DWG vs DXF — What's the Difference and When to Use Each Format

DWG and DXF come from the same software house and both describe 2D geometry, but they are not interchangeable. DWG is AutoCAD’s native binary storage format. DXF is a text-based exchange format designed so that non-Autodesk software can read AutoCAD data. That distinction has practical consequences for every engineer who exports flat patterns, sends files to fabricators, or receives drawings from a customer. What DWG Actually Is DWG was created by Mike Riddle in 1982, predating AutoCAD itself. Autodesk acquired the format when they acquired the early Interact CAD program. It is a binary file format — you cannot open it in a text editor and make sense of it. The internal structure has changed with every major AutoCAD release: ...

8 September 2026 · 9 min · CadShift

SOLIDWORKS 2026 Sheet Metal DXF Export: Bend Lines Missing — Bug and Workaround

SOLIDWORKS 2026 SP3.2 introduced a regression specific to the flat-pattern DXF export path: bend lines appear in the cleanup window preview, the Bend lines checkbox in the DXF/DWG Output PropertyManager is checked, yet the written DXF has no bend line entities whatsoever. The geometry exports fine. Layers are correct. But the press brake operators get a DXF with no fold marks. This is a distinct failure mode from the SP3 regression documented in the general bend lines troubleshooting guide. That post covers the mapping file regression (enable-flag rows silently cleared) and per-user registry mismatches. The SP3.2 bug is different: the mapping file is intact, the registry value is correct, the entity bitmask is correct — and the export still omits bend lines. ...

6 September 2026 · 8 min · CadShift

How to Import a DXF and Turn It Into a Sheet Metal Part in SOLIDWORKS

A DXF file represents geometry in 2D — lines, arcs, splines, and circles with no thickness, no material, and no bend information. SOLIDWORKS’s sheet metal system represents a 3D part with folded geometry derived from a flat pattern governed by a K-factor and material thickness. The import workflow is about bridging those two representations, and there are three different paths depending on what you start with. What You’re Actually Working With Before choosing an approach, establish what the DXF contains: ...

2 September 2026 · 9 min · CadShift

Splitting a Curved Sheet Metal Part in SOLIDWORKS — Preserving Flat Pattern After Split

A sheet metal enclosure for an elliptical staircase, a conical shroud split into two halves for shipping, a large cylindrical tank section cut into panels for laser cutting — these all share the same fabrication requirement: a curved sheet metal body that must be divided into manageable pieces, each with its own flattenable geometry and its own DXF. SOLIDWORKS’s Split feature appears to solve this. It doesn’t. Applied to a curved sheet metal body, Split divides the geometry but destroys the flat pattern capability on every resulting piece. This post explains why that happens and gives three approaches that actually preserve flattenability. ...

25 August 2026 · 8 min · CadShift

SolidWorks DXF File Size — Why Your Drawing Export Is 100x Larger Than the Flat Pattern

A r/SolidWorks thread from last week: user exports a sheet metal part to DXF, sends it to the laser shop, gets a call saying the file is corrupt. The file is 20MB for a bracket with three bends. The shop’s nesting software chokes loading it. The user is exporting from the drawing, not from the part. This is the most common DXF export mistake in SolidWorks, and it is invisible until something downstream breaks. ...

23 August 2026 · 7 min · CadShift

DXF File Naming for Laser Cutting Nesting Software — Automate Part Routing from SOLIDWORKS Custom Properties

Every nesting operator knows the moment: 200 DXF files land in an import folder named Part1.dxf, Part2.dxf, FlatPattern-3.dxf. The cut program runs. Parts come off the machine. Now someone has to match each blank to an installation slot by hand—measuring, comparing, labeling. This is a manual step that costs 30–90 minutes per nest cycle, scales with order volume, and doesn’t improve no matter how much you spend on nesting software. The root cause is a mismatch between what SOLIDWORKS produces by default and what ProNest, Lantek, and JETCAM expect in order to route parts back to their jobs automatically. ...

15 August 2026 · 8 min · CadShift

Working with Large STEP Files in SOLIDWORKS: Sheet Metal Rebuild and Flat-Pattern DXF Workflow

You receive a STEP file from a supplier or another team. It opens in SOLIDWORKS as an assembly with hundreds of sub-components. Some of them are clearly bent sheet metal parts—brackets, enclosure panels, mounting clips. Your goal is to get flat-pattern DXF files for the laser shop. When you right-click a component and look for Flat Pattern, it’s not there. SOLIDWORKS treats every STEP-imported body as a dumb solid: geometry only, no feature tree, no bend data, no flat pattern. Even if the body was originally modeled as sheet metal, none of that intelligence survives the STEP format. ...

11 August 2026 · 11 min · CadShift

Tube Laser vs Sheet Metal Laser — Which SolidWorks Workflow for Which Part

A r/SolidWorks thread from August 2026 captures the confusion exactly: an engineer is trying to export a flat pattern DXF from a SolidWorks weldment to send to a tube laser shop. Every suggestion in the thread involves model edits, workarounds, or converting the weldment to sheet metal. Nobody points out the real issue — they are trying to apply a sheet metal export workflow to a part that belongs in a completely different machine category. ...

8 August 2026 · 8 min · CadShift

SolidWorks DXF Export — Why Bend Lines Disappear and How to Get Them Back

If bend lines stopped appearing in your DXF exports after a SolidWorks service pack update, you are not alone. The r/SolidWorks threads from August 2026 show multiple engineers hitting this after 2025 SP5 and 2026 SP3. Some had working configurations for years. They installed the update, exported a flat pattern, and the bend lines were gone. The problem is fixable — but only if you understand that bend lines disappear for fundamentally different reasons depending on how you export. Applying the wrong fix wastes time and leaves you thinking the issue is deeper than it is. ...

7 August 2026 · 11 min · CadShift

FreeCAD PartDesign Tutorial — Body Container, Sketcher, and Exporting STEP, DXF & STL

FreeCAD’s PartDesign workbench is the closest equivalent to SolidWorks’ Part environment. It uses a feature-based, parametric modeling approach built on OpenCASCADE Technology (OCCT) — the same geometry kernel that powers CATIA and Salome. If you’re coming from SolidWorks, Inventor, or any history-based modeler, you’ll recognize the concepts but encounter a few structural differences that aren’t obvious from the UI. This guide covers what actually matters for getting productive: the Body container model, how the Sketcher’s constraint system differs from what you’re used to, the core PartDesign features and their underlying OCCT operations, the topological naming problem that plagued earlier versions (and the fix in FreeCAD 1.0), and how to export finished geometry to STEP, DXF, and STL using FreeCAD’s import/export pipeline. ...

30 July 2026 · 12 min · CadShift