![]() Said differently, if you skip these files, you'll have to re-select all the functions operands to re-attach/design faces to recompute the object which is painful.Īs a side node, this is the main reason for breakage of your model when you update some value in the bottom of the function stack in FreeCAD, since the names are not "constant". However, they contains names for geometry features (edges, face, etc.) and when applying functions on your object, these names are what's used for referring the function's operands. This format is described in OpenCascade which is the geometry engine library used by FreeCAD to model objects.Īs far as I've tried, FreeCAD is able to regenerate these files as well by itself. So it's safe to skip them when generating your own file, FreeCAD will just use default value in that case.BRPīRP files contains the BREP format of OpenCascade (OCC) serialization of sketches. Then, you'll find N elements (in this case, RGB colors, stored as 32 bits, in format 0x00RRGGBB, with 8 bits per color component)įreeCAD does not need any of these files to open the document. The first 32 bits contains the element count of the array (in the example above, it's 1, stored in little endian). The files with the name containing ColorArray are probably used for presentation of the document in the GUI. Of all thoses files, only one is important for FreeCAD to bootstrap the document, it's Document.xml (see below). I'm documenting the file format from what I understood from it since I'm using it in my Parametizer tool FreeCAD file formatĪ FreeCAD file (with extension. You'll be able to open, modify and also generate a document since it's open. But since it's not happening, FreeCAD at least does not lock you in. ![]() Why using FreeCAD's format will be better ?Īctually, a true, industry wide standard would be better. Also, they enjoy vendor lock in as it improves their sales (if all you have is a solidworks file, you'll need Solidworks to open it). Proprietary software don't want to disclose the internal working of their geometry engine, or simply, don't want to maintain the functions implemented in a version in later versions. All CAD software have their own way to build objects (although it seems to converge to the same way of thinking). You will not design your object the same if the only tool you have is a mesh editor or a CSG (understand: boolean) engine. Why isn't any standard parametric CAD file format?Ī parametric file format is often linked with a way of thinking your object. ![]() It would also help democratize the file format. It's not efficient.Ī parametric CAD file format on the other side would let the customer modify some parameters on her own. It'll take double time to achieve this simple operation, the customer asking for a change, you doing the update in your software and sending the modified file back. If the customer wants to update one dimension, she'll have to ask you again to regenerate a STEP file with the updated length. You'll build an object with your customer's desired dimensions, and export a STEP file. So, let's say you want to give a model of a drawer to a customer. So, once you receive a STEP file, you can't modify the object (you can use functions on top, but none of the functions used to build the object is available or described). It describes the final surfaces of an object, but not how it's made. I won't describe what STEP is capable of, but I'll point what it's not: This post is based on FreeCAD 0.20 Why is it important ?įor inter exchange with other CAD software, the industry created the STEP file format. Beware however that the file format is not a standard, so it'll likely evolve with FreeCAD versions.
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