Line Metrics POP
Summary
You can add metrics attributes to Line Strips. They can be created as point attribute or the vertex attributes.
This gives good information about the points and the context they are in. For each point you can get the direction to the next and previous points, or the distance back to the start of the line strip, or the line strip number it is in… things useful for Math POPs or Lookup POPs.
A convenience of the Line Metrics POP is to give nice values to awkward situations like co-incident points (two or more consecutive points in the same location), especially direction vectors. That’s what the Continuous Direction parameter does. It would work with Direction to Next, Direction to Previous, and do nice things to the Tangent vectors by keeping them in line.
Parameters - Neighbor Page
Attribute Class
attrclass - ⊞ - Makes the POP operate on point attributes, vertex attributes or primitive attributes where applicable.
- Point
point-
- Vertex
vertex-
Displacement to Next
dispnext - ⊞ - Whether to output an attribute with the displacement to the next vertex in the line strip.
- Displacement to Next
dispnext-
- Displacement to Next Attrib Name
dispnextname- Specifies the attribute scope used to output the Displacement to Next attribute
Displacement to Previous
dispprev - ⊞ - Whether to output an attribute with the displacement to the previous vertex in the line strip.
- Displacement to Previous
dispprev-
- Displacement to Previous Attrib Name
dispprevname- Specifies the attribute scope used to output the Displacement to Previous attribute
Distance to Next
distnext - ⊞ - Whether to output an attribute with the distance to the next vertex in the line strip.
- Distance to Next
distnext-
- Distance to Next Attrib Name
distnextname- Specifies the attribute scope used to output the Distance to Next attribute
Distance to Previous
distprev - ⊞ - Whether to output an attribute with the distance to the previous vertex in the line strip.
- Distance to Previous
distprev-
- Distance to Previous Attrib Name
distprevname- Specifies the attribute scope used to output the Distance to Previous attribute
Direction to Next
dirnext - ⊞ - Whether to output an attribute with the direction to the next vertex in the line strip.
- Direction to Next
dirnext-
- Direction to Next Attrib Name
dirnextname- Specifies the attribute scope used to output the Direction to Next attribute
Direction to Previous
dirprev - ⊞ - Whether to output an attribute with the direction to the previous vertex in the line strip.
- Direction to Previous
dirprev-
- Direction to Previous Attrib Name
dirprevname- Specifies the attribute scope used to output the Direction to Previous attribute
Tangent
tangent - ⊞ - Output a tangent attribute for each point.
- Tangent
tangent-
- Tangent Attrib Name
tangentname- Attribute scope for the tangent.
Curvature
curvature - ⊞ - Whether to output an attribute containing the curvature.
- Curvature
curvature-
- Curvature Attrib Name
curvaturename- Sets the attribute scope when computing curvature
Angle per Distance
angleperdist - ⊞ - Whether to output Angle per Distance.
- Angle per Distance
angleperdist-
- Angle per Distance Attrib Name
angleperdistname- Attribute Name for Angle per Distance.
Continuous Direction
continuousdir - Enable returning continuous directions for co-incident points
Max Neighbors
maxneighbors - When computing Direction vector, how far to look when points are in same position as next or previous points.
Parameters - Line Strip Page
Distance from Start
diststart - ⊞ - Whether to output an attribute with the distance from the start of the line strip.
- Distance from Start
diststart-
- Distance from Start Attrib Name
diststartname- Specifies the attribute scope used to output the Distance from Start attribute
Distance from End
distend - ⊞ - Whether to output an attribute with the distance from the end of the line strip.
- Distance from End
distend-
- Distance from End Attrib Name
distendname- Specifies the attribute scope used to output the Distance from End attribute
Distance from Start Normalized
diststartnorm - ⊞ - Whether to output an attribute with the normalized distance from the start of the line strip.
- Distance from Start Normalized
diststartnorm-
- Distance from Start Normalized Attrib Name
diststartnormname- Specifies the attribute scope used to output the Distance from Start Normalized attribute
Distance from End Normalized
distendnorm - ⊞ - Whether to output an attribute with the normalized distance from the end of the line strip.
- Distance from End Normalized
distendnorm-
- Distance from End Normalized Attrib Name
distendnormname- Specifies the attribute scope used to output the Distance from End Normalized attribute
Line Strip Length
primlen - ⊞ - Enable addition of line strip length attribute.
- Line Strip Length
primlen-
- Line Strip Length Attrib Name
primlenname- Name of the attribute for the line strip length.
Length Attrib Primitive Attribute
primlenprim - When on, the attribute created for the length of the line strip is a primitive attribute.
Parameters - Index Page
Vert Index in Line Strip
pointindex - ⊞ - Output the vertex index for each point, assuming unique.
- Vert Index in Line Strip
pointindex-
- Vert Index Attrib Name
pointindexname- The name of the vertex index attribute.
Number of Verts in Line Strip
numverts - ⊞ - Outputs attribute for number of vertices in current point's like strip.
- Number of Verts in Line Strip
numverts-
- Number of Verts Attrib Name
numvertsname- Name for the Number of Verts in Line Strip attribute.
Vert Index in Line Strip Normalized
vertindexnorm - ⊞ - Output the vertex index normalized to 0-1 for each point, assuming unique.
- Vert Index in Line Strip Normalized
vertindexnorm-
- Vert Index Normalized Attrib Name
vertindexnormname- The name of the vertex index normalized attribute.
Line Strip Index
linestripindex - ⊞ - Enable addition of line strip index attribute.
- Line Strip Index
linestripindex-
- Line Strip Index Attrib Name
linestripindexname- Attribute name for the index of the line strip.
Line Strip Index Normalized
lsindexnorm - ⊞ - Enable addition of normalized line strip index attribute.
- Line Strip Index Normalized
lsindexnorm-
- Line Strip Index Normalized Attrib Name
lsindexnormname- Attribute name for the normalized index of the line strip.
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 Line Metrics POP can be accessed via an Info CHOP.
Common POP Info Channels
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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