# DNA CAD / 3D-Printable Model Source Survey Date: 2026-05-08 Purpose: identify downloadable DNA structure models that can feed the CAD force probe work. This is a source survey, not an endorsement that any model is already mechanically valid for load testing. ## Best Candidates ### NIH 3D: DNA Segment Based on 1BNA Source: ```text https://3d.nih.gov/entries/251 https://3d.nih.gov/entries/download/251/2 ``` Why it matters: ```text PDB-based DNA segment based on 1BNA NIH 3D output includes STL / GLB / WRL / X3D / PNG good science-aligned starting point ``` Use: ```text baseline scientific DNA segment geometry extraction comparison against generated 1BNA pipeline ``` Hold: ```text likely fragile as a direct mechanical test object unless thickened or embedded ``` ### NIH 3D: Triplex and Duplex DNA Flexible Model Kits Source: ```text https://3d.nih.gov/entries/22792/1 https://3d.nih.gov/entries/download/22792/1 ``` Why it matters: ```text flexible kit based on 1BWG and 1BNA includes duplex and triplex components files include STL plus visualization formats explicitly designed as reconfigurable model parts ``` Use: ```text best candidate for force-probe style bench tests base-pair component load / snap-fit / connector behavior duplex versus triplex geometry comparison ``` Hold: ```text model page recommends sintered nylon for stacks FDM may need rescaling and connector tolerance checks ``` ### NIH 3D: DNA Playset Source: ```text https://3d.nih.gov/entries/259 ``` Why it matters: ```text 35,000,000:1 scale DNA playset four nucleotide parts snap together into arbitrary sequences mechanically inspectable modular model ``` Use: ```text sequence-dependent physical assembly tests connector tolerance / load distribution in modular DNA ``` Hold: ```text educational scale model, not atomistic force model ``` ### NIH 3D: Folding DNA Model Source: ```text https://3d.nih.gov/entries/3DPX-001475 ``` Why it matters: ```text modular DNA model that can be extended single strands can separate to illustrate base pairing includes detailed assembly and FDM printing notes ``` Use: ```text strong practical candidate for print-and-measure experiments base-pair snap fit strand separation repeat-unit load path testing ``` Hold: ```text pins may break if printed in weak orientation model may need scaling and print orientation controls ``` ### NIH 3D: Flexible ssDNA and ssRNA Source: ```text https://3d.nih.gov/entries/8880 ``` Why it matters: ```text teaching models of ssDNA / ssRNA in stick representation uses PDB 1EHZ successfully printed using laser sintering / elastomeric material per source ``` Use: ```text single-strand flexibility comparison material-dependent bend / torsion proxy ``` Hold: ```text not a double-helix lattice by itself ``` ## Secondary Candidates ### Sketchfab: DNA Stick and Ball Molecular Model Source: ```text https://sketchfab.com/3d-models/dna-stick-and-ball-molecular-model-a8d959ad7f6649a784ae9a874ade7826 ``` Why it matters: ```text downloadable 3D model built in ChimeraX from PDB ID 1BNA CC Attribution good visual / atomistic reference mesh ``` Use: ```text visual comparison atomistic 1BNA reference mesh inspection ``` Hold: ```text NoAI restriction noted by source high triangle count may require repair / thickening for actual printing ``` ### CGTrader: DNA Double Helix Free 3D Print Model Source: ```text https://www.cgtrader.com/free-3d-print-models/miniatures/other/dna-double-helix ``` Why it matters: ```text free model STL and Rhino 3DM formats marked prepared for 3D printing ``` Use: ```text decorative / gross double-helix geometry possible CAD-editable Rhino route ``` Hold: ```text not necessarily PDB-derived license and no-AI terms need review before derivative use ``` ### 3DCADBrowser: B-DNA Source: ```text https://www.3dcadbrowser.com/3d-model/b-dna ``` Why it matters: ```text B-DNA model formats include STL, OBJ, FBX, BLEND, DXF, DWG, and others atom spheres identify oxygen, nitrogen, hydrogen, carbon, phosphorus ``` Use: ```text format diversity CAD import / conversion experiments ``` Hold: ```text download terms may require account or credits source has spelling/metadata roughness verify license before reuse ``` ### MakerWorld: DNA Double Helix Source: ```text https://makerworld.com/en/models/437066-dna-double-helix ``` Why it matters: ```text free STL/CAD model DNA model with support guidance ``` Use: ```text quick print sanity check decorative helix comparison ``` Hold: ```text CC BY-NC-SA license not scientific geometry ``` ### Printables DNA Tag Source: ```text https://www.printables.com/tag/dna ``` Why it matters: ```text aggregates many DNA tagged STL models includes folding DNA model kit, double helix models, lamps, manipulatives ``` Use: ```text candidate discovery practical FDM variants compare support-free versus supported helix forms ``` Hold: ```text tag page contains mixed decorative, educational, and unrelated models vet each license and geometry manually ``` ## Generation Route ### RCSB PDB / PDB-101 + NIH 3D Workflow Sources: ```text https://pdb101.rcsb.org/learn/3d-printing https://pdb101-west.rcsb.org/learn/3d-printing/pdb-structures-and-3d-printing https://3d.nih.gov/submit ``` Why it matters: ```text RCSB PDB provides scientific source structures PDB-101 documents 3D printing workflows NIH 3D can process PDB / CIF and mesh files NIH 3D can export customized GLB or STL ``` Recommended structure IDs: ```text 1BNA B-DNA dodecamer 1BWG triplex DNA component in NIH flexible kit 1EHZ ssDNA / ssRNA teaching model source 4UN4 Cas9 with target DNA, useful for protein-DNA complex context ``` Use: ```text generate our own controlled source mesh from PDB data hash PDB input hash STL / GLB output record conversion parameters feed into CAD force-probe receipt ``` ## Shortlist for the Force-Probe Path Best practical order: ```text 1. NIH 3D Folding DNA Model 2. NIH 3D Triplex and Duplex DNA Flexible Model Kits 3. NIH 3D DNA Playset 4. NIH 3D DNA Segment Based on 1BNA 5. Self-generated 1BNA model through NIH 3D or ChimeraX ``` Rationale: ```text modular and snap-fit models are better bench objects than fragile atomistic meshes scientific 1BNA models are better for geometry truth but may need thickening decorative helices are useful as print controls but weak as biological models ``` ## Failure Rules ```text decorative helix treated as scientific DNA geometry -> hold PDB-derived mesh treated as mechanically printable without repair -> hold license omitted from candidate selection -> invalid source record downloaded STL used without hash / provenance -> invalid receipt atomistic visual mesh used as load-bearing model without thickening -> unsafe / invalid ```