP top - TOP to use as image to polygonize.

Channel channel - ⊞ - When using a TOP input, the color channel to sample.

• Luminance luminance -

• Red red -

• Green green -

• Blue blue -

• Alpha alpha -

• RGB Average rgbaverage -

• RGBA Average average -

• RGB Maximum rgbmax -

• RGBA Maximum max -

Resolution Multiplier resmult - Resolution multiplier to apply to the input.

Inside inside - ⊞ - Whether values above the threshold or below or equal the threshold are considered inside. Determines the winding of triangles and subsequently the orientation of their normals.

• <= (Signed Distance) lteq -

• > (Density) gt -

Threshold threshold - The threshold value is where the surface will be created.

Extend extend - ⊞ - Sets the Extend mode when sampling the TOP.

• Hold hold -

• Zero zero -

• Repeat repeat -

• Mirror mirror -

Unique Points uniquepoints - Whether the points are shared between the triangles or unique to each triangle.

ReRange P rerangep - Whether to re-range P.

Map to Low tolow - ⊞ - The low value of the new range in XYZ.

• Map to Low tolow0 -

• Map to Low tolow1 -

• Map to Low tolow2 -

Map to High tohigh - ⊞ - The high value of the new range in XYZ.

• Map to High tohigh0 -

• Map to High tohigh1 -

• Map to High tohigh2 -

Normals Method nmlmethod - ⊞ - How to compute normals for the triangles.

• No Normal none -

• Field Gradient gradient -

• From Surface surface -

Step Multiplier nmlstepmul - When the method is Field Gradient, a multiplier on the size of the step used to calculate the gradient using neighboring field values.

Texture Coordinates texture - Whether to output a point Texture Coordinates attribute (Tex).

Fraction of Max Allocation allocfract - This POP doesn't know in advance how much GPU memory it will need, but except in rare cases (very high amount of detail, a lot of variation in neighboring voxels in the source) it doesn't need the maximum allocation. This allows to save GPU memory. If points and primitives are missing or the info popup shows the max numbers are reached, it means the fraction is too low.

Copy Topology Info Back to CPU cpureadback - Enable copying the point count and topology information held on the GPU to the CPU.

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.

Info CHOP Channels

Extra Information for the Polygonize 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.

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POPs (Point Operators) is a new Operator Family that works with 3D geometry or any general numeric data, runs on GPU-accelerated graphics cards or chips, is rendered as images or passed to devices like DMX lighting, LED arrays, lasers or other external systems.

An Operator Family that creates, composites and modifies images, and reads/writes images and movies to/from files and the network. TOPs run on the graphics card's GPU.

The width and height of an image in pixels. Most TOPs, like the Movie File In TOP can set the image resolution. See Aspect Ratio for the width/height ratio of an image, taking into account non-square pixels.

Attributes make up the numeric data blocks of POPs. Each POPs has three blocks of data: a Point List which includes the P point Position attribute, a Primitive List and a Vertex List, and each are made of any number of attributes.

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.

A CHOP outputs one or more channels, where a channel is simply a sequence of numbers (Samples), representing motion, audio, etc. Channels are passed between CHOPs in TouchDesigner networks. Channels can be Exported to Parameters.

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.

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

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.