Scanning Technology Research Articles

Using Digital Methods to Work on an Existing Sculptural Object or One in The Process of Physical Fabrication

The report examines key aspects of using digital methods in working on sculptural objects, both existing and in progress. An analysis of current trends and the impact of technological advances in sculpture is presented, with a focus on 3D scanning and virtual modelling Digital methods and tools and software platforms and hardware technologies for scanning, modelling and virtual creation are explored. Through a review of real-world examples and research projects, the possibilities and advantages of digital technologies in sculpture are illustrated. It analyses the challenges that arise when using digital methods and highlights the importance of combining classical sculptural techniques and digital skills. Emphasising the importance of digital methods as tools that enrich and extend sculptural practice and create opportunities for achieving high quality and innovation in art.

Development of a Methodology for Obtaining Solid Models of Products That Are Objects of Reverse Engineering Using the Example of the Capstone Micro-GTU C 65

Currently, about a thousand micro gas turbine units of small and medium capacity are in operation in the Russian Federation, which are used as an autonomous power source at critical infrastructure facilities. During long-term operation, the component parts of the micro GTU may fail and require replacement or repair. The lack of spare parts and design documentation for their production makes it impossible to operate. As a way to solve the problem, the reverse engineering process can be used to produce components. One of the stages of reverse engineering is to determine the geometric parameters of the object. The fastest and most accurate way to obtain geometric characteristics in the reverse engineering process is 3D scanning. Three-dimensional scanning technology is used to obtain a solid 3D model of the prototype surface, based on which design documentation is subsequently developed. This article presents the results of a study of the influence of the parameters of the distance between polygonal grid points and the scanner exposure on the detailing of the outer surface and the geometric parameters of the resulting polygonal model. As a result of this study, the dependence of the final file size and the time spent on scanning and processing on the distance between the points of the polygonal grid and the model was established. Based on the dependence of the parameters, recommendations were obtained for choosing the distance between the points of the polygonal grid of laser 3D scanning. Also, after performing the stages of reverse engineering, the methodology for creating solid models and design documentation of parts of power equipment units using 3D scanning technology was improved.

Accuracy Assessment of Advanced Laser Scanner Technologies for Forest Survey Based on Three-Dimensional Point Cloud Data

Forests play a crucial role in carbon sequestration and climate change mitigation, offering ecosystem services, biodiversity conservation, and water resource management. As global efforts to reduce greenhouse gas emissions intensify, the demand for accurate spatial information to monitor forest conditions and assess carbon absorption capacity has grown. LiDAR (Light Detection and Ranging) has emerged as a transformative tool, providing high-resolution 3D spatial data for detailed analysis of forest attributes, including tree height, canopy structure, and biomass distribution. Unlike traditional manpower-intensive forest surveys, which are time-consuming and often limited in accuracy, LiDAR offers a more efficient and reliable solution. This study evaluates the accuracy and applicability of advanced LiDAR technologies—drone-mounted, terrestrial, and mobile scanners—for generating 3D forest spatial data. The results show that the terrestrial LiDAR achieved the highest precision for diameter at breast height (DBH) and tree height measurements, with RMSE values of 0.66 cm and 0.91 m, respectively. Drone-mounted LiDAR demonstrated excellent efficiency for large-scale surveys, while mobile LiDAR offered portability and speed but required further improvement in accuracy (e.g., RMSE: DBH 0.76 cm, tree height 1.83 m). By comparing these technologies, this study identifies their strengths, limitations, and optimal application scenarios, contributing to more accurate forest management practices and carbon absorption assessments.

Pore-scale modelling of particle migration in loose sandstone

During the development of loose sandstone reservoirs, the issue of production decline and bottomhole pressure reduction caused by particle migration is widespread, directly impacting well productivity. Understanding the mechanism of particle migration in sandstone and determining the main factors affecting this process are crucial for improving oilfield development. This study focuses on an offshore oilfield and utilizes real digital core models constructed through CT scanning technology. Numerical simulations of fluid-solid coupling were conducted using Fluent and EDEM software to establish a coupled particle-oil-water flow model. This model was employed to investigate particle blockage modes and the effects of particle size, concentration, and injection rate on particle migration in the reservoir. The results indicate that particle migration primarily occurs in two blockage modes: pinhole blockage and bridging blockage. In sandstone, particle retention rates are primarily controlled by particle size, with larger pore-to-particle size ratios leading to higher retention rates. Particle concentration and injection rate have relatively minor effects on the final retention rate. As for migration distance, particle size significantly influences migration, with larger pore-to-particle size ratios resulting in shorter migration distances. Under low concentration conditions, concentration has a minimal effect on migration distance. However, as the injection rate increases, migration distance also increases. In summary, this study clarifies the particle migration mechanisms and the key factors controlling migration in sandstone formations, providing valuable theoretical support for oilfield development.

