Please support the thumbnails for Autodesk's Inventor & Fusion 360 IPT files

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Please support the thumbnails for Autodesk's Inventor & Fusion 360 IPT files

Postby m.Th. » Sun Feb 04, 2018 10:30 am

Autodesk Inventor is *THE* 3D parametric modelling solution of the biggest company in the market (the venerable Autodesk) and Fusion 360 is the facto standard for 3D modelling in 3D printing industry. Both have the same format for their 3D models (called parts), format which have IPT extension.

IPT files are in fact OLECF files with a thumbnail embedded in them in PNG format (since Inventor 2011).

How to extract the thumbnail: (take it for granted, don't ask me why - but frightening docs are available per request)

Use the Office Open XML engine to unzip the file (OLECF is a zip file) and search for the file... (wait for it) ... [5]Zrxrt4arFafyu34gYa3l3ohgHg . Yes, this name with NO extension. Open the file (is very small) and search for the following signature bytes (in Hex): "89 50 4E 47 0D 0A". Cut everything before and keep anything after "89 50 4E...", including these bytes.

You have now the PNG which represent the thumb of the file.

The obligatory sample is here:

Test Inventor - Fusion 360
(261.55 KiB) Downloaded 9 times

Feel free to contact me if any problems arise.

PS: You can do the above actions manually to see it for yourself using a Zip manager, a Hex editor (to find the signature & cut the "unnecessary" bytes from the beginning of the file) and a PNG viewer.
m. Th.

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