Measure Distortion SOP

Overview

A sop for analysing the distortion introduced by geometry deformation sops.  The attributes it creates can then be used to add procedural smoothing to the geometry.  This is very useful for correcting sharp corners created in character defomation.

Usage

Input 1 is the deforming polygonal geometry.  Input 2 is the same geometry before deformation.

Parameters

User mask attribute A user supplied attribute in the range 0-1 that masks the created distortion attribute.
Method Which calculations to include in the final outputted distortion attribute.
Edge Length Compares the lengths of edges in the deforming geometry with the rest geometry.
Edge Angle Compares the angles of edges in the deforming geometry with the rest geometry.
Edge Length and Angle Both of the above.
Shortening edges only When comparing edge lengths only concider the ones that get shorter.
Normalise length ratios Fit the edge length changes between 0-1. Zero is no length change, 1 is the point with edges changing the most.
Max length ratio If normalising is off then this cuts the result and then re-normalises the values.
Use cusp angles When comparing angles compare angles between faces as well as angles between edges.
Normalise angle changes Fit the edge length changes between 0-1. Zero is no angle change, 1 is the point with edges changing the most.
Max angle changes If normalising is off then this cuts the result and then re-normalises the values.
Distortion attribute The name of the final output attribute.
Normalise distortion attribute Fit the distortion between 0-1. Zero is no distortion, 1 is the point with most distortion.
Add component attributes Add attributes for each calculated component.
Length ratio attribute The name of the added attribute showing edge length changes.
Edge angle attribute The name of the added attribute showing edge angle changes.
Cusp angle attribute The name of the added attribute showing face angle changes.
Visualise distortion Add colour to the geometry to show the distortion attribute.  Blue is no distortion and red is maximum distortion.