Experimental:Curve POP

Summary

The Curve POP is used to generate a curve in XY (Z=0) that can be used as a lookup curve for a Lookup Attribute POP or elsewhere. It is a "function" in that the P(0) X-value steps forward uniformly from point to point, while the P(1) Y-value takes on different interpolated shapes. The curve it generates is also in an attribute Curve, which you can use instead of P(1) for clarity.

Like the S Curve CHOP, it defaults to an ease-in ease-out curve, but the Curve POP lets you add multiple segments (sequential blocks) that enable a greater range of curves. The curve can be made of several segments defined by Sequential Blocks of parameters, each with its own start and end values and Curve Type.

The Curve Type includes Constant, Linear, the Eases and Bezier.

The Alpha and Beta values affect the curve, where Alpha makes it more- or less-sloped, and Beta makes it more biased to the start or end of the segment. When Bezier is selected, Slope In and Slope Out affect the slopes at the end-points of the segment.

More generally, we treat the 2 axes as U and V. The curves can output as points-only, a linestrip, or as an RGBA color curves.

Because the U values can start and end at any value, you can normalize the curve so the U values (P(0)) are between 0 and 1.

The curve can be extended to double length and made symmetric using the Symmetric toggle.

The Lookup page lets you apply the curve as a lookup without first converting anything to points. This preerves maximum accuracy, and avoinds interpolation problems when a lookup curve sharply steps from one value to another as may occur between two segments. IN this case you attach an input POP where you want to modify one or more attributes with the curve. In this mode it behaves similar to the Lookup Attribute POP.

Tip: If you want specific points to exactly hit your U keyframe values, make sure your (Number of Points - 1) is divisible evenly by your U values.

See also S Curve CHOP, Line POP, Lookup Attribute POP, Pattern POP

curvePOP_Class

Parameters - Curve Page

Total Length totallength -

Output Curve outputcurve - ⊞ -

• Points points -

• Line Strips linestrip -

• Color Strip colorstrip -

Normalize U normalizeu -

Symmetric symmetric -

Parameter Size parsize - ⊞ -

• 1 1 -

• 2 2 -

• 3 3 -

• 4 4 -

Start U startu -

Segment seg -

Curve Type seg0type - ⊞ -

• Constant constant -

• Linear linear -

• Ease In easein -

• Ease Out easeout -

• Ease In Ease Out easeinout -

• Bezier bezier -

U seg0u -

Specify Start Value seg0specstartval -

Start Value seg0startval -

End Value seg0endval -

Alpha seg0alpha -

Beta seg0beta -

Slope in seg0slopein -

Slope Out seg0slopeout -

Parameters - Lookup Page

Apply Lookup applylookup -

Lookup Index Attribute lookupindexattr -

From Low High fromlow -

From High fromhigh -

To Low High tolow -

To High tohigh -

Extend Left and Right extendleft - ⊞ -

• Hold hold -

• Slope slope -

• Cycle cycle -

• Mirror mirror -

Extend Right extendright - ⊞ -

• Hold hold -

• Slope slope -

• Cycle cycle -

• Mirror mirror -

Lookup lookup -

Multiply lookup0multiply -

Add lookup0add -

Combine Operation lookup0combineop - ⊞ -

• Set set -

• Add add -

• Multiply mult -

• Minimum min -

• Maximum max -

Output Attribute Scope lookup0outputattrscope - ⊞ -

• P P -

• N N -

• Color Color -

• Color.i012 Color.i012 -

• Tex Tex -

• PointScale PointScale -

• LineWidth LineWidth -

Override Automatic Attribute lookup0overrideautoattr -

New Attribute Type lookup0newattrtype - ⊞ -

• float float -

• double double -

• int int -

• uint uint -

• dir dir -

• dbl dir ddir -

New Attribute Number of Components lookup0attrnumcomps - ⊞ -

• 1 1 -

• 2 2 -

• 3 3 -

• 4 4 -

New Attribute Default Value lookup0newattrdefaultval - ⊞ -

• New Attribute Default Value lookup0newattrdefaultval1 -

• New Attribute Default Value lookup0newattrdefaultval2 -

• New Attribute Default Value lookup0newattrdefaultval3 -

• New Attribute Default Value lookup0newattrdefaultval4 -

Parameters - Common Page

Bypass bypass -

Delete Input Attributes delinputattrs -

Parameter Color Space parmcolorspace - ⊞ - Controls how all color parameters on this node are interpreted. The color values as treated as being in the selected color space, and are converted to the Working Color Space before they are used as part of the node's operation. Note that this does not change the color space of the node itself, as that is always in the Working Color Space.

