How-To : Know if a model contains B-Rep or Tessellated bodies
CAD files embed two kind of data for the 3D bodies: B-Rep and Tessellation.
A B-Rep body is described by mathematical parameters and a topology. In order to display a B-Rep body, HOOPS Exchange evaluate the parameters and generate a tessellation. The B-Rep parameters are accessible in the PRC.
A Tessellated body, is simply a list of vertices organized in faces.
Depending on the format, the PRC you get from a HOOPS Exchange conversion may contains B-Rep, Tessellation or both.
The tessellation may be generated by HOOPS Exchange or extracted from the CAD data. https://forum.techsoft3d.com/t/faq-how-does-exchange-handle-tessellation-data-while-reading-a-cad-file/1498
Instructions
After the conversion of a model to PRC, you can identify which entities are B-Rep and which are tessellated bodies.
Traverse the tree to the Representation Item level
Check the Representation Item type
A3DRiPolyBrep: this is a tessellated body. In HOOPS Demo Viewer it is described as “Faceted solid”
A3DRiBrepModel: this is a B-Rep body, you can parse its parameters and explore its topology.
A3DRiSet: this a collection of A3DRiRepresentationItem. You need to check the type of the children of this entity.
To follow-up or participate in the discussion, see this article in our Community Forum : https://forum.techsoft3d.com/t/how-to-know-if-a-model-contains-b-rep-or-tessellated-bodies/1502