# Repair settings

Welding consists of merging vertices that are closer than a certain distance from each other. This is often used as a pre-processing step to make sure that the geometry is properly connected. Geometry information imported from file formats that do not use vertex indexing have to be welded or gaps between the triangles would be introduced when simplifying it. T-junction removal is also performed by the reducer processor as a pre-processing step. A T-junction is when a vertex is very close to an edge causing a small gap between the triangles. This is solved by splitting the edge at the projection of the vertex onto the edge and then then merging the two vertices.

The following figure shows the t-junction processing, before (left) and after (right).

T-junction

# Supported processors

Reduction processor

# Example

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

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

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


Simplygon::spScene LoadScene(Simplygon::ISimplygon* sg, const char* path)
{
	// Create scene importer 
	Simplygon::spSceneImporter sgSceneImporter = sg->CreateSceneImporter();
	sgSceneImporter->SetImportFilePath(path);
	
	// Run scene importer. 
	bool importResult = sgSceneImporter->RunImport();
	if (!importResult)
	{
		throw std::exception("Failed to load scene.");
	}
	Simplygon::spScene sgScene = sgSceneImporter->GetScene();
	return sgScene;
}

void SaveScene(Simplygon::ISimplygon* sg, Simplygon::spScene sgScene, const char* path)
{
	// Create scene exporter. 
	Simplygon::spSceneExporter sgSceneExporter = sg->CreateSceneExporter();
	sgSceneExporter->SetExportFilePath(path);
	sgSceneExporter->SetScene(sgScene);
	
	// Run scene exporter. 
	bool exportResult = sgSceneExporter->RunExport();
	if (!exportResult)
	{
		throw std::exception("Failed to save scene.");
	}
}

void CheckLog(Simplygon::ISimplygon* sg)
{
	// Check if any errors occurred. 
	bool hasErrors = sg->ErrorOccurred();
	if (hasErrors)
	{
		Simplygon::spStringArray errors = sg->CreateStringArray();
		sg->GetErrorMessages(errors);
		auto errorCount = errors->GetItemCount();
		if (errorCount > 0)
		{
			printf("%s\n", "Errors:");
			for (auto errorIndex = 0U; errorIndex < errorCount; ++errorIndex)
			{
				Simplygon::spString errorString = errors->GetItem((int)errorIndex);
				printf("%s\n", errorString.c_str());
			}
			sg->ClearErrorMessages();
		}
	}
	else
	{
		printf("%s\n", "No errors.");
	}
	
	// Check if any warnings occurred. 
	bool hasWarnings = sg->WarningOccurred();
	if (hasWarnings)
	{
		Simplygon::spStringArray warnings = sg->CreateStringArray();
		sg->GetWarningMessages(warnings);
		auto warningCount = warnings->GetItemCount();
		if (warningCount > 0)
		{
			printf("%s\n", "Warnings:");
			for (auto warningIndex = 0U; warningIndex < warningCount; ++warningIndex)
			{
				Simplygon::spString warningString = warnings->GetItem((int)warningIndex);
				printf("%s\n", warningString.c_str());
			}
			sg->ClearWarningMessages();
		}
	}
	else
	{
		printf("%s\n", "No warnings.");
	}
}

void RunReduction(Simplygon::ISimplygon* sg)
{
	// Load scene to process. 	
	printf("%s\n", "Load scene to process.");
	Simplygon::spScene sgScene = LoadScene(sg, "../../../Assets/SimplygonMan/SimplygonMan.obj");
	
	// Create the reduction processor. 
	Simplygon::spReductionProcessor sgReductionProcessor = sg->CreateReductionProcessor();
	sgReductionProcessor->SetScene( sgScene );
	Simplygon::spReductionSettings sgReductionSettings = sgReductionProcessor->GetReductionSettings();
	Simplygon::spRepairSettings sgRepairSettings = sgReductionProcessor->GetRepairSettings();
	
	// 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 number of repair passes. Higher value is slower but give better quality. 
	sgRepairSettings->SetProgressivePasses( 3 );
	
	// Enable vertex welding. 
	sgRepairSettings->SetUseWelding( true );
	sgRepairSettings->SetWeldDist( 0.0f );
	
	// Remove T-junktions. 
	sgRepairSettings->SetUseTJunctionRemover( true );
	sgRepairSettings->SetTJuncDist( 0.0f );
	
	// No restriction to the weld process. 
	sgRepairSettings->SetWeldOnlyBetweenSceneNodes( false );
	sgRepairSettings->SetWeldOnlyBorderVertices( false );
	sgRepairSettings->SetWeldOnlyWithinMaterial( false );
	sgRepairSettings->SetWeldOnlyWithinSceneNode( false );
	
