The paper introduces DAMMIF, an advanced implementation of the ab-initio shape-determination program DAMMIN for small-angle scattering (SAS) data. DAMMIF has been fully rewritten and optimized for speed, achieving 25-40 times faster execution compared to DAMMIN on a single CPU. The program now supports multiple CPUs and includes options for symmetry and anisometry constraints. The key improvements include an unlimited and growing search volume, which avoids artifacts caused by finite search volumes, and a bead-selection algorithm that ensures all beads representing the particle are interconnected. The paper also discusses the parallelization of the algorithm using OpenMP and provides a detailed comparison of the quality of reconstruction between DAMMIF and DAMMIN. DAMMIF is available in binary form for major platforms and is designed to enhance the efficiency and reliability of SAS data analysis.The paper introduces DAMMIF, an advanced implementation of the ab-initio shape-determination program DAMMIN for small-angle scattering (SAS) data. DAMMIF has been fully rewritten and optimized for speed, achieving 25-40 times faster execution compared to DAMMIN on a single CPU. The program now supports multiple CPUs and includes options for symmetry and anisometry constraints. The key improvements include an unlimited and growing search volume, which avoids artifacts caused by finite search volumes, and a bead-selection algorithm that ensures all beads representing the particle are interconnected. The paper also discusses the parallelization of the algorithm using OpenMP and provides a detailed comparison of the quality of reconstruction between DAMMIF and DAMMIN. DAMMIF is available in binary form for major platforms and is designed to enhance the efficiency and reliability of SAS data analysis.