{
  "abstract": "Fiber diffraction is one of the few experimental techniques capable of resolving molecular structure in partially ordered, non-crystalline systems such as fibrous proteins, biopolymers and synthetic polymers. Because fiber diffraction patterns are complex, exhibiting paracrystalline order, packing defects and broad, overlapping reflections, their interpretation relies on model-based refinement, in which theoretical patterns simulated from candidate atomic models are iteratively compared with experiment. We present fdtbx, a modern, open and extensible Python toolbox for simulating X-ray fiber diffraction patterns directly from atomic coordinates. Built on the crystallographic library cctbx and designed for readability and multicore execution, fdtbx computes structure factors from a PDB model and constructs realistic reciprocal-space reflection profiles that incorporate the principal physical broadening mechanisms of fiber diffraction: finite crystallite size, orientational disorder (with Gaussian, Lorentzian and Voigt angular peak shapes) and paracrystalline (second-kind) lattice disorder in Hosemann's formulation. A per-reflection shell-quadrature scheme evaluates the required convolutions at arbitrary query points rather than on a fixed grid, giving direct control over the trade-off between accuracy and speed, and an analytic Ewald-projection routine maps each sampled reflection, with an appropriate Lorentz correction, onto a flat detector to produce a simulated pattern for direct comparison with measured images. We illustrate the toolbox on $α$-chitin, cellulose~I$α$ and I$β$, cellulose triacetate and A-form DNA, and outline a practical simulation workflow. By providing a transparent, well-documented and parallelizable implementation of the specialized algorithms of fiber diffraction, fdtbx lowers the barrier to reproducible model-based analysis.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.23245",
  "author_total": 1,
  "authors": [
    {
      "name": "Pawel Sikorski"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8ftzn0bwxxkv9.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.23245",
  "fulltext_url": null,
  "id": "8ftzn0bwxxkv9",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.23245",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ],
    [
      "openalex",
      "2505|Enzyme Structure and Function"
    ]
  ],
  "openalex": "W7204106929",
  "pdf_url": "https://arxiv.org/pdf/2608.23245",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-08",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8ftzn0bwxxkv9.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:54Z",
      "native_id": "2608.23245",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.23245"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "FDTBX - Computational Tools for Simulation of X-ray Fiber Diffraction Patterns from Atomic Coordinates",
  "title_text": "FDTBX - Computational Tools for Simulation of X-ray Fiber Diffraction Patterns from Atomic Coordinates",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:54Z",
  "url": "https://research.draconitic.com/paper/8ftzn0bwxxkv9",
  "venue": "arXiv",
  "versions": []
}