	// Start the reduction process. 	
	printf("%s\n", "Start the reduction process.");
	sgReductionProcessor->RunProcessing();
	
	// Save processed scene. 	
	printf("%s\n", "Save processed scene.");
	SaveScene(sg, sgScene, "Output.fbx");
	
	// Check log for any warnings or errors. 	
	printf("%s\n", "Check log for any warnings or errors.");
	CheckLog(sg);
}

int main()
{
	Simplygon::ISimplygon* sg = NULL;
	Simplygon::EErrorCodes initval = Simplygon::Initialize( &sg );
	if( initval != Simplygon::EErrorCodes::NoError )
	{
		printf( "Failed to initialize Simplygon: ErrorCode(%d)", (int)initval );
		return int(initval);
	}

	RunReduction(sg);

	Simplygon::Deinitialize(sg);

	return 0;
}

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

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

public class Program
{
    static Simplygon.spScene LoadScene(Simplygon.ISimplygon sg, string path)
    {
        // Create scene importer 
        using Simplygon.spSceneImporter sgSceneImporter = sg.CreateSceneImporter();
        sgSceneImporter.SetImportFilePath(path);
        
        // Run scene importer. 
        bool importResult = sgSceneImporter.RunImport();
        if (!importResult)
        {
            throw new System.Exception("Failed to load scene.");
        }
        Simplygon.spScene sgScene = sgSceneImporter.GetScene();
        return sgScene;
    }
    static void SaveScene(Simplygon.ISimplygon sg, Simplygon.spScene sgScene, string path)
    {
        // Create scene exporter. 
        using Simplygon.spSceneExporter sgSceneExporter = sg.CreateSceneExporter();
        sgSceneExporter.SetExportFilePath(path);
        sgSceneExporter.SetScene(sgScene);
        
        // Run scene exporter. 
        bool exportResult = sgSceneExporter.RunExport();
        if (!exportResult)
        {
            throw new System.Exception("Failed to save scene.");
        }
    }
    static void CheckLog(Simplygon.ISimplygon sg)
    {
        // Check if any errors occurred. 
        bool hasErrors = sg.ErrorOccurred();
        if (hasErrors)
        {
            Simplygon.spStringArray errors = sg.CreateStringArray();
            sg.GetErrorMessages(errors);
            var errorCount = errors.GetItemCount();
            if (errorCount > 0)
            {
                Console.WriteLine("Errors:");
                for (uint errorIndex = 0; errorIndex < errorCount; ++errorIndex)
                {
                    string errorString = errors.GetItem((int)errorIndex);
                    Console.WriteLine(errorString);
                }
                sg.ClearErrorMessages();
            }
        }
        else
        {
            Console.WriteLine("No errors.");
        }
        
        // Check if any warnings occurred. 
        bool hasWarnings = sg.WarningOccurred();
        if (hasWarnings)
        {
            Simplygon.spStringArray warnings = sg.CreateStringArray();
            sg.GetWarningMessages(warnings);
            var warningCount = warnings.GetItemCount();
            if (warningCount > 0)
            {
                Console.WriteLine("Warnings:");
                for (uint warningIndex = 0; warningIndex < warningCount; ++warningIndex)
                {
                    string warningString = warnings.GetItem((int)warningIndex);
                    Console.WriteLine(warningString);
                }
                sg.ClearWarningMessages();
            }
        }
        else
        {
            Console.WriteLine("No warnings.");
        }
    }
    static void RunReduction(Simplygon.ISimplygon sg)
    {
        // Load scene to process.         
        Console.WriteLine("Load scene to process.");
        Simplygon.spScene sgScene = LoadScene(sg, "../../../Assets/SimplygonMan/SimplygonMan.obj");
        
        // Create the reduction processor. 
        using Simplygon.spReductionProcessor sgReductionProcessor = sg.CreateReductionProcessor();
        sgReductionProcessor.SetScene( sgScene );
        using Simplygon.spReductionSettings sgReductionSettings = sgReductionProcessor.GetReductionSettings();
        using Simplygon.spRepairSettings sgRepairSettings = sgReductionProcessor.GetRepairSettings();
        
        // 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 number of repair passes. Higher value is slower but give better quality. 
        sgRepairSettings.SetProgressivePasses( 3 );
        
        // Enable vertex welding. 
        sgRepairSettings.SetUseWelding( true );
        sgRepairSettings.SetWeldDist( 0.0f );
        
        // Remove T-junktions. 
        sgRepairSettings.SetUseTJunctionRemover( true );
        sgRepairSettings.SetTJuncDist( 0.0f );
        
        // No restriction to the weld process. 
        sgRepairSettings.SetWeldOnlyBetweenSceneNodes( false );
        sgRepairSettings.SetWeldOnlyBorderVertices( false );
        sgRepairSettings.SetWeldOnlyWithinMaterial( false );
        sgRepairSettings.SetWeldOnlyWithinSceneNode( false );
        
