When exporting a solid cylinder from Rhino to DWG (Solid 2007) it arrives there as two circular caps and TWO HALF-CYLINDERS. The same occurs when exporting solids with circular holes.
Why is that? It makes it utterly difficult to export fabrication models and have a CAM-software identify drilling features. (Not that feature recognition would be a good way of creating cam-data, but it’s the state of the art, unfortunately…)
In the image below,
- the red cylinder was created as an extrusion in Rhino6
- the green cylinder was created as a brep in Rhino6
- the black cylinder was created as cylinder in ACAD2020
Both Rhino-cylinders were exported to DWG Solid 2007. The black cylinder was added in ACAD2020 (where the two others where already solids with two half-surfaces…). Then the DWG was re-imported into Rhino 6.