Fixes problem with IfcCurveSegment.Placement direction for parabolic …

…vertical curves
IfcOpenShell · May 2, 2024 · c93704f · c93704f
1 parent 7af9944
commit c93704f
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/src/examples/IfcAlignment.cpp b/src/examples/IfcAlignment.cpp
@@ -163,7 +163,7 @@ std::pair<typename Schema::IfcCurveSegment*, typename Schema::IfcAlignmentSegmen
 
     auto curve_segment = new Schema::IfcCurveSegment(
         Schema::IfcTransitionCode::IfcTransitionCode_CONTSAMEGRADIENT,
-        new Schema::IfcAxis2Placement2D(p, new Schema::IfcDirection(std::vector<double>{1.0, 0.0})),
+        new Schema::IfcAxis2Placement2D(p, new Schema::IfcDirection(std::vector<double>{sqrt(1 - start_slope * start_slope), start_slope})),
         new Schema::IfcLengthMeasure(0.0),
         new Schema::IfcLengthMeasure(length),
         parent_curve);

diff --git a/src/ifcparse/IfcAlignmentHelper.cpp b/src/ifcparse/IfcAlignmentHelper.cpp
@@ -708,7 +708,7 @@ std::pair<Ifc4x3_add2::IfcCurveSegment*, Ifc4x3_add2::IfcCurveSegment*> mapAlign
 
         auto curve_segment = new Ifc4x3_add2::IfcCurveSegment(
             Ifc4x3_add2::IfcTransitionCode::IfcTransitionCode_CONTSAMEGRADIENT,
-            new Ifc4x3_add2::IfcAxis2Placement2D(new Ifc4x3_add2::IfcCartesianPoint({start_distance_along,start_height}), new Ifc4x3_add2::IfcDirection({1.0, 0.0})),
+            new Ifc4x3_add2::IfcAxis2Placement2D(new Ifc4x3_add2::IfcCartesianPoint({start_distance_along, start_height}), new Ifc4x3_add2::IfcDirection({sqrt(1.0 - start_gradient * start_gradient), start_gradient})),
             new Ifc4x3_add2::IfcLengthMeasure(0.0),
             new Ifc4x3_add2::IfcLengthMeasure(horizontal_length),
             parent_curve);