IfcGeomIterator: compute model's bounding box only if needed (IfcConvert --center-model used).

src/ifcconvert/IfcConvert.cpp

@@ -296,7 +296,7 @@ int main(int argc, char** argv)
 			"Applicable for DAE output.")
         ("center-model",
             "Centers the elements upon serialization by applying the center point of "
-            "all placements as an offset. Applicable for OBJ and DAE output.")
+            "all placements as an offset. Applicable for OBJ and DAE output. Can take several minutes on large models.")
         ("model-offset", po::value<std::string>(&offset_str),
             "Applies an arbitrary offset of form 'x;y;z' to all placements. Applicable for OBJ and DAE output.")
 		("site-local-placement",
@@ -638,7 +638,7 @@ int main(int argc, char** argv)
 
 	int old_progress = quiet ? 0 : -1;
 
-    if (center_model || model_offset) {
+    if (is_tesselated && (center_model || model_offset)) {
         double* offset = serializer->settings().offset;
         if (center_model) {
 			if (site_local_placement || building_local_placement) {
@@ -646,6 +646,11 @@ int main(int argc, char** argv)
 				delete serializer;
 				return EXIT_FAILURE;
 			}
+
+            if (!quiet) Logger::Status("Computing bounds...");
+            context_iterator.compute_bounds();
+            if (!quiet) Logger::Status("Done!");
+
             gp_XYZ center = (context_iterator.bounds_min() + context_iterator.bounds_max()) * 0.5;
             offset[0] = -center.X();
             offset[1] = -center.Y();

src/ifcgeom/IfcGeomIterator.h

@@ -285,6 +285,13 @@ namespace IfcGeom {
 			done = 0;
 			total = representations->size();
 
+			return true;
+		}
+
+        /// Computes model's bounding box (bounds_min and bounds_max).
+        /// @note Can take several minutes for large files.
+        void compute_bounds()
+        {
             for (int i = 1; i < 4; ++i) {
                 bounds_min_.SetCoord(i, std::numeric_limits<double>::infinity());
                 bounds_max_.SetCoord(i, -std::numeric_limits<double>::infinity());
@@ -319,8 +326,6 @@ namespace IfcGeom {
                     bounds_max_.SetZ(std::max(bounds_max_.Z(), pos.Z()));
                 }
             }
-
-			return true;
         }
 
 		int progress() const { return 100 * done / total; }