3D Assessment of Mandibular Margin Morphological Change after BTX-A Injection for Masseter Hypertrophy: A Retrospective Study.

Some facial morphological changes may occur in some patients after botulinum toxin A (BTX-A) injection for the treatment of masseteric hypertrophy. The aim of this study was to investigate the morphological changes that occurred on mandibular margin. This retrospective analysis included 43 patients (86 lateral cases) who received BTX-A injections for masseter hypertrophy. To assess the morphological changes in the mandibular margin after treatment, the sharpness of the mandibular margin was evaluated before and after the injections using an established grading system. Additionally, 3D scanning technology was used to measure both the therapeutic effect of the BTX-A injections and the extent of soft tissue sagging in the mandibular margin area. Grading: The grade of mandibular margin sharpness change occurred in 41 lateral cases post-procedurally. Based on the measurement results, statistically significant differences were observed before, 1 month, and 3 months post-procedurally in subjects' positive lower face width representing the therapeutic effect of BTX-A injection and the extent of sagging soft tissue at sagittal section B and section C (p < 0.05), but not in section A (A: outer canthus, B: midpoint of the eyelid margin, and C: inner canthus) (p > 0.05). After receiving a BTX-A injection for masseteric hypertrophy, the mandibular margin may develop an unclear mandibular margin and sagging soft tissue in mandibular margin area. EBM Level: IV LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Effects of rainfall-induced physical crusts on soil carbon distribution and mineralization through surface pore structure

The vast carbon sequestration potential of soil implies that even minor changes in its characteristics can impact atmospheric carbon levels. However, little research has focused on the influence of rainfall-induced physical crusts, a common natural phenomenon, on soil organic carbon (SOC). In this study, we simulated contour farming patterns and induced artificial rainfall to obtain different types of physical crusts (structural and depositional crusts). We determined their effects on SOC mineralization rates and distribution and utilized XCT scanning technology to gather surface pore data, attempting to explain the reasons from the perspective of pore structure changes. The formation of physical crusts significantly enhanced SOC mineralization. During the 27-day mineralization experiment, the production of structural and depositional crusts increased cumulative mineralization rates by at least 23.07 % and 18.57 %, respectively. The underlying cause of this phenomenon is closely related to the drastic changes in soil pore structure, particularly the increase in the proportion of micropores and the enhancement of pore connectivity after crust cracking. Additionally, rainfall resulted in SOC enrichment in the surface crust but led to increased participation of subsoil organic carbon in the mineralization process. Consequently, the level of SOC in subsoil significantly decreased after the formation of physical crusts compared to soil without crusts. This study reveals the impact of rainfall-induced soil physical crusts on SOC release and storage and provides a microscopic pore perspective to explain the underlying mechanisms. Against the backdrop of global climate change, this research supplements theoretical understanding of the effects of rainfall events on soil carbon pools and predictions of soil organic carbon release.

A framework for phenotyping rubber trees under intense wind stress using laser scanning and digital twin technology

Rubber trees in coastal habitats are exposed to a high degree of wind stress. An algorithm-hardware synergetic methodology was developed for investigating and predicting rubber tree phenotyping excited by strong winds. The framework includes (1) a custom-designed industrial fan that recreates a variable airflow field at wind speeds of 15, 30 and 45 m/s coupled with a terrestrial laser scanner and bundled motion sensors to acquire point clouds and vibration data; (2) a graphic model that approximates tree canopies based on foliage clumps with phenotypic traits that are derived from point clouds captured while trees are subjected to aerodynamic drag; and (3) the wind characteristic parameters of forest canopies were calculated by a developed forest-specialized k-ε turbulence model combining the constructed tree models and grid-scale subdivision of the wind fluid field. (4) A digital twin model that incorporates detailed tree phenotypic traits and considers plant mechanical characteristics was established, depicting the related wind-induced actions of target trees under various wind influences. The results show that tree crowns with spreading forms are prone to yield larger pendulum amplitudes than compact crowns, but trees directly exposed to wind exhibit greater crown volume reductions than trees in sheltered areas. Within tree canopies, a one-fold increase in inlet wind speed intensified crown compression (approximately 17 % decrease in crown volume), generated 2.1-fold pressure gradients and increased turbulence kinetic energy by approximately 60 %. Moreover, the entire scenario of the adaptation of experimental trees to wind perturbations was visually restored using digital twin techniques, serving as an integral behaviour dataset for further data-driven decision-making. In summary, this paper presents a comprehensive methodology that can decipher the phenotypic manifestations of trees' reactions to wind hazards, with potential applications in phenotyping or envirotyping studies designed to evaluate the wind resistance properties of rubber trees.

