Tue, 09/24/2024 - 12:51
I used Edge on the Box(50X60X80) for observation.
First, use BRepBuilderAPI_Transform to translate the box, and then output the json data of the corresponding edges before and after the translation. Finally, use a special json reader to view the obtained json data.
It is found that when theCopyGeom parameter of BRepBuilderAPI_Transform is true, whether the box is imported from an external STEP file or directly generated by Occ modeling, the information of the translated edges becomes shorter. Specifically, the information on CurveRepresentation becomes less.
The number of json data rows of EDGE on the CAD digital model before translation is 164, and the number of json data rows of Edge on the occ model is 213. In both cases, the number of json data rows of EDGE after translation is 115.
Can you tell me the specific reason? thanks!
Tue, 09/24/2024 - 15:26
Hello,
The issue you're encountering seems to be related to the validity of the transformation and the resulting edge representation. When you transform an edge, particularly a seam edge, the parametric representation may no longer match the surface. This can cause discrepancies, especially in cases involving cylindrical, conical, or spherical surfaces, where the 2D (PCurve) representation is more critical.
Right now I can't say that it is a bug, needs more investigation.
Best regards,
Dmitrii
Wed, 09/25/2024 - 03:06
I don't think it's an issue in occt, I just don't fully understand that the box has only been translated, even if it's a copy of the original box, its information content shouldn't be reduced.