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STL Directory Tree

As STL file format is designed to store a single triangulated mesh, DG Kernel Enterprise offers a way to store structured models in a file directory, called STL Directory Tree (STL Tree). The directory has specific structure described below.

See also DataFlow sample.

In this release any STL tree contains only .stl files and folders. The directory structure is designed to preserve structure of the mode with respect its child/parent relationship.


Above is an STL tree created for a model called "MyModel". 

There are two types of folders inside an STL Tree: Children folder and Object folder. 

Object folder can contain only a single (or none) stl file, which keeps geometry of a single object. and a single (or none) folder named "Children". Name of the stl file in an object folder must coincide with the name of the object folder.  Rectangle, Box and Triangle are the object folders in the above example. Rectangle folder contains a single file named Rectangle.stl.

A Children folder contains any (or none) number of stl files with arbitrary names and any number (or none) of Object folders. Children folders should not be empty. Top level folder or folder of the model ("MyModel" in the above example) is a Children folder.

Assuming that top level folder is at the level 0 all children folders are located at even levels in the tree. All Object folders are at odd levels.

During saving or loading of a DG Kernel model to/from an STL Tree objects are saved/loaded in separate stl files with the same name as the object.

Persistence to an STL tree can be performed with the help of IModelEx interface, which can be queried via: GetModel method of the DG Kernel component -> IModel_DG ->IModelEx. Methods IModelEx.SaveEx and IModelEx.LoadEx take a path of the top-level folder (Path of MyModel in example above) and reference to an ISTLDataContext_DG interface. The later interface is queried from the same IModelEx.  Methods of ISTLDataContext_DG allow setting various options for the import/export operations. See main documentation for details. Call ISTLDataContext_DG SetSeparateObjects(true) prior the save/ load operation will cause persistence to an STL tree as opposite to persistance to asingle STL file

Note that any model can be saved as single stl file if one does not set the SeparateObjects above or uses  ModelEx.Save, IModelEx.Load or simple by setting ModelPath property of the component. In this case whole model is considered as a single triangulated object. During every load of a single STL file the software detects if there are separate linked triangulated components inside the stl file, although it is not strictly conforms the STL standard. If such components are detected, they will be loaded as separate top-level objects in the model.