Post‐earthquake structural damage identification and safety evaluation using point clouds

AbstractEfficient and accurate post‐earthquake damage assessment of building structures is critical for ensuring the human safety and structural integrity of affected buildings. However, manual inspections and traditional visual damage identification methods are often constrained by the inaccessibility of hard‐to‐reach regions and the subjectivity of human inspectors. To overcome these issues, this paper proposes a novel approach for rapid and precise post‐earthquake damage identification and evaluation using unmanned aerial vehicle (UAV) and point cloud techniques, significantly reducing the time, labor, and errors associated with traditional methods. A comprehensive testing on full‐scale reinforced concrete shear walls was conducted to validate the precision and feasibility of this method. The point cloud models of the shear wall were generated leveraging UAV imagery and laser scanning technology with millimeter‐scale accuracy. The proposed algorithm effectively segmented each target plane of the shear wall, achieving a relatively satisfactory overall Intersection over Union of 99.25%. The relative errors of deformation between the algorithm's identification and gauges measurements were within 5%. This study successfully segmented and quantified structural surface damage, including cracks and spalling. Finally, the structural safety of the shear wall was evaluated according to ATC‐20 guidelines, using indicators such as inclination, story drift ratio, crack width, and damage area. Furthermore, proposed method was also verified in real cases.

The Megafauna3D Educational Environment: Harnessing the Combination of New and Traditional Technologies to Improve Geoscience Education and Outreach

The Megafauna3D project integrates advanced 3D scanning technologies and paleontological research to bring the extinct megafauna of Uruguay to formal and informal educational settings. Through the use of digitized fossil models, interactive education materials, and a web platform, the project engages the public and educational institutions in understanding the country’s paleontological heritage. This manuscript presents Megafauna3D’s multidisciplinary approach, its outreach initiatives, and the educational resources developed, such as 3D models and printed replicas, a book integrated with augmented reality, fanzines, and a teaching box. With a focus on open science, inclusivity, and accessibility, the project fosters public engagement with paleontological content and promotes fossil heritage conservation.

Enhancing Effective Scanning Techniques for Digital Impression in Neonates with Cleft Lip and/or Palate: A Laboratory Study Investigating the Impact of Different Scanners, Scanning Tip Sizes, and Strategies

Background/Objectives: Digital impressions are increasingly used to manage Cleft lip and/or palate (CL/P), potentially offering advantages over traditional methods. This laboratory investigation sought to evaluate the impact of scanning tip sizes, different scanners, and scanning strategies on intraoral scanning in neonates with CL/P. Methods: Ten soft acrylic models were used to simulate the oral anatomy of neonates with CL/P, evaluating parameters such as the ability of different scanning tips to capture alveolar cleft depth, scanning time, number of scan stops, and scan quality. The study utilised various scanning tips, including the Carestream normal tip, Carestream side tip, and Trios 4 scanner tip to assess the alveolar cleft depth measurements. The Trios 4, Carestream, and iTero scanners were evaluated for the time taken, number of scan stops during cleft-unobstructed scanning and cleft-obstructed scanning. The quality of all scanned images was analysed. Results: The findings showed comparable accuracy in capturing alveolar cleft depth with the three-scanning tip (p &gt; 0.05). Scanning time and the number of scan stops did not significantly differ across the three scanners and various scanning strategies employed (p &gt; 0.05). However, scanning with the cleft obstructed required less time and resulted in fewer scan stops compared to cleft -unobstructed scanning. Despite these results, all scanners failed to record the deepest part of the alveolar cleft, highlighting a limitation in current scanning technology for neonates with CL/P. Conclusions: The study recommends enhancing intraoral scanning in this population by adjusting tip size, improving clinician training, optimizing protocols, and conducting further research to improve techniques.

