Reduction using ReductionProcessor ​

import maya.cmds as cmds
from simplygon10 import simplygon_loader
from simplygon10 import Simplygon
import gc

def run_reduction (sg):
    # Set Maya's handedness setting
    sg.SetGlobalDefaultTangentCalculatorTypeSetting(Simplygon.ETangentSpaceMethod_OrthonormalRightHanded)

    # Load the scene from file
    lodScene = sg.CreateScene()
    lodScene.LoadFromFile('D:/Assets/ExportedScene.sb')

    # Create the reduction-processor, and set which scene to reduce
    reductionProcessor = sg.CreateReductionProcessor()
    reductionProcessor.SetScene(lodScene)

    # The reduction settings object contains settings pertaining to the actual decimation
    reductionSettings = reductionProcessor.GetReductionSettings()

    # Try, when possible to reduce symmetrically
    reductionSettings.SetKeepSymmetry(True)

    # Auto-detect the symmetry plane, if one exists. Can, if required, be set manually instead
    reductionSettings.SetUseAutomaticSymmetryDetection(True)

    # Drastically increases the quality of the LODs normals, at the cost of extra processing time
    reductionSettings.SetUseHighQualityNormalCalculation(True)

    # Choose between "fast" and "consistent" processing
    reductionSettings.SetReductionHeuristics(
        Simplygon.EReductionHeuristics_Consistent)

    # The reduction stops when any of the targets below is reached
    reductionSettings.SetReductionTargetStopCondition(Simplygon.EStopCondition_Any)

    # Selects which targets should be considered when reducing
    reductionSettings.SetReductionTargetTriangleRatioEnabled(True)
    reductionSettings.SetReductionTargetTriangleCountEnabled(True)
    reductionSettings.SetReductionTargetMaxDeviationEnabled(True)
    reductionSettings.SetReductionTargetOnScreenSizeEnabled(True)

    # Targets at 50% of the original triangle count
    reductionSettings.SetReductionTargetTriangleRatio(0.5)

    # Targets when only 10 triangle remains
    reductionSettings.SetReductionTargetTriangleCount(10)

    # Targets when an error of the specified size has been reached. As set here it never happens
    reductionSettings.SetReductionTargetMaxDeviation(1e27)

    # Targets when the LOD is optimized for the selected on screen pixel size
    reductionSettings.SetReductionTargetOnScreenSize(50)

    # The repair settings object contains settings to fix the geometries
    repairSettings = reductionProcessor.GetRepairSettings()
    repairSettings.SetTJuncDist(0.0)  # Removes t-junctions with distance 0.0f
    repairSettings.SetWeldDist(0.0)  # Welds overlapping vertices

    # The normal calculation settings deal with the normal-specific reduction settings
    normalSettings = reductionProcessor.GetNormalCalculationSettings()

    # If True, this will turn off normal handling in the reducer and recalculate them all
    # afterwards instead.
    normalSettings.SetReplaceNormals(False)

    # Run the actual processing.
    # After this, the set geometry will have been reduced according to the settings
    reductionProcessor.RunProcessing()

    # Save the processed scene to file
    lodScene.SaveToFile('D:/Assets/ProcessedScene.sb')

# Load Maya scene
cmds.file(f=True, new=True)
cmds.file('D:/Assets/MyScene.fbx', i=True, mergeNamespacesOnClash=True,
          namespace=':', importFrameRate=True)

# Clear previous export mapping
bResult = cmds.Simplygon(cgm=True)

# Select all objects
cmds.select(all=True)

# Export scene to file
bResult = cmds.Simplygon(exp='D:/Assets/ExportedScene.sb', cte=False)

# Initialize Simplygon
sg = simplygon_loader.init_simplygon()

# Run reduction
run_reduction(sg)

# Import processed file into Maya, LOD-index = 1, CopyTextures = False, LinkMaterials = True
bResult = cmds.Simplygon(imp='D:/Assets/ProcessedScene.sb',
                         cte=False, lma=True, mnf="My_{MeshName}_LOD{LODIndex}", ili=1)

# De-initialize Simplygon
sg = None
gc.collect()