Guides That Answer the Actual Question
Written around the tools on this site and the problems that bring people to them: broken meshes, oversized scans, parts that won't print, formats that won't open. Each guide says what works, what doesn't, and why.
How to Repair an STL File — Check First, Then Fix
Why STL files fail to print, how to spot the eight common mesh defects, and how to repair them in the browser. With broken test files to try.
Read guide →3D & CADSTL Mesh Defects, Illustrated: What a Checker Actually Finds
Every common STL defect shown in a 3D viewer with its check report: non-manifold edges, holes, flipped normals, duplicate faces and debris shells.
Read guide →3D & CADSTL vs STEP: Mesh or CAD, and When to Use Each
STL vs STEP: understand the difference between mesh and BREP geometry formats, when to use each, and how to convert between them.
Read guide →3D & CADSTEP vs STL: What to Send a Machine Shop
Why a CNC shop asks for STEP and not STL, what happens when you send a mesh for a quote, and how to get a printable STL back to a usable STEP.
Read guide →3D PrintingConvert CAD for 3D Printing: STEP to Printable STL
Getting a CAD model out of SolidWorks, Fusion 360 or FreeCAD into a printable STL: why you go via STEP, and how deflection trades detail for size.
Read guide →3D & CADHow to Reduce STL File Size Without Wrecking the Model
Why STL files get huge and three ways to shrink them: mesh decimation, re-exporting from CAD, and compressed formats. How far you can push each.
Read guide →3D & CAD3D File Formats Explained — STL, STEP, OBJ, FBX, GLTF, 3MF
Complete guide to 3D file formats: STL, STEP, OBJ, FBX, GLTF, 3MF, PLY. Learn when to use each format and how to convert between them.
Read guide →Animation & MocapVideo to Motion Capture: How Markerless Mocap Works
Turning ordinary video into motion capture: how markerless tracking works, how to film for it, and how to retarget BVH in Blender, Unity or Unreal.
Read guide →GIS & MappingGIS File Formats: GeoJSON, KML, Shapefile, GPX
GeoJSON vs KML vs Shapefile vs GPX: what each stores, which software reads it, and the traps around attributes, coordinate order and styling.
Read guide →SubtitlesSubtitle Formats Explained — SRT vs WebVTT vs ASS
SRT vs WebVTT vs ASS: what each format supports, which players accept them, what survives conversion, and how to fix broken accented characters.
Read guide →MedicalDICOM Files: How to Open, View and Convert DCM
What DICOM files are, why the CD from your hospital will not open, what window and level mean, and how to convert DICOM to JPG, PNG or PDF safely.
Read guide →Animation & MocapVideo Mocap in Blender: Import and Retarget BVH
BVH motion capture in Blender: the import settings that matter, frame rate mismatches, cleaning jitter in the Graph Editor, and retargeting.
Read guide →Animation & MocapVideo Mocap in Unity and Unreal: BVH to Humanoid
Getting BVH motion capture into Unity or Unreal 5: the Blender FBX bridge, Humanoid setup, IK Retargeter, root motion, and export settings.
Read guide →3D PrintingHow Thick Should 3D Print Walls Be?
Minimum wall thickness for FDM, resin and SLS with a table of real values, how to measure the walls of an STL, and what to do when they are too thin.
Read guide →3D PrintingHow Much Does a 3D Print Cost? The Real Math
Working out 3D printing cost from an STL: the material maths with an example, filament prices, and why service quotes run 3 to 10 times material.
Read guide →3D PrintingPrint Orientation: The Free Lever Most People Skip
How orientation changes supports, strength, finish and print time. The 45-degree rule, layer-line anisotropy, and finding the best angle for an STL.
Read guide →3D & CADHow to Convert STL to STEP (and When It Won't Work)
What an STL to STEP conversion really recovers, which parts convert well, which stay faceted, and why you repair the mesh before you start.
Read guide →3D & CADHow to Check if an STL Is Watertight
What watertight really means for an STL, three ways to check it, how to read a mesh report, and why watertight on its own is not enough to print.
Read guide →3D PrintingTurning a 3D Scan into a Printable or Editable Model
From raw 3D scan to usable model: repair holes and debris, decimate the mesh, then print or attempt CAD conversion. What works and what fails.
Read guide →3D & CADOBJ vs STL: What You Lose Converting Between Them
The real difference between OBJ and STL: colour, textures and UVs versus plain geometry. When each is right, and what conversion silently drops.
Read guide →3D PrintingWhat STL Export Tolerance Should I Use?
How the deflection setting controls STL quality and file size, with values for printing, machining and visualisation, and the mistake at each extreme.
Read guide →3D PrintingFixing "Non-Manifold" Errors from Your Slicer
What Cura, PrusaSlicer and Bambu Studio mean by non-manifold, whether you can ignore it, and the two-minute fix from error message to watertight.
Read guide →SubtitlesHow to Fix Out-of-Sync Subtitles (SRT & VTT)
Subtitles early or late? How to tell a constant offset from progressive drift, fix the offset in the browser, and why drift needs framerate retiming.
Read guide →MedicalHow to Convert DICOM to JPG (Without Ruining the Image)
Convert DICOM to JPG or PNG with the right window and level, so the image matches what the radiologist saw. Multi-frame files and privacy cautions.
Read guide →GIS & MappingHow to Convert a Shapefile to GeoJSON
Convert Esri Shapefiles to GeoJSON in the browser: which sidecar files you need, how reprojection to WGS84 works, and the attribute quirks both ways.
Read guide →3D Printing3MF vs STL: Should You Switch for 3D Printing?
What 3MF fixes about STL: units, compression, colours and print settings. What keeps STL alive, and how to convert between them in the browser.
Read guide →3D PrintingWhat Is a 3MF File? The Format Explained
A .3mf file is a zip-compressed 3D print format storing units, colours and several objects. What the 3MF file type holds, what opens it, and when to convert.
Read guide →3D & CADPreparing an STL for CNC Machining
You have an STL and the shop wants a real model: what a machinist can do with a mesh, the repair-then-convert path to STEP, and the dimension check.
Read guide →3D & CADGetting a Truly Editable STEP File from an STL
Why most STL to STEP conversions give you a faceted solid, when a converter can rebuild real planes and cylinders, and how to tell which you got.
Read guide →ImagesPassport Photo Requirements: Size, Background, Rules
The passport photo rules that actually cause rejections: size and head height, background, expression, glasses and lighting, and how to meet each.
Read guide →ImagesHow to Take a Passport Photo at Home
Taking a passport photo at home with a phone: the setup that removes shadows, how to frame and shoot, and cropping to the size your country wants.
Read guide →ImagesPassport and Visa Photo Sizes by Country
Passport photo sizes and head heights for the US, EU, UK, India, China and Canada in mm and inches, plus the two standards everything else follows.
Read guide →ImagesHow to Take a Baby or Infant Passport Photo
How to photograph a baby who cannot sit up or follow instructions: the white-sheet method, which rules relax for infants, and how to crop to size.
Read guide →3D & CADWhat Is a STEP File, and How to Open One
A .step file is CAD geometry, not a mesh. What the STEP file format stores, how to open a STEP file free, and what to do if you only need to 3D print it.
Read guide →3D & CADSTL to STEP in FreeCAD (or Skip the Setup)
The FreeCAD route from STL mesh to STEP file, step by step, what it actually produces, where it struggles, and how long it takes on real files.
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