Fixed bug in IFC where SweptDiskSolid tessellation would fail for polylines with only 2 points.

Indeed, the EstimateSampleCount is not always accurate in this case, as the number of generated curvature pointer is greater by one. Moreover, it is redundant to call EstimateSampleCount, as the SampleDiscrete method will provide the (correct) number of points anyway. This commit fix the described bug, but also increase the efficiency of the ProcessSweptDiskSolid method, as EstimateSampleCount is only called once now, instead of two times.

code/IFCGeometry.cpp

@@ -330,7 +330,11 @@ void ProcessSweptDiskSolid(const IfcSweptDiskSolid solid, TempMesh& result, Conv
     const unsigned int cnt_segments = conv.settings.cylindricalTessellation;
     const IfcFloat deltaAngle = AI_MATH_TWO_PI/cnt_segments;
 
-    const size_t samples = curve->EstimateSampleCount(solid.StartParam,solid.EndParam);
+	TempMesh temp;
+	curve->SampleDiscrete(temp, solid.StartParam, solid.EndParam);
+	const std::vector<IfcVector3>& curve_points = temp.verts;
+
+    const size_t samples = curve_points.size();
 
     result.verts.reserve(cnt_segments * samples * 4);
     result.vertcnt.reserve((cnt_segments - 1) * samples);
@@ -338,10 +342,6 @@ void ProcessSweptDiskSolid(const IfcSweptDiskSolid solid, TempMesh& result, Conv
     std::vector<IfcVector3> points;
     points.reserve(cnt_segments * samples);
 
-    TempMesh temp;
-    curve->SampleDiscrete(temp,solid.StartParam,solid.EndParam);
-    const std::vector<IfcVector3>& curve_points = temp.verts;
-
     if(curve_points.empty()) {
         IFCImporter::LogWarn("curve evaluation yielded no points (IfcSweptDiskSolid)");
         return;