File Types Reference
Raster · Vector · CAD · 3D · GIS · Layout
Raster Images
pixel grid · fixed resolution · photos & renders| Format | Full Name | Use For | Key Facts |
|---|---|---|---|
| .jpg | JPEG | Photos, renders, textures | Lossy — every save discards data. Never re-save an edited JPEG. Excellent compression for photographic content; artifacts appear on line art and text. |
| .png | PNG | Diagrams, screenshots, transparency | Lossless — compresses without losing data. Supports alpha (transparent pixels). Larger than JPG for photos; correct choice for graphics, line art, logos. |
| .tif | TIFF | Print, archival, high-res output | Lossless. Standard for high-resolution print. Large files. Use for source images when quality must be preserved across edits. |
| .gif | GIF | Legacy animations (dated) | 8-bit color only (256 colors max). No longer recommended for web — an animated GIF is often 5–10× the size of an equivalent clip. Use a looping <video> with MP4 (or WebM) instead: smaller, full color, smoother. |
| .webp | WebP | Web images (photos + graphics) | Modern format — supports both lossy and lossless. Smaller file than JPG/PNG at equivalent quality. Universal browser support. |
| .avif | AVIF | Web images — best-in-class compression | Newest web format (from the AV1 video codec). Smallest file of all at equal quality — typically 30–50% under JPG, beats WebP too. Lossy or lossless, supports transparency. Used for this course site. Slower to encode; near-universal browser support now. |
DPI / Resolution: DPI (dots per inch) only matters for print. A screen has no fixed DPI — pixel count is all that matters. For print: 300 DPI at final output size means a 8″×10″ print needs 2400×3000 pixels. "Exporting at 72 DPI" doesn't degrade quality if the pixel count is unchanged.
Vector
mathematical paths · infinite scale · drawings & diagrams| Format | Full Name | Use For | Key Facts |
|---|---|---|---|
| .svg | SVG | Web graphics, diagrams, icons | XML text file — open, human-readable. Scales infinitely. Can be embedded directly in HTML. Editable in Illustrator and in a text editor. |
| .ai | Adobe Illustrator | Illustrator working file | Proprietary. Preserves layers, artboards, live effects, symbols. Not portable without Illustrator. Save as .pdf or .svg for handoff. |
| .eps | Encapsulated PostScript | Legacy vector exchange, print shops | Old interchange format. Still accepted by some print bureaus. Prefer .svg or .pdf for new work — EPS has no transparency support. |
| PDF — as vector document | Vector output, layout, sharing | Dual nature: a PDF can contain both vectors and embedded rasters. When exported from Illustrator or InDesign with live vector data, it scales cleanly. Use for sharing drawings that must stay crisp. |
CAD / Drafting
real-world units · layers · measured drawings| Format | Full Name | Use For | Key Facts |
|---|---|---|---|
| .dwg | DWG | AutoCAD native, site survey files | Binary format. Stores layers, dimensions, blocks, model/paper space. Versioned — a 2020 .dwg may not open in AutoCAD 2010. Save down (Save As → older version) for wide compatibility. This is what you get from a surveyor. |
| .dxf | Drawing Exchange Format | CAD interchange, cross-software handoff | Text-based. Opens in almost any CAD, vector, or GIS program. Loses some AutoCAD-specific data (live dimensions, some blocks). Use when the receiver doesn't have AutoCAD. |
3D Models
geometry · NURBS vs mesh · fabrication & rendering| Format | Full Name / App | Use For | Key Facts |
|---|---|---|---|
| .3dm | Rhino 3DM | Rhino working file | Native NURBS + mesh geometry. Preserves layers, materials, history. The format to work in — only export to others for delivery. |
| .gh.ghx | Grasshopper Definition | Parametric scripts (the recipe, not the model) | Stores logic, not geometry. A .gh is the node graph — the rules that generate form — and runs on top of an open Rhino file. .gh is binary; .ghx is the same as readable XML. Share both the .gh and the .3dm it drives; the .gh alone produces nothing. |
| .obj | Wavefront OBJ | 3D mesh exchange (renderers, Illustrator) | Universal mesh format. Text-based. Carries mesh only — no NURBS. Pairs with .mtl file for materials. Exporting Rhino → OBJ converts NURBS to mesh: an irreversible approximation. |
| .fbx | Filmbox (Autodesk) | Game engines, animation, SketchUp handoff | Carries mesh + materials + animation + hierarchy. Use for Unity, Unreal, or exchanging with SketchUp / 3ds Max. Autodesk proprietary. |
| .stl | Stereolithography | 3D printing / fabrication | Mesh only (triangulated surfaces). No color, materials, or hierarchy. The universal fabrication format. Geometry must be a closed solid — open surfaces won't print. |
| .skp | SketchUp | Massing models, quick architecture | Proprietary. Common in architecture offices for quick massing. Imports into Rhino with some data loss (mesh only, no NURBS). Avoid as a final deliverable if Rhino is the project standard. |
NURBS vs. Mesh: NURBS (Rhino's native) = mathematically smooth curves and surfaces, precise at any scale, infinitely editable. Mesh = polygon faces (triangles/quads), a fixed approximation of shape. Every export from Rhino to OBJ, STL, or FBX converts NURBS to mesh — the smooth surface becomes faceted polygons. This conversion is one-way.