Spatial distribution of soil pore structure and response characteristics of physical parameters in the subsidence area induced by shallow-buried extra-thick coal seam mining

The development of ground fissures in the subsidence area induced by shallow-buried extra-thick coal seam mining leads to a decrease in soil water-holding capacity and vegetation withering. The investigation of the spatial distribution characteristics of soil pore structure in mining-induced subsidence areas and the elucidation of the response mechanism between soil physical parameters and soil structure are essential prerequisites for achieving effective ecological environment protection and restoration in mining areas. In this study, three-dimensional visualization reconstruction of soil porosity, pore diameter, roundness rate and pore connectivity at different profile depths in subsidence area caused by ultra-thick coal seam mining was conducted by using the soil CT scanning technology. Additionally, a correlation analysis model was established between physical parameters such as soil moisture content, bulk density, and pore structure parameters. The results indicate that: (1) Compared to the non-subsidence area, the number, size, and proportion of soil pores significantly increase in the tension zone, compression zone, and neutral zone, and the pore network and connectivity are extensively interconnected, and the fissure development in the tension zone is most significant, and the soil pores in the subsidence compression zone are concentrated on one side due to the influence of soil deformation. (2) As the depth of the soil profile increases, the level of soil pore development significantly decreases. The large profile depth (40–100 cm) causes a significant decrease in pore development. (3) There is a significant correlation between soil pore structure parameters and soil physical parameters (P ≤ 0.05), a highly significant correlation between soil pore structure parameters and soil moisture content (P ≤ 0.01), and a highly significant correlation between soil texture and soil moisture content (P ≤ 0.01). This research is of great significance for guiding underground production layout and repairing damaged soil.

Advanced Scanning Technology for Volume Change Measurement of Residual Soil

Weathering processes of rocks lead to the formation of residual soil layers, which are typically characterized by a deep groundwater table and a thick unsaturated zone. Hence, the calculation of a slope’s safety factor under the influences of climatic circumstances is a function of unsaturated characteristics, such as the soil–water characteristic curve (SWCC). To determine the SWCC, the volume of the soil specimen must be determined in order to compute the void ratio and degree of saturation. The drying processes of the soil specimen led to uneven soil volume change during laboratory SWCC testing, demanding the development of a soil shrinkage curve. Several methods for measuring soil volume change have been developed over the years. However, there are significant limitations, and it is rarely used due to the difficulty linked to accurately measuring the soil volume during drying processes. In this study, a revised scanning approach is developed to evaluate residual soil volume change utilizing 3D scanning technology. The proposed method is applied in a case study on residual soil from the Old Alluvium in Singapore. The laboratory data and analysis results suggested that 3D scanning technology should be required to provide a correct estimation of the air-entry value of soil.

Enhancing 3D-Printed Clay Models for Heritage Restoration Through 3D Scanning

Recent development of methodologies based on digital twins through 3D scanning and 3D printing has increased over the past decade, offering new possibilities in manufacturing, production and scaling of models’ applications. However, there are few examples of the application of model digitization technologies for the restoration of ceramic-built heritage by means of 3D modelling. That is why this research focuses on the application of these advanced methodologies to the recovery of architectural ceramic ornamental objects in heritage buildings. Deteriorated ceramic pieces are selected and scanned during field campaigns using 3D scanning technology in early 20th century heritage sites in Seville (Spain). The aim is to create accurate replicas of these damaged objects by 3D printing with clay using non-invasive techniques. The study stands out for its practical approach and its implications for the conservation of built cultural heritage. The results proved effective for replacing lost or damaged elements in a heritage context. Once the investment in the necessary equipment and technologies has been made, the use of clay as a material for 3D printing not only proves feasible but also offers advantages in terms of cost and time savings for repairs compared to traditional restoration techniques. In the present investigation the production time of similar pieces using 3D printing took 6.3–10.9 h while traditional methods take over a week. The application of these technologies represents an advancement in integrating modern methods into cultural heritage conservation, opening new possibilities for the preservation of history and art worldwide.

