Don't trim loft at profiles by default

ChangeLog.md

@@ -1,6 +1,14 @@
 Changelog
 =========
 
+## [Unreleased]
+
+### Breaking Changes
+- `CTiglAbstractGeometricComponent::GetLoft()` now returns untrimmed loft by default. Use `GetTrimmedLoft()` for the previous behavior (with UV cutting at profile positions). This affects `CCPACSWing` and `CCPACSFuselage` (and their segments). [#1262](https://github.com/DLR-SC/tigl/issues/1262)
+
+### Features
+- Add optional UV profile cutting to `CTiglMakeLoft` via `setEnableProfileCutting(bool)`. When enabled, creates seams at each profile wire position for consistent UV parameterization. Wing and fuselage builders now build both trimmed and untrimmed lofts on demand. [#1262](https://github.com/DLR-SC/tigl/issues/1262)
+
 Changes since last release
 ----------------
 2025/09/26

TIGLCreator/src/TIGLCreatorContext.cpp

@@ -396,6 +396,7 @@ Handle(AIS_Shape) TIGLCreatorContext::displayShape(const TopoDS_Shape& loft, boo
     myContext->SetTransparency(shape, transparency, Standard_False);
     myContext->SetDisplayMode(shape, shaded, Standard_False);
     shape->SetOwnDeviationCoefficient(settings.tesselationAccuracy());
+    shape->SetOwnDeviationAngle(settings.tesselationDeviationAngle());
 
 #if OCC_VERSION_HEX >= VERSION_HEX_CODE(6,7,0)
     if (!myShader.IsNull()) {
@@ -433,6 +434,7 @@ Handle(AIS_Shape) TIGLCreatorContext::displayShape(const PNamedShape& pshape, bo
     myContext->SetTransparency(shape, transparency, Standard_False);
     myContext->SetDisplayMode(shape, shaded, Standard_False);
     shape->SetOwnDeviationCoefficient(settings.tesselationAccuracy());
+    shape->SetOwnDeviationAngle(settings.tesselationDeviationAngle());
 
 #if OCC_VERSION_HEX >= VERSION_HEX_CODE(6,7,0)
     if (!myShader.IsNull()) {
@@ -683,6 +685,7 @@ Handle(AIS_InteractiveObject) TIGLCreatorContext::displayShapeHLMode(const TopoD
     myContext->SetTransparency(shape, transparency, Standard_False);
     myContext->SetWidth(shape, 3, Standard_False);
     shape->SetOwnDeviationCoefficient(settings.tesselationAccuracy());
+    shape->SetOwnDeviationAngle(settings.tesselationDeviationAngle());
 
 #if OCC_VERSION_HEX >= VERSION_HEX_CODE(6, 7, 0)
     if (!myShader.IsNull()) {

TIGLCreator/src/TIGLCreatorDocument.cpp

@@ -1752,7 +1752,7 @@ void TIGLCreatorDocument::drawAllFuselagesAndWingsSurfacePoints()
     for (int fuselageIndex = 1; fuselageIndex <= GetConfiguration().GetFuselageCount(); fuselageIndex++) {
         auto& fuselage = GetConfiguration().GetFuselage(fuselageIndex);
 
-        app->getScene()->displayShape(fuselage.GetLoft(), true, getDefaultShapeColor());
+app->getScene()->displayShape(fuselage.GetLoft(), true, getDefaultShapeColor());
 
         for (int segmentIndex = 1; segmentIndex <= fuselage.GetSegmentCount(); segmentIndex++) {
             // Draw some points on the fuselage segment

TIGLCreator/src/TIGLCreatorSettings.cpp

@@ -21,12 +21,13 @@
 
 #include <iostream>
 #include <algorithm>
+#include <cmath>
 #include "TIGLCreatorMaterials.h"
 #include <QCoreApplication>
 #include <qglobal.h>
 #include "TIGLCreatorSettings.h"
 
