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Mesh displayed in 3D Viewer may come from different sources - imported from external file (glTF, JT, STL, PLY, OBJ), computed for analytical BRep geometry by BRepMesh (part of OCCT) and ExpressMesh (OCC component) algorithms or generated directly by application code.

The mesh is usually displayed shaded, but such a presentation is not suitable for analysis of mesh structure. In many cases, application developer needs other mesh presentations to locate issues (too many details, not enough details, local deviations, etc.) and make corrections based on analysis results (adjust mesh generation or export parameters).

In this case, mesh edges presentation becomes very helpful.

Draw Harness test case for Mesh Edges (Geometry Shader).

We are glad to inform the community of Open CASCADE Technology about a complete overhaul of BRepMesh component that is waiting for release in the upcoming 7.4.0 version. This overhaul, constrained by the requirement to keep non-regression of test cases collected during the last 20 years, took a while. In the end, the entire component has gained a new appearance. The new architecture simplifies the process of mesh generation over OCCT's BRep models and enables processing of some corner cases that were hard to handle before.

Hello,

We are pleased to inform you that the next release of OCCT, 7.3.0, is ready for beta testing, and invite you to test this beta version in your applications.

Use the commit tagged "V7_3_0_beta" in the Git repository for this testing. Alternatively, you can use either complete source archive or Windows installer including ready-to-use binaries built with VS 2010.

The next release of Open CASCADE Technology (7.3.0) will include the new algorithm intended for removal of the selected features from the model. The features that can be removed include holes, protrusions, gaps, chamfers, fillets etc. The defeaturing algorithm can be very useful in different contexts:

• Model simplification for numeric analysis, display on mobile devices, etc;
• In the direct modeling concept where the history of operations is unavailable;
• Removal of the proprietary details of the model before sharing it with others;
• Fixing the certain defects in the model, e.g. filling the gaps, holes etc.

Historically, OCCT 3D Viewer provided two options for dumping view content:

• V3d_View::ToPixMap() saving an image screenshot (bitmap) into formats like PNG, BMP, JPG.
• V3d_View::Export() exporting into vector graphics image format into formats like SVG, PDF, PS.

The latter one was provided with help of an external library gl2ps basing on OpenGL transformations feedback functionality (when OpenGL commands issued for rendering are captured and stored into dedicated buffer).

Development branch of Open CASCADE Technology (will be available in OCCT 7.3.0) introduces a new small feature for analyzing rendering performance issues #0029346.

Graphic3d_RenderingParams structure has been extended with a set of new properties for collecting and displaying performance counters in 3D Viewer.

Local Context was an essential part of OCCT 3D Viewer (AIS_InteractiveContext) for a long time. The concept of Local Context is quite simple and powerful - differentiation of two Viewer states: Neutral Point where all model objects reside, and Local Context augmenting main model presentations with auxiliary ones, created temporarily for particular task in user interaction. Even more, OCCT allows creation of multiple Local Contexts, defining some sort of stack of contexts.

Open CASCADE Technology 7.2.0 introduces a new feature in OCCT 3D Viewer for handling translucent presentations Weighted Blended Order-Independent Transparency (OIT), #0027925.

For many algorithms and tools to be usable in real applications, it is essential that these algorithms provide detailed information on the encountered problematic situations. In case of error, such details can be critically important for the user to be able to recognize the reason of the problem, and then either eliminate or bypass it.

The version 7.0 of Open CASCADE Technology features the new General Fuse (GF) based algorithm - Cells Builder. The algorithm can be very useful if you have to perform several standard Boolean operations such as CUT, COMMON and FUSE on the same shapes to obtain the final result.

Due to the possibility to get any split parts of the arguments (parts of the input shapes split in the places of intersection with other input shapes), which are called Cells (that’s where the name for the algorithm comes from), the Cells Builder may significantly simplify and speed up these operations as all intersections will be performed in a single run. In effect, the Cells Builder allows executing the Boolean expressions on the shapes, i.e. performing a sequence of standard Boolean operations in one operation.

The first version of the algorithm (available since OCCT 7.0) had limited capabilities. It worked only with the shapes of the same dimension - only VERTICES, or only EDGES, etc. Recently, the algorithm has been extended to also work with multi-dimensional input shapes. The next version of Open CASCADE (7.2) will feature this extension.