Lithium Iron Phosphate Battery Failure Under Vibration

The failure mechanism of square lithium iron phosphate battery cells under vibration conditions was investigated in this study, elucidating the impact of vibration on their internal structure and safety performance using high-resolution industrial CT scanning technology. Various vibration states, including sinusoidal, random, and classical impact modes, were tested to simulate real-world usage scenarios. The findings demonstrate that different vibration conditions exert varying degrees of influence on the battery cells. Despite experiencing slight deformation and displacement after exposure to vibrations, their overall performance remains stable, with no significant safety hazards detected. Moreover, it was observed that while the side gap increases due to the partial absorption of impact load by both the battery cells and connection components, the bottom gap remains unchanged. This study holds immense significance in enhancing electric vehicle safety and reliability, while providing a scientific foundation for future optimization designs of lithium iron phosphate batteries.

Road boundary extraction method from mobile laser scanning point clouds

Abstract With the rapid development of mobile laser scanning (MLS) technology, high-precision three-dimensional point cloud data has shown great potential in different fields such as topographic mapping, road asset management and smart city construc-tion. Three-dimensional point cloud data contains not only position information, but also the shape and attributes of the target, which is very convenient for obtaining road information. Accurate extraction of the road boundary is a basic task for obtaining road infrastructural data, which can support the generation of high-precision maps, vehicle navigation and auton-omous driving. However, road boundary extraction in urban environments is easily occluded such as vehicles and pedestri-ans on the road, which leads to problems such as difficulty and incomplete extraction of MLS point cloud road boundaries. To address this problem, this study proposes a road boundary extraction method that integrates pavement edge information, accurately considers the position of the road boundary from two dimensions, eliminates false boundaries, and completes the missing boundary through the extracted boundary spatial relationship. First, grid elevation filtering is used to remove high-level non-ground points. Then the pavement edges and curb stone points are extracted from the preprocessed point cloud, and they are superimposed to remove false boundary points to obtain accurate road boundaries. Finally, based on the spatial relationship of road boundaries, missing parts are detected and repaired to obtain complete road boundaries. Experimental results show that the accuracy on real road scenes exceeds 98%, the completeness rate is above 91%, and the extraction quality is above 90%, which verifies the effectiveness and accuracy of this method.

Design and analysis of terrestrial laser scanner based on a 3-SPR parallel mechanism for improved anti-occlusion scanning

Abstract Laser scanner technology swiftly captures point cloud data of objects and their surrounding environments, proving extensive applications across various sectors. However, it often encounters challenges related to incomplete point clouds due to occlusion from stationary objects. This paper presents a terrestrial laser scanning system based on a 3-SPR (3-Spherical Joint-Active Prismatic Joint-Rotating Joint) parallel mechanism (TLS-PM), specifically designed to enhance scanning coverage during single-station measurements, reduce positioning and workload during multi-station measurements, and mitigate point cloud gaps caused by occlusions.&amp;#xD;Initially, a simulation model of the TLS-PM was developed, and both forward and inverse kinematic analysis were performed. Subsequently, the workspace was computed for different spherical joints using this model. An introduction to the TLS-PM’s error and the registration algorithm employed was then provided. Finally, through comparative analysis of simulations and experimental results, the device's measurement accuracy and its capability to resist occlusions were validated. Additionally, the TLS-PM’s anti-occlusion performance was evaluated under various scenarios in a simulated setting. The experimental results demonstrate that, when employing the same conventional point cloud processing algorithms, the TLS-PM significantly improves the background scanning coverage.

Dokładność modelu BIM z chmury punktów dla obiektu wykonanego w technologii szklanej

Mapping glass objects in 3D space has long raised doubts as to the possibility of obtaining data, and as to the accuracy of that data. The basics of terrestrial laser scanning technology and the principles of the physics of light propagation in the environment of transparent and reflective surfaces, as a rule, contradict the technological possibility of a faithful mapping thereof. Although Building Information Modelling (BIM) of existing objects based on data from terrestrial laser scanning is an increasingly common practice, it is recognized, nevertheless, that the accuracy of the model is primarily reflected in the accuracy of the point cloud obtained as a result of scanning. The article discusses the possibilities of developing a BIM model of an object made in glass technology, based on data obtained with the method of terrestrial laser scanning. The subject of the study was the glazed façade of the complex of buildings belonging to the University of Agriculture in Krakow. The study on the fidelity of mapping glazed surfaces included the acquisition and processing of the point cloud, 3D modelling of the object using the Revit software, and the analysis of the accuracy of mapping the existing status in comparison with architectural design and construction documentation. Based on the research, the possibility of using the BIM process was assessed using TLS data in the process of recreating the geometry of an object made in glass technology. The results of the study showed a significant convergence of the façade model geometry with the actual course of the structure, which, however, can be attributed to the development methodology, i.e. the accuracy of 3D data acquisition, the registration process, the filtration procedure, the method of parametric modelling of the façade structure itself, and ultimately fitting three-layer glazing into the model of that structure.

