Check a SketchUp file: which version saved it, which SketchUp opens it
Drop a .skp model (or a .skb backup) and get the answer before you install anything: the SketchUp version that saved it, the plain “SketchUp 20XX or newer opens it; older ones refuse”, the preview picture SketchUp stored inside, saved as PNG, and the file size. Useful when SketchUp says “This model was created with a newer version of SketchUp”, or when someone sends you a file and you want to see what it is first.
The file is read by this tab on your device and is not uploaded, so a client’s house or an unreleased product goes nowhere.
What it shows
- The SketchUp version that saved it. A .skp starts with the words
SketchUp Modelstored in UTF-16, then a version string in braces:{16.1.1449}means SketchUp 2016, build 1449;{8.0.3117}means Google SketchUp 8. From 2013 on, the first number is the year less 2000. A model saved with File › Save As an older version carries that older number, which is what matters for opening it. - Which SketchUp opens it. Up to SketchUp 2020, a release that changed the format could not open files from newer releases, so a 2019 file needs SketchUp 2019 or newer. SketchUp 2021 introduced a format that every later release shares, so any file from 2021, 2024 or 2026 opens in SketchUp 2021 or newer, and SketchUp 2020 and older refuse all of them.
- The preview picture, as a PNG. SketchUp stores a picture of the view at the last save, 256 × 256 pixels in the SketchUp 2016 files tested here, 128 × 69 in a SketchUp 8 one. It is the first object after the file’s class list, a complete PNG. The page finds it by its PNG signature, checks every chunk’s checksum and its length against the length SketchUp wrote in front of it, shows it, and saves it byte for byte.
- The file size, and classification schemas. SketchUp 2014 and later append a small ZIP to the file listing the classification systems loaded in the model, such as IFC 2x3 in SketchUp Pro’s templates, used to tag objects as walls, slabs or doors for BIM export. The page names them from that ZIP’s
document.xml.
What it cannot do
- It cannot show the 3D model. The .skp format is closed: Trimble, which owns SketchUp, publishes no specification, only a programming kit for its own platforms. This page does not draw or measure faces, edges, groups or textures. To look at the model itself, use SketchUp for Web, SketchUp’s free web viewer and modeller (it needs a free Trimble account and uploads the file to Trimble’s cloud), or the free SketchUp Viewer app.
- It does not list components, materials, tags or scenes. Their names sit in the closed object stream after the preview. No published structure says where a name starts there, and picking out strings that look like names would mix real ones with fragments, so the page lists none rather than wrong ones.
- It does not convert or downgrade. There is no export to OBJ, STL or DAE and no Save As an older version. Someone with SketchUp can do both (File › Save As, choosing an older version in the list; File › Export › 3D Model), and the 3D model viewer here opens the exported OBJ, DAE or STL.
- The preview may be out of date. It is SketchUp’s own picture from the last save in SketchUp, not a render made here. A file changed afterwards by a plug-in or another program can carry an older picture, or none.
Useful to know about .skp files
- “This model was created with a newer version of SketchUp”
- Your SketchUp is older than the format of the file. Drop it here to see which version is needed. The sender can fix it without you upgrading: in desktop SketchUp, File › Save As, then choose an older version in the file-type list. Which older versions are offered depends on the sender’s release, so tell them the version this page shows for your copy of SketchUp.
- What .skb files are
- When SketchUp saves, it keeps the previous save beside the model as a backup:
.skbon Windows. It is a complete SketchUp file in the same format, so it opens here the same way, and renaming it to.skpopens it in SketchUp, which is the usual way to recover from a damaged or overwritten model. - Versions and their numbers
- The table this page uses, with its sources, is in skp-core.js: 3, 4 and 5 (SketchUp 3 to 5), 6 to 8 (Google SketchUp 6 to 8), then 13 to 26 for SketchUp 2013 to 2026 (2026 is build 26.0.429 in Trimble’s release notes). Numbers 9 to 12 were never released. A higher number than 26 is named by the same year rule and marked as newer than the table.
- Why the file is only partly read
- Everything after the preview is SketchUp’s own object stream, written for its own reader. The two strings at the start, the class list, the preview and the appended ZIP are plain enough in real files saved by SketchUp 8 and 2016 to read without guessing, so this page reads those and stops.