Site local placement (#240)

* ifcgeom: Add placement_rel_to for convert()

Change geometry conversion in `convert()` for `ObjectPlacement` such
that we can stop the `PlacementRelTo()` recursion when we hit an
`ObjectPlacement` that places a certain type, e.g. a `IfcSite'.

Introduce a new IteratorSetting `SITE_LOCAL_PLACEMENT` which will be
exposed in `IfcConvert`.

* IfcConvert: Add --site-local-placement

Some IFC authoring tools may put the global origo at a large distance
away from the actual building geometry. Also, the global X- and Y-axes
may be at arbitrary angles with natural building axes. Using
--center-model or --model-offset may place the converted geometry closer
to origo, but will still use the global IFC definition of axis
directions. Also, in a scenario with multiple IFC files for one
construction site, using --center-model on each of them would not
generate consistent geometry across OBJ or DAE files.

Solve this by introducing --site-local-placement which will disregard
the ObjectPlacement at the IfcSite level.

src/ifcgeom/IfcGeom.h

@@ -99,6 +99,10 @@ private:
 	std::map<int, SurfaceStyle> style_cache;
 
 	const SurfaceStyle* internalize_surface_style(const std::pair<IfcSchema::IfcSurfaceStyle*, IfcSchema::IfcSurfaceStyleShading*>& shading_style);
+
+	 // For stopping PlacementRelTo recursion in convert(const IfcSchema::IfcObjectPlacement* l, gp_Trsf& trsf)
+	IfcSchema::Type::Enum placement_rel_to;
+
 public:
 	Kernel()
 		: deflection_tolerance(0.001)
@@ -109,6 +113,7 @@ public:
 		, ifc_planeangle_unit(-1.0)
 		, modelling_precision(0.00001)
 		, dimensionality(1.)
+		, placement_rel_to(IfcSchema::Type::UNDEFINED)
 	{}
 
 	Kernel(const Kernel& other) {
@@ -313,6 +318,8 @@ public:
 #endif
 	}
 
+	void set_conversion_placement_rel_to(IfcSchema::Type::Enum type);
+
 #include "IfcRegisterGeomHeader.h"
 
 };

src/ifcgeom/IfcGeomHelpers.cpp

@@ -357,6 +357,10 @@ bool IfcGeom::Kernel::convert(const IfcSchema::IfcAxis2Placement2D* l, gp_Trsf2d
 	return true;
 }
 
+void IfcGeom::Kernel::set_conversion_placement_rel_to(IfcSchema::Type::Enum type) {
+	placement_rel_to = type;
+}
+
 bool IfcGeom::Kernel::convert(const IfcSchema::IfcObjectPlacement* l, gp_Trsf& trsf) {
 	IN_CACHE(IfcObjectPlacement,l,gp_Trsf,trsf)
 	if ( ! l->is(IfcSchema::Type::IfcLocalPlacement) ) {
@@ -372,12 +376,20 @@ bool IfcGeom::Kernel::convert(const IfcSchema::IfcObjectPlacement* l, gp_Trsf& t
 			trsf.PreMultiply(trsf2);
 		}
 		if ( current->hasPlacementRelTo() ) {
-			IfcSchema::IfcObjectPlacement* relto = current->PlacementRelTo();
-			if ( relto->is(IfcSchema::Type::IfcLocalPlacement) )
+			IfcSchema::IfcObjectPlacement* parent = current->PlacementRelTo();
+			IfcSchema::IfcProduct::list::ptr parentPlaces = parent->PlacesObject();
+			bool parentPlacesType = false;
+			for ( IfcSchema::IfcProduct::list::it iter = parentPlaces->begin();
+				  iter != parentPlaces->end(); ++iter) {
+				if ( (*iter)->is(placement_rel_to) ) parentPlacesType = true;
+			}
+
+			if ( parentPlacesType ) break;
+			else if ( parent->is(IfcSchema::Type::IfcLocalPlacement) )
 				current = (IfcSchema::IfcLocalPlacement*)current->PlacementRelTo();
-			else break;			
+			else break;
 		} else break;
 	}
 	CACHE(IfcObjectPlacement,l,trsf)
 	return true;
-}
+}

src/ifcgeom/IfcGeomIterator.h

@@ -755,6 +755,9 @@ namespace IfcGeom {
             kernel.setValue(IfcGeom::Kernel::GV_MAX_FACES_TO_SEW, settings.get(IteratorSettings::SEW_SHELLS) ? 1000 : -1);
             kernel.setValue(IfcGeom::Kernel::GV_DIMENSIONALITY, (settings.get(IteratorSettings::INCLUDE_CURVES)
                 ? (settings.get(IteratorSettings::EXCLUDE_SOLIDS_AND_SURFACES) ? -1. : 0.) : +1.));
+			if (settings.get(IteratorSettings::SITE_LOCAL_PLACEMENT)) {
+				kernel.set_conversion_placement_rel_to(IfcSchema::Type::IfcSite);
+			}
 		}
 
 		bool owns_ifc_file;

src/ifcgeom/IfcGeomIteratorSettings.h

@@ -80,8 +80,10 @@ namespace IfcGeom
             APPLY_LAYERSETS = 1 << 13,
 			/// Search for a parent of type IfcBuildingStorey for each representation
 			SEARCH_FLOOR = 1 << 14,
+			///
+			SITE_LOCAL_PLACEMENT = 1 << 15,
             /// Number of different setting flags.
-            NUM_SETTINGS = 14
+            NUM_SETTINGS = 15
         };
         /// Used to store logical OR combination of setting flags.
         typedef unsigned SettingField;