• sRGB srgb - sRGB color space, with sRGB transfer function. Considered an SDR color space with respect to Reference White.

• sRGB - Linear srgblinear - sRGB color space, with linear transfer function. Considered an SDR color space with respect to Reference White.

• Rec.601 (NTSC) rec601ntsc - Rec.601 with NTSC primaries color space, with Rec.601 transfer function. Considered an SDR color space with respect to Reference White.

• Rec.709 rec709 - Rec.709 color space, with Rec.709 (same as Rec.2020) transfer function. Considered an SDR color space with respect to Reference White.

• Rec.2020 rec2020 - Rec.2020 color space, with Rec.2020 (same as Rec.709) transfer function. Considered an HDR color space with respect to Reference White.

• DCI-P3 dcip3 - DCI-P3 color space, with D65 white point and 2.6 gamma transfer function. Considered an HDR color space with respect to Reference White.

• DCI-P3 (D60) dcip3d60 - DCI-P3 "D60 sim" color space, with D60 white point, and 2.6 gamma transfer function. Considered an HDR color space with respect to Reference White.

• Display-P3 (D65) displayp3d65 - Display-P3 color space, with D65 white point, and sRGB gamma transfer function. Considered an HDR color space with respect to Reference White.

• ACES2065-1 aces2065-1 - ACES 2065-1 (also known as ACES AP0) color space, with a linear gamma transfer function. Considered an HDR color space with respect to Reference White.

• ACEScg acescg - ACEScg (also known as ACES AP1) color space, with a linear gamma transfer function. Considered an HDR color space with respect to Reference White.

• Passthrough passthrough - When selected, the color values will be used as-is in the operation, without any modification or attempt to convert them into the Working Color Space.

Parameter Reference White parmreferencewhite - ⊞ - When converting a parameter color value to the Working Color Space, this controls how it should be treated with respect to Reference White. If the Working Color Space is the same Reference White, then no adjustment is done. If they are different, then the Reference White level (brightness) of this color will be adjusted to the range expected by the Working Color Space. For example if the project is set to have a SDR Reference White of 120 nits, and the HDR Reference White is 80 nits, then a color of (1, 1, 1), which is 120 nits in the SDR color space, will be converted to be (1.5, 1.5, 1.5), which is 120 nits still in the HDR Working Color Space.

• Default For Color Space default - Will use either the SDR or the HDR Reference White, based on the color space selected.

• Standard (SDR) sdr - Will treat the Parameter Color Space as SDR for it's reference white value.

• High (HDR) hdr - Will treat the Parameter Color Space as HDR for it's reference white value.

Operator Inputs

• Input 0: -

Info CHOP Channels

Extra Information for the Curve 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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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.

Information associated with SOP geometry. Points and primitives (polygons, NURBS, etc.) can have any number of attributes - position (P) is standard, and built-in optional attributes are normals (N), texture coordinates (uv), color (Cd), etc.

A Link. The grey dashed lines between nodes is a Reference or Link that indicates one operator is getting data from another operator from any Operator Family.

The grey dashed lines between nodes is a Reference (or Link). A Reference is (1) a Parameter Reference, a parameter in an OP that is a name or path to another operator, (2) a Node Reference, an expression in a parameter or DAT script that contains the name or path of another operator, (3) a DAT Cell Reference or (4) a CHOP Channel Reference.

A Link or Reference is a dashed line between nodes that represent other data flowing between nodes. Examples are CHOP Exports, node Paths in parameters, and expressions in parameters referencing CHOP channels, DAT tables and other nodes. In contrast is a Wire that connects nodes in the same Operator Family.

A parameter reference can be setup between any two parameters by putting an expression in one parameter that refers to another parameter. This creates a Link between the two parameters such that when one changes, the other will change automatically (known in other software as a "constraint").

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.