Algorithms to Measure Area and Volume on 3D Face Models for Facial Surgeries

Abstract

The increased availability and affordability of 3D scanning technology due to recent advancements have made pre and post-operative analysis for facial surgeries more convenient and accurate through the use of 3D patient scans. However, to perform a more comprehensive analysis using area and volume measurements, it is necessary to develop new software tools that include the appropriate algorithms. Without the right algorithms, any software tool cannot perform its intended tasks effectively. In this study, we introduce two algorithms along with their open-source code to calculate the surface area and volume of a specific subsection of a 3D model. The first algorithm partitions the area/volume into smaller segmentations and applies raycasting to find the points on the face surface, and then finds an approximate measurement depending on the resolution selected. In contrast, the second algorithm utilizes the vertex information stored in the 3D model file to calculate the area and volume measurements for the designated region. The advantage of the second algorithm is that it examines every point in the model, resulting in the highest degree of precision possible. We have also used ChatGPT to generate the code for area/volume calculation and found that the logic of the ChatGPT-generated code is surprisingly similar to the second algorithm. We have presented the results of the measurements on certain regions of the face for both of the algorithms and compared the temporal performance of the algorithms.

Exploring the application of CHATGPT in plastic surgery: a comprehensive systematic review

“…Its potential within academic settings, extends to assisting in the generation of code for studying 3D facial models, as well as aiding in preparation for plastic surgery examinations. Few authors reported that correct code generation required human prompting various times 15 . Other than plastic surgery examination, ChatGPT's abilities have been previously tested against exams like USMLE 49 , in which it cleared the exam but did not score a high grade.…”

“…Topsakal et al; demonstrated that ChatGPT is capable of generating code to compute the area and volume of regions on a 3D face model, using multiple prompts. 15 ChatGPT has understanding for oculoplastic research and can conduct thorough literature reviews, proposing novel experiments, improving surgical results through personalized surgical planning and patient communication within this domain. 16 Highlighting the implications of ChatGPT in plastic surgery research, Najafali et al 21 reported its ability to perform PRISMA systematic review and metanalyses from its own dataset.…”

“…3,16 Additionally, one study discovered that while it can generate code for task execution, the results achieved using this generated code were incorrect when compared to other mesh (vertex and polygon) algorithm processing methods. 15…”

Reliability and Agreement of Free Web-Based 3D Software for Computing Facial Area and Volume Measurements

“…We have recently introduced area and volume measurement techniques for facial surgeries, aimed at augmenting surgeons' abilities to precisely analyze facial structures and plan surgeries. This novel addition to facial analysis is intended to significantly improve surgical outcomes and enhance the overall success of facial surgical procedures [12,13]. We have developed open-source algorithms to measure area and volume on a 3D facial model [13] and then utilized these algorithms to enhance the free web-based software called Face Analyzer [14] to help surgeons perform a more in-depth analysis of a patient's face [1].…”

“…This novel addition to facial analysis is intended to significantly improve surgical outcomes and enhance the overall success of facial surgical procedures [12,13]. We have developed open-source algorithms to measure area and volume on a 3D facial model [13] and then utilized these algorithms to enhance the free web-based software called Face Analyzer [14] to help surgeons perform a more in-depth analysis of a patient's face [1]. The Face Analyzer software, hosted at digitized-rhinoplasty.com, is now capable of measuring the area and volume of certain regions, such as the dorsal hump, nasal dorsum, root of the nose (Radix), and tip of the nose, and it is based on several previous works [10,12,13].…”