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 diagnose the eight common mesh defects, and how to repair them in the browser. Includes broken test files you can download and repair tools compared honestly.
Read guide →3D & CADSTL Mesh Defects, Illustrated: What a Checker Actually Finds
Every common STL defect shown in a 3D viewer with its real check report: non-manifold edges, holes, flipped normals, duplicate faces, debris shells, open surfaces, and hairline cracks.
Read guide →3D & CADSTL vs STEP — Complete Format Comparison for 3D Printing and CAD
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 for Manufacturing — What to Send a Machine Shop and Why
Why a CNC shop asks for STEP and not STL, what actually happens when you send a mesh for a quote, how tolerances and GD&T survive each format, and how to get a printable STL back to a manufacturable STEP.
Read guide →3D PrintingHow to Convert CAD for 3D Printing — From STEP to a Clean Printable STL
How to get a CAD model out of SolidWorks, Fusion 360, or FreeCAD and into a printable STL: why you convert through STEP, how the deflection setting trades smoothness against file size, and the pitfalls that ruin a print.
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 at a coarser resolution, and switching to a compressed format. How quadric decimation works, how far you can push it, and when each approach is right.
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 and How to Get Good Results
Turn ordinary video into motion capture data: how markerless mocap works, how to film for clean tracking, what BVH files contain, and how to retarget the result in Blender, Unity, and Unreal.
Read guide →GIS & MappingGIS File Formats Explained — GeoJSON, KML, Shapefile, and GPX Compared
GeoJSON vs KML vs Shapefile vs GPX: what each GIS format stores, which software reads it, the conversion gotchas (attribute limits, coordinate order, styling loss), and when to use each.
Read guide →SubtitlesSubtitle Formats Explained — SRT vs WebVTT vs ASS
SRT vs WebVTT vs ASS: what each subtitle format supports, which players and platforms accept them, what survives conversion, and how to fix the encoding errors that break accented characters.
Read guide →MedicalDICOM Explained — How to Open, View, and Convert DCM Medical Images
What DICOM (.dcm) files are, why the CD from your hospital will not open, what window/level means, which free viewers work, and how to convert DICOM to JPG, PNG, or PDF safely.
Read guide →Animation & MocapUsing Video Mocap in Blender — Import, Clean Up, and Retarget BVH
Step-by-step workflow for BVH motion capture in Blender: import settings that actually matter, fixing frame rate mismatches, cleaning jitter in the Graph Editor, and retargeting onto your own rig.
Read guide →Animation & MocapUsing Video Mocap in Unity and Unreal — BVH to FBX to Humanoid Retargeting
Get BVH motion capture into Unity or Unreal Engine 5: the Blender FBX bridge, Humanoid avatar setup in Unity, IK Retargeter in UE5, root motion choices, and export settings that avoid common failures.
Read guide →3D PrintingHow Thick Should 3D Print Walls Be?
Minimum wall thickness for FDM, resin, and SLS printing, with a table of real values. How to measure the walls of an STL before printing, and what to do when they are too thin.
Read guide →3D PrintingHow Much Does a 3D Print Cost? The Real Math
How to calculate 3D printing cost from an STL: material math with a worked example, filament prices by material, why service quotes are 3 to 10 times material cost, and how to cut the number.
Read guide →3D PrintingPrint Orientation: The Free Lever Most People Skip
How print orientation changes support material, part strength, surface finish, and print time. The 45-degree rule, layer-line anisotropy, and how to find the best orientation for an STL automatically.
Read guide →3D & CADHow to Convert STL to STEP (and When It Won't Work)
Converting an STL mesh to a STEP solid: what the conversion actually does (and does not recover), which parts convert well, which stay faceted or uneditable, and the honest workflow including repair first.
Read guide →3D & CADHow to Check if an STL Is Watertight
What watertight actually means for an STL, three ways to check it (browser tool, Blender, your slicer), how to read the numbers in a mesh report, and why watertight alone is not enough.
Read guide →3D PrintingTurning a 3D Scan into a Printable or Editable Model
The pipeline from raw 3D scan to usable model: repair holes and debris, decimate the oversized mesh, then print it or attempt CAD conversion. What works, what fails, honest expectations at each step.
Read guide →3D & CADOBJ vs STL: What You Lose Converting Between Them
The real difference between OBJ and STL: color, textures, and UVs versus plain geometry. When each format is right, how to convert OBJ to STL, and what the conversion silently drops.
Read guide →3D PrintingWhat STL Export Tolerance Should I Use?
How the deflection/tolerance setting controls STL quality and file size, with recommended values for printing, machining reference, and visualization — and the two mistakes 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 the warning, and the two-minute fix — from error message to watertight mesh.
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 with a time shift in the browser, and why drift needs framerate retiming instead.
Read guide →MedicalHow to Convert DICOM to JPG (Without Ruining the Image)
Convert medical DICOM files to JPG or PNG with correct window/level so the image matches what the radiologist saw. Multi-frame files, privacy cautions, and what a JPG can no longer do.
Read guide →GIS & MappingHow to Convert a Shapefile to GeoJSON
Convert Esri Shapefiles to GeoJSON in the browser: which of the sidecar files you actually need, how reprojection to WGS84 works, and the attribute quirks in both directions.
Read guide →3D Printing3MF vs STL: Should You Switch for 3D Printing?
What 3MF fixes about STL — units, compression, colors, print settings — and what still keeps STL alive. When each format wins, and how to convert between them in the browser.
Read guide →3D & CADPreparing an STL for CNC Machining
You only have an STL and the shop wants a real model: what a machinist can and cannot do with a mesh, the repair-then-convert path to STEP, and the dimension check that keeps parts in spec.
Read guide →3D & CADGetting a Truly Editable STEP File from an STL
Why most STL to STEP conversions produce faceted, hard-to-edit solids, when a converter can rebuild real analytic planes and cylinders instead, and how to tell which result you got.
Read guide →ImagesPassport Photo Requirements: Size, Background, and the Rules That Cause Rejections
The passport photo rules that actually get photos rejected: exact size and head height, plain background, expression, glasses, and lighting. What each rule means and how to meet it.
Read guide →ImagesHow to Take a Passport Photo at Home
A step-by-step method for taking a passport photo at home with a phone: the setup that removes shadows, how to frame and shoot, cropping to the right size, and printing it correctly.
Read guide →ImagesPassport and Visa Photo Sizes by Country
Passport photo dimensions and head-height requirements for the US, EU, UK, India, China, Canada, and more, in mm and inches, with the two standards that everything else follows.
Read guide →ImagesHow to Take a Baby or Infant Passport Photo
How to take a passport photo of a baby who cannot sit up or follow instructions: the on-a-white-sheet method, which rules relax for infants, and how to crop it to size.
Read guide →3D & CADSTL to STEP in FreeCAD (or Skip the Setup)
The FreeCAD method for converting an STL mesh to a STEP file, step by step: create shape from mesh, sew, convert to solid, refine, export. What you get, where it struggles, and a faster route.
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