        // Start the reduction process.         
        Console.WriteLine("Start the reduction process.");
        sgReductionProcessor.RunProcessing();
        
        // Save processed scene.         
        Console.WriteLine("Save processed scene.");
        SaveScene(sg, sgScene, "Output.fbx");
        
        // Check log for any warnings or errors.         
        Console.WriteLine("Check log for any warnings or errors.");
        CheckLog(sg);
    }
    static int Main(string[] args)
    {
        using var sg = Simplygon.Loader.InitSimplygon(out var errorCode, out var errorMessage);
        if (errorCode != Simplygon.EErrorCodes.NoError)
        {
            Console.WriteLine( $"Failed to initialize Simplygon: ErrorCode({(int)errorCode}) {errorMessage}" );
            return (int)errorCode;
        }
        RunReduction(sg);

        return 0;
    }
}

# 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 LoadScene(sg: Simplygon.ISimplygon, path: str):
    # Create scene importer 
    sgSceneImporter = sg.CreateSceneImporter()
    sgSceneImporter.SetImportFilePath(path)
    
    # Run scene importer. 
    importResult = sgSceneImporter.RunImport()
    if not importResult:
        raise Exception('Failed to load scene.')
    sgScene = sgSceneImporter.GetScene()
    return sgScene

def SaveScene(sg: Simplygon.ISimplygon, sgScene:Simplygon.spScene, path: str):
    # Create scene exporter. 
    sgSceneExporter = sg.CreateSceneExporter()
    sgSceneExporter.SetExportFilePath(path)
    sgSceneExporter.SetScene(sgScene)
    
    # Run scene exporter. 
    exportResult = sgSceneExporter.RunExport()
    if not exportResult:
        raise Exception('Failed to save scene.')

def CheckLog(sg: Simplygon.ISimplygon):
    # Check if any errors occurred. 
    hasErrors = sg.ErrorOccurred()
    if hasErrors:
        errors = sg.CreateStringArray()
        sg.GetErrorMessages(errors)
        errorCount = errors.GetItemCount()
        if errorCount > 0:
            print("Errors:")
            for errorIndex in range(errorCount):
                errorString = errors.GetItem(errorIndex)
                print(errorString)
            sg.ClearErrorMessages()
    else:
        print("No errors.")
    
    # Check if any warnings occurred. 
    hasWarnings = sg.WarningOccurred()
    if hasWarnings:
        warnings = sg.CreateStringArray()
        sg.GetWarningMessages(warnings)
        warningCount = warnings.GetItemCount()
        if warningCount > 0:
            print("Warnings:")
            for warningIndex in range(warningCount):
                warningString = warnings.GetItem(warningIndex)
                print(warningString)
            sg.ClearWarningMessages()
    else:
        print("No warnings.")

def RunReduction(sg: Simplygon.ISimplygon):
    # Load scene to process.     
    print("Load scene to process.")
    sgScene = LoadScene(sg, "../../../Assets/SimplygonMan/SimplygonMan.obj")
    
    # Create the reduction processor. 
    sgReductionProcessor = sg.CreateReductionProcessor()
    sgReductionProcessor.SetScene( sgScene )
    sgReductionSettings = sgReductionProcessor.GetReductionSettings()
    sgRepairSettings = sgReductionProcessor.GetRepairSettings()
    
    # 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 number of repair passes. Higher value is slower but give better quality. 
    sgRepairSettings.SetProgressivePasses( 3 )
    
    # Enable vertex welding. 
    sgRepairSettings.SetUseWelding( True )
    sgRepairSettings.SetWeldDist( 0.0 )
    
    # Remove T-junktions. 
    sgRepairSettings.SetUseTJunctionRemover( True )
    sgRepairSettings.SetTJuncDist( 0.0 )
    
    # No restriction to the weld process. 
    sgRepairSettings.SetWeldOnlyBetweenSceneNodes( False )
    sgRepairSettings.SetWeldOnlyBorderVertices( False )
    sgRepairSettings.SetWeldOnlyWithinMaterial( False )
    sgRepairSettings.SetWeldOnlyWithinSceneNode( False )
    
    # Start the reduction process.     
    print("Start the reduction process.")
    sgReductionProcessor.RunProcessing()
    
    # Save processed scene.     
    print("Save processed scene.")
    SaveScene(sg, sgScene, "Output.fbx")
    
    # Check log for any warnings or errors.     
    print("Check log for any warnings or errors.")
    CheckLog(sg)

if __name__ == '__main__':
    sg = simplygon_loader.init_simplygon()
    if sg is None:
        exit(Simplygon.GetLastInitializationError())

    RunReduction(sg)

    sg = None
    gc.collect()

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