Random generation of three-dimensional realistic ballast particles using generative adversarial networks

Natural ballast particles exhibit a wide array of shape characteristics and follow complex probability distributions, which are difficult to quantify using explicit formulas due to their implicit nature. Traditional methods for generating ballast particles are limited to shapes that adhere to specific shape indices. In this study, generative adversarial networks (GANs) were utilized to randomly generate realistic three-dimensional (3D) ballast particles. Representative ballast particle shapes were captured using 3D structured light scanning technology. The scanned shapes were then voxelized and augmented to create a comprehensive dataset representing various ballast particle shapes. This dataset served to train the generator and discriminator components of the GANs. The trained generator successfully produced 2,000 detailed 3D ballast particles. Further refinement of these particles was achieved using Gaussian blur, followed by the Laplace smoothing algorithms and marching cubes algorithm for surface reconstruction. The authenticity of the generated ballast particles was validated by comparing their shape indices with those of natural ballast particles, thus demonstrating the effectiveness of the trained GANs model. The generated ballast particles are suitable for use as templates in discrete element method (DEM) simulations, specifically for clumps and polyhedrons.

Framework and case study for the assembly accuracy prediction of prefabricated buildings using BIM and TLS

ABSTRACT Tolerance management in the Architecture, Engineering, and Construction (AEC) sector faces challenges due to a lack of systematic scientific methods and tools. Quality issues in construction, coupled with inefficiencies, rework, and waste arising from deviation problems, hinder the sustainable development of the AEC sector. Current deviation control methods in the AEC field rely on compliance inspections and on-site rework, which are reactive and costly. In contrast, the manufacturing industry, closely linked to AEC, has developed highly automated methods for tolerance management. Although prefabricated buildings are manufactured off-site with high precision, the on-site assembly precision remains low, failing to fully leverage manufacturing industry capabilities. This research proposes a framework for predicting assembly accuracy of prefabricated buildings during the design and early construction stages. The framework, based on tolerance analysis methods from the manufacturing industry, integrates Building Information Modeling (BIM) and Terrestrial 3D Laser Scanning (TLS) technologies. This innovative approach offers a computer-aided method for conducting tolerance analysis in prefabricated buildings. A completed prefabricated building project serves as a case study, utilizing the framework to predict variations in critical dimensions, and the predictions align with measured results, demonstrating the feasibility of the proposed framework.

Micro-CT Analysis of Pore Structure in Upland Red Soil Under Different Long-Term Fertilization Regimes

This study hypothesized that long-term fertilization alters the pore structure and aggregate stability in upland red soil. A long-term fertilization experiment in Qiyang, Hunan, was conducted with three treatments: no fertilization (CK), nitrogen–phosphorus–potassium fertilization (NPK), and nitrogen–phosphorus–potassium combined with pig manure (NPKOM). X-ray computed tomography (CT) scanning technology was used to assess three-dimensional pore structures at both the soil column (50 mm diameter and 50 mm height) and aggregate scales (diameter 3–5 mm), alongside the evaluation of the soil’s physical and chemical properties. Results showed that the soil organic carbon content (SOC) increased by 44.8% in NPK and 112.5% in NPKOM compared to CK. NPKOM improved the aggregate stability by 51.6%, whereas NPK had no significant effect. At the soil column scale, NPK increased the total porosity by 13.7% but reduced larger pores (&gt;0.06 mm), whereas NPKOM decreased the total porosity by 7.8% and increased larger pores. At the aggregate scale, NPKOM increased the porosity for pores &gt;0.098 mm by 7.6 times compared to CK and 9.5 times compared to NPK. In conclusion, long-term NPKOM significantly enhances the SOC and aggregate stability and promotes larger pore formation, unlike NPK, which mainly increases SOC but does not improve the soil structure.