## Abstract  
Augmented reality (AR) is a relevant technology, which has demonstrated to be efficient for several applications, especially in the architecture, engineering, construction and operation (AECO) domain, where the integration of building information modeling (BIM) and AR has proved to be optimal in handling construction projects. However, the main challenge when integrating a virtual 3D model in an AR environment is the lack of precision and accuracy of placement that can occur between the real and the virtual environments. Although methods for placement via AR have been reported in the literature, there is a lack of investigations addressing their evaluation. Therefore, this paper proposes a methodology to perform a quantitative and qualitative assessment of several AR placement methods and a discussion about their usability in the specific context of AECO. We adopt root mean square error (RMSE) to quantify the placement accuracy of a 3D model and standard deviation to examine its stability (jittering). The results revealed that the AR placement error range is extremely wide (from a few centimeters up to meters). In marker-based methods, the results showed centimeter-range in both indoor and outdoor environments, compared to other methods (Inertial, Marker-less, etc. ), while marker-less methods have widely varying error range from centimeters to a few meters. Other commercial solutions based on placement-sensors (GNSS and IMU), such as Trimble SiteVision, have proven placement performance in manual mode with centimeter order, while for the automatic mode, the order of placement and stability is metric, due to the low coverage of RTX (real time extended) in the study area. a 2022 17 October 2022 2022 2022 2022 2022 2022 2022 2022 2022 2022 22022 2022 22022 22022 2202  
issues in AR is the placement problem, which relates to the spatial misalignment of the real world and the AR environment. The inaccuracy of sensors on mobile platforms such as smartphones and tablets, calculating the characteristics of the camera position, and the placement method used are the major causes behind this [10]. For many applications where accuracy is critical, determining the degree of misalignment of the objects represented on the screen by calculating distances in the 3D world coordinate system is required. In this context, [PERSON]. [11] presented a reproducible methodology for having the real distances between any real point and the lines of sight of its virtual projections, for any AR application. [PERSON]. [12] proposed a method to assess the accuracy of the outdoor AR for underground utility mapping solutions. The main goal of this study was to create a mobile-based AR-geographic information system (GIS) for mapping and capturing underground utilities. A cloud-based system allows for the immediate sharing of data with other stakeholders. The authors concluded that smartphone accuracy is limited; alternatively, they used external global navigation satellite system (GNSS) devices to reduce positional errors. Several AR placement methods have been proposed in the literature. Furthermore, many authors [12; 13; 14] have addressed the AR placement issue. However, we note a lack of studies assessing the existing approaches and methods of 3D model placement in an AR environment. This motivated us to conduct research in this field. The main contributions of our paper are fourfold:  
* Propose a workflow for assessing placement methods of a 3D model in an AR environment;
* Study the influencing factors of some placement methods;
* Assess placement methods in terms of accuracy and stability;
* Discuss the applicability of the studied placement methods in the AECO domain. To achieve these objectives, the reminder of this paper is organized as follows: Section 2 reviews AR placement methods and solutions proposed in the literature. Section 3 describes the assessment approach. Section 4 presents the experimental tests, followed by Section 5, in which we present all results obtained by the qualitative and quantitative assessment.