View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0000339||FreeCAD||Feature||public||2011-04-14 06:17||2011-09-02 14:29|
|Priority||normal||Severity||minor||Reproducibility||have not tried|
|Target Version||Fixed in Version||0.12|
|Summary||0000339: Keep separable IGES geometry|
FreeCAD should keep separate geometry when importing from IGES when possible (IGES groups and subfigures ).
Discussion in https://sourceforge.net/apps/phpbb/free-cad/viewtopic.php?f=3&t=335&p=2147&hilit=igs#p2147 is misleading in claiming that all hierarchy is lost with IGES. OCC supports IGES groups and subfigures, so there is no reason for FreeCAD to throw them away.
I have verified this with manual import of IGES in pythonOCC, and CADExchanger (also OCC based) keeps groups without problem.
Although solids are indeed lost in IGES, groups of faces can still be useful for saving/exporting individually, etc.
Sometimes it is even possible to stitch them back up into shells and solids, but that's for another RFE.
|Tags||No tags attached.|
Actually, just noticed the "Convert to solid" option, and seems to work ok,
at least for a couple of parts i tried on that I exported from an IGES as
individual BReps using CADExchanger.
So it would be nice if FreeCAD kept the IGES groups, and this step could
then be skipped.
How does it work? For STEP we do it this way:
* go through all solids and add an own object to the document (of course
not possible with IGES)
* go through all shells which are not part of a solid...
* go through all faces which are not part of a shell
* go through all wires which are not part of a face
* go through all edges which are not part of a wire
* go through all vertexes which are not part of an edge
Does it work the same way with IGES? If not, would it be possible to share
your python code to achieve that?
But the first step is possible with some IGES models, there are solid
entities (see OCC iges.pdf). This is shown in pythonOCC's
result_export_multi.iges sample and my script of the same name.
In the more common case when solid entities are not used in the IGES
model, groups and subfigure entities can still be imported as separate
compounded shapes, as shown in the other script. Surely these can be used
as separate objects in FreeCAD? FreeCAD seems to use the other approach
where only one compounded shape is imported, and the separation is lost.
Very interesting. If someone has time...
I will concentrate on STEP for my self.
||Done in r4872|
|2011-04-14 06:17||wmayer||New Issue|
|2011-04-14 06:20||wmayer||Note Added: 0000786|
|2011-04-14 06:20||wmayer||Description Updated|
|2011-04-14 06:21||wmayer||File Added: test_multi_iges.zip|
||Note Added: 0000834|
||Status||new => acknowledged|
|2011-09-02 14:29||wmayer||Note Added: 0001033|
|2011-09-02 14:29||wmayer||Status||acknowledged => closed|
|2011-09-02 14:29||wmayer||Resolution||open => fixed|
|2011-09-02 14:29||wmayer||Fixed in Version||=> 0.12|