Re:Rhino3d and DELFTShip

[Ian Scales]

Import to Rhino3D from DelftShip/FreeShip (DS/FS) is problematic. Presently, nothing works very well.

IGES works if the hull curvature is simple but if the hull has complex curves (as e.g. in historical ships), then IGES breaks the surface into a number of parts which when imported to Rhino cannot be fitted back together smoothly: the result is lumpy even after a rebuild. This is a pity, because with the exception of this really fatal problem, IGES delivers a surface that is easily editable in Rhino.

3D-DXF and OBJ export options both create a mesh. This is difficult to use in Rhino3D because most of Rhino’s commands deal with curves and surfaces. The mesh can be converted by Rhino into a NURBS polysurface, but this doesn’t help much, because it also has limited editability.

Moving on, STL produces a mesh with all faces divided diagonally, quite useless in Rhino. Lastly, Dxf polylines can be used to loft an editable new hull surface in Rhino, but it won’t be the same shape as the hull made in DS/FS: all your work of fairing in DS/FS is likely to be wasted.

The Rhino developers have made open source the library for reading and writing Rhino.3dm directly; this could freely be used in DelftShip if Martijn would decide to incorporate it. Until then, the relationship between Rhino3D and DelftShip is very crippled. This is a shame, because read/write in 3dm would make DelftShip very popular as a lower-cost and possibly more powerful alternative to the Orca3D plug-in for Rhino.