In this study, we developed a new 3-dimensional (3D) preoperative planning software and investigated its effectiveness by measuring orbital volume change. Fifty-six patients who underwent unilateral orbital wall reconstruction between December 2015 and February 2018 in our institute were recruited. We developed an orbit-specific automatic 3D modeling software (Osteopore CMF 3D) that can automatically detect orbital fracture site, process mirroring, measure volume, and then produce a customized orbital implant. Using preoperative and postoperative 3D computed tomography, orbital volume was measured and compared between Osteopore CMF 3D and the widely used Mimics. Intraclass correlation coefficient between Osteopore CMF 3D and Mimics showed 90.6% concordance for preoperative injured site orbital volume and 86.7% concordance for postoperative orbital volume, both being statistically significant (preoperative intraclass correlation coefficient, 0.906 [confidence interval {CI}, 0.840-0.945; P < 0.000]; postoperative intraclass correlation coefficient, 0.867 [CI, 0.773-0.922; P < 0.000]). For uninjured sites, the 2 software packages showed 76.6% preoperative concordance and 83.9% postoperative concordance, both being statistically significant (preoperative intraclass correlation coefficient, 0.766 [CI, 0.600-0.863; P < 0.000]; postoperative intraclass correlation coefficient, 0.839 [CI, 0.725-0.905; P < 0.000]). This study introduces our newly developed 3D surgical planning software specialized for orbital wall reconstruction and demonstrates its performance to be comparable with that of a widely used software.