Normal calculation settings

After reduction has completed, the reducer can optionally generate new normals on the reduced geometry. These settings control how these new normals are calculated.

Supported processors

• Reduction processor

Example - Use normal calculation settings

The following example shows how to use the normal calculation settings in the reducer.

Example

This example shows how to use the Reduction processor with normal calculation settings.

// Copyright (c) Microsoft Corporation. 
// Licensed under the MIT license. 

#include <string>
#include <stdlib.h>
#include <filesystem>
#include <future>
#include "SimplygonLoader.h"


void RunReduction(Simplygon::ISimplygon* sg)
{
	Simplygon::spSceneImporter sgSceneImporter = sg->CreateSceneImporter();
	sgSceneImporter->SetImportFilePath( "../Assets/SimplygonMan/SimplygonMan.obj" );
	if(!sgSceneImporter->RunImport())
		throw std::exception("Failed to load SimplygonMan/SimplygonMan.obj.");
	Simplygon::spScene sgScene = sgSceneImporter->GetScene();

	// Create the reduction processor. 
	Simplygon::spReductionProcessor sgReductionProcessor = sg->CreateReductionProcessor();

	sgReductionProcessor->SetScene( sgScene );

	Simplygon::spReductionSettings sgReductionSettings = sgReductionProcessor->GetReductionSettings();
	Simplygon::spNormalCalculationSettings sgNormalCalculationSettings = sgReductionProcessor->GetNormalCalculationSettings();

	// Set reduction target to triangle ratio with a ratio of 50%. 
	sgReductionSettings->SetReductionTargets( Simplygon::EStopCondition::All, true, false, false, false );
	sgReductionSettings->SetReductionTargetTriangleRatio( 0.5f );

	// The angle in degrees determing the normal smoothness. 
	sgNormalCalculationSettings->SetHardEdgeAngle( 75 );

	// Reorthogonalize the tangentspace after the reduction. 
	sgNormalCalculationSettings->SetReorthogonalizeTangentSpace( true );

	// Repair invalid normals. 
	sgNormalCalculationSettings->SetRepairInvalidNormals( true );

	// Don't generate new normals. However invalid normals will still be repaired. 
	sgNormalCalculationSettings->SetReplaceNormals( false );

	// Don't generate new tangents and bitangents. 
	sgNormalCalculationSettings->SetReplaceTangents( false );

	// Scale the vertex normal based on the triangle area. 
	sgNormalCalculationSettings->SetScaleByAngle( false );
	sgNormalCalculationSettings->SetScaleByArea( true );

	// Don't snap the normal to flat surfaces. 
	sgNormalCalculationSettings->SetSnapNormalsToFlatSurfaces( false );

	// Start the reduction process. 
	sgReductionProcessor->RunProcessing();

	Simplygon::spSceneExporter  sgSceneExporter = sg->CreateSceneExporter();
	sgSceneExporter->SetScene(sgScene);
	sgSceneExporter->SetExportFilePath( "ReductionOutput.fbx" );
	if(!sgSceneExporter->RunExport())
		throw std::exception("Failed to save ReductionOutput.fbx.");

}

void main()
{
	Simplygon::ISimplygon* sg = NULL;
	Simplygon::EErrorCodes initval = Simplygon::Initialize( &sg );
	if( initval != Simplygon::EErrorCodes::NoError )
	{
		return;
	}

	RunReduction(sg);

	Simplygon::Deinitialize(sg);
}

// Copyright (c) Microsoft Corporation. 
// Licensed under the MIT license. 

using System;
using System.IO;
using System.Threading.Tasks;

public class Program
{
    static void RunReduction(Simplygon.ISimplygon sg)
    {
        using (Simplygon.spSceneImporter sgSceneImporter = sg.CreateSceneImporter())
        {
            sgSceneImporter.SetImportFilePath( "../Assets/SimplygonMan/SimplygonMan.obj" );
            if(!sgSceneImporter.RunImport())
                throw new System.Exception("Failed to load SimplygonMan/SimplygonMan.obj.");
            Simplygon.spScene sgScene = sgSceneImporter.GetScene();

            // Create the reduction processor. 
            using (Simplygon.spReductionProcessor sgReductionProcessor = sg.CreateReductionProcessor())
            {
                sgReductionProcessor.SetScene( sgScene );

                using (Simplygon.spReductionSettings sgReductionSettings = sgReductionProcessor.GetReductionSettings())
                using (Simplygon.spNormalCalculationSettings sgNormalCalculationSettings = sgReductionProcessor.GetNormalCalculationSettings())
                {
                    // Set reduction target to triangle ratio with a ratio of 50%. 
                    sgReductionSettings.SetReductionTargets( Simplygon.EStopCondition.All, true, false, false, false );
                    sgReductionSettings.SetReductionTargetTriangleRatio( 0.5f );