GIS / Spatial
georeferenced · coordinate systems · terrain & base data| Format | Full Name | Use For | Key Facts |
|---|---|---|---|
| .shp | Shapefile | Vector GIS data (roads, parcels, boundaries) | Not one file — a bundle. A shapefile requires at minimum: .shp (geometry), .dbf (attributes), .shx (index), and .prj (projection). Moving only the .shp breaks it. Always zip the whole folder. |
| .tif(GeoTIFF) | GeoTIFF | Aerial imagery, satellite, raster analysis | A standard TIFF with embedded coordinate metadata — it knows exactly where it sits on Earth. Opens as a regular image in Photoshop; opens as a map layer in QGIS. Source of aerial basemaps. |
| .geojson | GeoJSON | Web mapping, lightweight vector data | JSON-based. Human-readable. One self-contained file (unlike Shapefile). Standard for Mapbox, Leaflet, and web projects. Easy to inspect and edit in a text editor. |
| .kml / .kmz | Keyhole Markup / Zipped | Google Earth export/import | XML-based (KML) or zipped (KMZ). Carries placemarks, paths, polygons, ground overlays. Opens in Google Earth, QGIS, and many GIS apps. Commonly used for site boundary exchange. |
| .gdb | Esri File Geodatabase | Whole GIS projects — many layers in one container | Not a file — a folder. A .gdb is a directory full of cryptic system files; never open or move the pieces individually. Holds many feature classes, rasters, and tables together with topology rules. Esri's modern replacement for the Shapefile — no 2GB / 10-char-field limits. Zip the whole .gdb folder to share. |
| .dem | Digital Elevation Model | Terrain data, slope analysis, Rhino import | A raster where each pixel value = an elevation. The raw source for terrain models. Import into Rhino using HeightField. Also arrives as a GeoTIFF with elevation values instead of colors. |
Shapefile bundle: .shp geometry · .dbf attribute table · .shx index · .prj projection · (.cpg charset, .qpj QGIS projection, .sbn/.sbx spatial index — optional but include them)
Layout / Documents
InDesign · PDF · final delivery| Format | Full Name / App | Use For | Key Facts |
|---|---|---|---|
| .indd | InDesign Document | Layout working file (portfolio, boards) | Proprietary. Stores linked assets by path — if you move the .indd without its linked images, links break. Never submit .indd. Export to PDF for delivery. Package (File → Package) to bundle all links before sharing. |
| .idml | InDesign Markup Language | InDesign backwards compatibility handoff | XML-based InDesign interchange. Opens in InDesign versions older than the file was saved in. Use when collaborating with someone on an older subscription. Some live effects may be flattened. |
| .pptx | PowerPoint (Open XML) | Slide decks, pin-up boards | Secretly a ZIP archive. A .pptx is a renamed .zip bundle of XML + your embedded media. Rename deck.pptx → deck.zip, unzip, and every image sits full-resolution inside /ppt/media/ — the fastest way to pull pictures back out of a slide. The same trick works on .docx and .xlsx. |
| PDF — as final output | Submission, print, sharing | The universal delivery format. Embeds all fonts and linked images. Flatten transparencies before sending to a print bureau. Name files clearly: lastname-projectname-YYYYMMDD.pdf, not "untitled-2.pdf". |
Animation / Video
motion · web loops · presentation media| Format | Full Name | Use For | Key Facts |
|---|---|---|---|
| .mp4 | MPEG-4 (H.264) | Web video, deck embeds, shared motion | The universal video format. Plays on every device and browser with no plugin. The right replacement for animated GIF — far smaller, full color, smooth. Embed in PPTX; loop in a web <video>. |
| .webm | WebM (VP9 / AV1) | Web video — open alternative | Open, royalty-free. Slightly smaller than MP4 at equal quality and supports a true transparent (alpha) channel, which MP4 can't. Pair as a fallback alongside MP4 in <video>. |
