1OGR DXF driver: Known issues 2============================ 3 4This is a brief list of known issues (mainly missing features) in the DXF 5driver. Anyone is welcome to contribute code that addresses these issues. 6 7## Reader 8 9* The following DXF entities are not supported at all: MESH, MPOLYGON, RAY, 10TABLE, TOLERANCE, WIPEOUT, XLINE. 11 12### 3DFACE 13 14* There seems to be some ambivalence as to whether 3DFACE entities should be 15represented as outlined polygons, as we currently do, or filled polygons. Any 16input on this issue would be appreciated. 17 18### DIMENSION 19 20* 3D (z-coordinate) and OCS (extrusion) support is absent from both the 21anonymous block logic and the fallback renderer. 22 23* The DIMENSION fallback renderer, used when the anonymous block is absent, is 24pretty rudimentary. I personally don't plan to work on it any further. Note 25that AutoCAD refuses to open DXF files that have a DIMENSION with no anonymous 26block. 27 28### HATCH 29 30* Fill types are not read. Any implementation of fill types (i.e. patterns) 31would need to be somewhat heuristic, given the basic set of choices available 32in the OGR style string spec. 33 34### LEADER 35 36* 3D (z-coordinate) and OCS (extrusion) support is absent. 37 38### LWPOLYLINE 39 40* Width support has not been added. 41 42### MLINE 43 44* Support for MLINESTYLE is missing. This means that only the basic geometries 45of MLINE entities are translated, not the more complex styling properties, 46such as different colors or linetypes for the different elements of the line. 47 48### MULTILEADER 49 50* 3D (z-coordinate) and OCS (extrusion) support is missing. This entity is 51very complex and adding 3D/OCS support would take a long time. 52 53### Text entities 54 55* Text using AutoCAD-specific SHX (plotter) fonts, such as "txt", is 56reported as being in Arial. 57 58* Text with a nonzero oblique angle, or that is upside down and/or backwards, 59will appear normal, due to the lack of support for these properties in an OGR 60style string. I don't think there is too much point adding these to the style 61string spec, as these attributes are little-used and not commonly available in 62other software. 63 64## Writer 65 66* The writer doesn't know about transparency. This means that hidden objects, 67which are represented using fully transparent colors by the reader, do not 68round-trip correctly. 69 70* As noted above, 3DFACE entities are represented by POLYGON geometries with a 71PEN() style tool, a combination which the writer handles poorly. 72 73* The writer does not write out ATTRIB entities for a POINT feature with a 74non-empty BlockAttributes field, that is to say, block attributes are not 75round-tripped. This is certainly a gap in the feature set, but I only plan to 76write this code if someone expresses a need for it. 77 78--- 79 80Alan Thomas, ThinkSpatial 81athomas@thinkspatial.com.au 82June 2018 83