                    // The angle in degrees determing the normal smoothness. 
                    sgNormalCalculationSettings.SetHardEdgeAngle( 75 );

                    // Reorthogonalize the tangentspace after the reduction. 
                    sgNormalCalculationSettings.SetReorthogonalizeTangentSpace( true );

                    // Repair invalid normals. 
                    sgNormalCalculationSettings.SetRepairInvalidNormals( true );

                    // Don't generate new normals. However invalid normals will still be repaired. 
                    sgNormalCalculationSettings.SetReplaceNormals( false );

                    // Don't generate new tangents and bitangents. 
                    sgNormalCalculationSettings.SetReplaceTangents( false );

                    // Scale the vertex normal based on the triangle area. 
                    sgNormalCalculationSettings.SetScaleByAngle( false );
                    sgNormalCalculationSettings.SetScaleByArea( true );

                    // Don't snap the normal to flat surfaces. 
                    sgNormalCalculationSettings.SetSnapNormalsToFlatSurfaces( false );

                }
                // Start the reduction process. 
                sgReductionProcessor.RunProcessing();

            }
            using (Simplygon.spSceneExporter sgSceneExporter = sg.CreateSceneExporter())
            {
                sgSceneExporter.SetScene(sgScene);
                sgSceneExporter.SetExportFilePath( "ReductionOutput.fbx" );
                if(!sgSceneExporter.RunExport())
                    throw new System.Exception("Failed to save ReductionOutput.fbx.");

            }
        }
    }
    static void Main(string[] args)
    {
        using (var sg = Simplygon.Loader.InitSimplygon(out var errorCode, out var errorMessage))
        {
            if (errorCode != Simplygon.EErrorCodes.NoError)
                return;
            RunReduction(sg);
        }
    }
}

# Copyright (c) Microsoft Corporation. 
# Licensed under the MIT license. 

import math
import os
import sys
import glob
import gc
import threading

from pathlib import Path
from simplygon import simplygon_loader
from simplygon import Simplygon


def RunReduction(sg: Simplygon.ISimplygon):
    sgSceneImporter = sg.CreateSceneImporter()
    sgSceneImporter.SetImportFilePath( '../Assets/SimplygonMan/SimplygonMan.obj' )
    if not sgSceneImporter.RunImport():
        raise Exception('Failed to load SimplygonMan/SimplygonMan.obj.')
    sgScene = sgSceneImporter.GetScene()

    # Create the reduction processor. 
    sgReductionProcessor = sg.CreateReductionProcessor()

    sgReductionProcessor.SetScene( sgScene )

    sgReductionSettings = sgReductionProcessor.GetReductionSettings()
    sgNormalCalculationSettings = sgReductionProcessor.GetNormalCalculationSettings()

    # Set reduction target to triangle ratio with a ratio of 50%. 
    sgReductionSettings.SetReductionTargets( Simplygon.EStopCondition_All, True, False, False, False )
    sgReductionSettings.SetReductionTargetTriangleRatio( 0.5 )

    # The angle in degrees determing the normal smoothness. 
    sgNormalCalculationSettings.SetHardEdgeAngle( 75 )

    # Reorthogonalize the tangentspace after the reduction. 
    sgNormalCalculationSettings.SetReorthogonalizeTangentSpace( True )

    # Repair invalid normals. 
    sgNormalCalculationSettings.SetRepairInvalidNormals( True )

    # Don't generate new normals. However invalid normals will still be repaired. 
    sgNormalCalculationSettings.SetReplaceNormals( False )

    # Don't generate new tangents and bitangents. 
    sgNormalCalculationSettings.SetReplaceTangents( False )

    # Scale the vertex normal based on the triangle area. 
    sgNormalCalculationSettings.SetScaleByAngle( False )
    sgNormalCalculationSettings.SetScaleByArea( True )

    # Don't snap the normal to flat surfaces. 
    sgNormalCalculationSettings.SetSnapNormalsToFlatSurfaces( False )

    # Start the reduction process. 
    sgReductionProcessor.RunProcessing()

    sgSceneExporter = sg.CreateSceneExporter()
    sgSceneExporter.SetScene(sgScene)
    sgSceneExporter.SetExportFilePath( 'ReductionOutput.fbx' )
    if not sgSceneExporter.RunExport():
        raise Exception('Failed to save ReductionOutput.fbx.')


if __name__ == '__main__':
    sg = simplygon_loader.init_simplygon()
    if sg is not None:

        RunReduction(sg)

    sg = None
    gc.collect()