| .mov | QuickTime | Editing, screen recordings (Mac) | Apple's container — high quality, large files. Common straight out of QuickTime / Keynote / phones. Convert to .mp4 before putting it on the web or into a deck for someone else. |
| .gif | GIF — see Raster | Legacy loops only | Animated but obsolete for this purpose: 256 colors, no audio, 5–10× the size of equivalent MP4. Reach for MP4/WebM instead. |
Animation in presentations — PPT vs. PDF: A PPTX is the only one that truly animates — element animations, slide transitions, and embedded MP4 that plays inline. A PDF is static: its embedded-video feature only works in Adobe Acrobat (dead in browsers, Preview, and phones). The trap: build motion in a deck, export to PDF for submission, and it silently dies. If the deliverable must move, the deliverable is a video (MP4) — export the whole deck out — not a PDF. Present live in PPTX/Keynote; freeze to PDF only when motion doesn't matter.
Web Coding
structure · style · behavior — three files make a site| Format | Full Name | Use For | Key Facts |
|---|---|---|---|
| .html | HyperText Markup | Structure — the content & its skeleton | The page itself: headings, paragraphs, images, links. Plain text, opens in any browser or editor. index.html is the front door of every site. Structure only — no styling, no logic. |
| .css | Cascading Style Sheets | Style — color, type, layout, spacing | Controls how the HTML looks. One stylesheet can style a whole site, so a single edit restyles every page. Keeps appearance separate from content. |
| .js | JavaScript | Behavior — interaction & logic | Makes the page do things: toggles, sliders, maps, fetched data. Runs in the browser. Optional — a site with zero JS still works; add it only where interaction is needed. |
For a portfolio site, these three are enough. HTML (structure) + CSS (style) + JS (behavior) = a complete static site — plain files a browser opens directly, no server, no database, no build step. Host it free on GitHub Pages or Netlify by uploading the folder. You only need frameworks (React, etc.) once a site has accounts, live data, or hundreds of pages — almost never for design work.
Cross-Cutting Concepts
Lossy vs. Lossless
Lossy (JPEG, lossy WebP) discards data to shrink the file — quality degrades with each save. Lossless (PNG, TIFF, GIF) compresses without discarding — the original is always recoverable. Work in lossless formats; deliver in whatever the brief requires.
Raster vs. Vector
Raster = a grid of pixels at a fixed resolution. "Scaling up" interpolates between pixels and blurs. Vector = mathematical paths (lines, curves, fills) that render at any size without degradation. Rule: drawings and diagrams in vector; photos and renders in raster.
What "Export" Actually Does
Export is a conversion, not a copy. Rhino → OBJ converts NURBS to mesh. InDesign → PDF flattens layers and embeds fonts. DWG → DXF strips AutoCAD-specific data. Every format conversion involves some loss — know what you're giving up before you export.
Why Handoff Loses Data
Files carry more than geometry: layers, parametric links, editable text, live effects. A PDF is a static snapshot of a layout, not the layout itself. Send the working file (with all links packaged) to a collaborator; send the PDF to a client or printer. Name files for the receiver, not yourself.
Compression
Compression reduces file size. Lossless compression (ZIP, PNG, LZW-TIFF) reconstructs the original exactly. Lossy compression (JPEG, MP3) permanently discards data the algorithm judges unimportant. File size alone tells you nothing about whether a compression is lossy.
Fluency ≠ Literacy
You've double-clicked files since childhood — that's fluency. Literacy is knowing what the file is: how it stores data, what it can and can't carry, what happens when you convert it. The same gap applies to AI tools: using a chatbot isn't the same as understanding what it's doing.