Question
When exporting a curved object assigned to an alignment in 3D dwg format, the curves are not reflected.
Answer
In the options for 3D dwg Export in CIM, there are options that determine the shape: Poly Face Mesh and BREP.
Poly Face Mesh is a setting that exports objects as polygons (mainly triangles) in the form of a Mesh. Poly Face Mesh can adjust precision through the Accuracy Angle option, where a lower value indicates higher precision.
Figure 1. Poly Face Mesh
BREP is a setting that exports objects as curves and surfaces. Therefore, BREP does not have an Accuracy Angle option.
When exporting objects as BREP in CIM, for some shapes that cannot be created as BREP, the program internally converts the shapes to Poly Face Mesh and exports them, and the following Warning Message is displayed.
Figure 2. Warning message when applying BREP
Additionally, the Accuracy Angle value at this time is the value applied in Poly Face Mesh. Therefore, to create an accurate object in cases where BREP is incomplete, the Accuracy Angle value should be reduced.
The following is a comparison of the results of the 3D dwg Export with Accuracy Angles of 15° and 5°, respectively.
| Accuracy Angle: 15° | Accuracy Angle: 5° |