File Format FCStd/id

The FreeCAD Standard file format (.FCStd) is FreeCAD's main file format. It is a compound format, supports compression and embedding of different kinds of data.

Internals of .FCStd files
FCStd is a standard zip file, containing one or more files in a specific Structure. As such, it is possible to unpack a FCStd file using a regular zip decompression tool, but care needs to be taken while packing the contents of a FCStd file. FreeCAD contains a "Project Utility" to re-pack FCStd files, it's use is described in below.

Document.xml
This is the main xml file describing all the objects inside a FreeCAD document, that is, only the geometric and parametric definition of the objects, not their visual representation. If FreeCAD is ran in console mode (without the GUI), only this xml document will be used.=

GuiDocument.xml
This is the GUI counterpart of the Document.xml file. For each object described in the Document.xml, there is one corresponding object in GuiDocument.xml, describing the visual representation of that object (color, linewidth, etc).

Thumbnails/thumbnail.png
This is a 128x128 pixels thumbnail image of the document, which is a screenshot of the 3D view at save time. Thumbnails are generated only if the corresponding option is enabled in the FreeCAD preferences.

Templates/*.svg
In the Templates folder are stored the template svg files used in Drawing pages.

*.brep
These are the .brep shapes of all objects that have a Part shape in the Document.xml. Each object, even if it is parametric, has its shape stored as an individual .brep file, so it can be accessed by components without the need to recalculate the shape.

Structure
Structure of a typical FCStd file:

Change the source of the file .FCStd
It is possible to change the source of a file .FCStd but the procedure is not without risk it is for this reason that we need to work on a copy.

After having made an copy of your project, follow these steps :

Create a new directory and place your copy in that directory (there may be many files in your FCStd).


 * Go in Menu > tools > Project utility... Project utility
 * Source : Give your copy to unpack path.
 * Destination : Give the path to the unzipped files.
 * Click
 * Go to your directory and open both files GuiDocument.xml andt Document.xml using Notepad++ (Windows) (Notepad++ to modify a word in all open documents).
 * GuiDocument.xml : contains all your project information to the interface, display in the Combo view, the configuration of FreeCAD . ..
 * Example with Text004


 * Document.xml : contains all information relating to the constituent objects your project.
 * Example with Text004


 * Information such as :


 * as well as other definitions containers file= relate has a file and if you change example "DiffuseColor" in  You must also change the name of the file for correspondence.
 * Once the Word change is identified, search (your Word) and Replace by (your new word) and click on and your change will be the same in both files GuiDocument.xml and Document.xml.
 * When changes are complete, return to the tool Menu > Tools > Project utility... Create project
 * Source : Give the path of the file that you just changed and that is to restore.
 * Destination : Give the path of the FCStd file to restore.
 * Click In the new window click on  (to avoid errors by rewriting the file) and you post. Click on  you can check the "Load project file after creation".
 * If you have checked "Load project file after creation" your project will load in FreeCAD.
 * PS : It is imperative that it have concordance GuiDocument.xml, Document.xml documents and files without which there will be errors in your .FCStd file. To do this should always work on a copy of your project.

Other
Here, a file Converter utility ImageConv.