-const double DEFAULT_TESSELATION_ACCURACY = 0.000316;
+const double DEFAULT_TESSELATION_ACCURACY = 0.004;
 const double DEFAULT_TRIANGULATION_ACCURACY = 0.00070;
 const QColor DEFAULT_BGCOLOR(169,237,255);
 const QColor DEFAULT_SHAPE_COLOR(0, 170 ,255, 255);
@@ -114,6 +115,23 @@ void TIGLCreatorSettings::setDefaultMaterial(const QString& material)
     _defaultMaterial = tiglMaterials::materialMap[material];
 }
 
+double TIGLCreatorSettings::tesselationDeviationAngle() const
+{
+    // Map current tesselation accuracy (linear) to an angular deviation using the same logarithmic mapping
+    // NOTE: intentionally decoupled from the dialog slider endpoints. The angle
+    // is a pure function of the accuracy value, so keeping these fixed means a
+    // given accuracy always yields the same angle regardless of slider remapping.
+    const double WORST_TESSELATION = 0.01;
+    const double BEST_TESSELATION  = 0.000002;
+    const double WORST_ANGLE = 0.15; // rad (~8.6°) coarse
+    const double BEST_ANGLE  = 0.012; // rad (~0.69°) fine
+    double t = std::log(WORST_TESSELATION / _tesselationAccuracy) /
+               std::log(WORST_TESSELATION / BEST_TESSELATION);
+    t = std::max(0.0, std::min(1.0, t));
+    // Interpolate angle in log-space
+    return WORST_ANGLE * std::pow(BEST_ANGLE / WORST_ANGLE, t);
+}
+
 double TIGLCreatorSettings::tesselationAccuracy() const
 {
     return _tesselationAccuracy;

TIGLCreator/src/TIGLCreatorSettings.h

@@ -47,6 +47,7 @@ class TIGLCreatorSettings : public QObject
     void setTriangulationAccuracy(double);
 
     double tesselationAccuracy() const;
+    double tesselationDeviationAngle() const;
     double triangulationAccuracy() const;
 
     void setBGColor(const QColor&);

TIGLCreator/src/TIGLCreatorSettingsDialog.cpp

@@ -33,8 +33,8 @@
 #include "TIGLCreatorSettingsDialog.h"
 
 
-#define WORST_TESSELATION 0.01
-#define BEST_TESSELATION 0.00001
+#define WORST_TESSELATION 0.05
+#define BEST_TESSELATION 0.0005
 
 #define WORST_TRIANGULATION 0.01
 #define BEST_TRIANGULATION 0.00005
@@ -157,7 +157,8 @@ void TIGLCreatorSettingsDialog::updateEntries()
     double mu = log(dmax/dmin)/double(imax-imin);
     double c  = dmax / exp(-mu * (double)imin);
 
-    int tessVal = int (log(c/_settings.tesselationAccuracy())/mu);
+    int tessVal = static_cast<int>(std::lround(log(c/_settings.tesselationAccuracy())/mu));
+    tessVal = std::clamp(tessVal, sliderTesselationAccuracy->minimum(), sliderTesselationAccuracy->maximum());
     sliderTesselationAccuracy->setValue(tessVal);
 
     dmax = WORST_TRIANGULATION, dmin = BEST_TRIANGULATION;
@@ -166,7 +167,8 @@ void TIGLCreatorSettingsDialog::updateEntries()
     mu = log(dmax/dmin)/double(imax-imin);
     c  = dmax / exp(-mu * (double)imin);
 
-    int triaVal = int (log(c/_settings.triangulationAccuracy())/mu);
+    int triaVal = static_cast<int>(std::lround(log(c/_settings.triangulationAccuracy())/mu));
+    triaVal = std::clamp(triaVal, sliderTriangulationAccuracy->minimum(), sliderTriangulationAccuracy->maximum());
     sliderTriangulationAccuracy->setValue(triaVal);
 
     _bgcolor = _settings.BGColor();

src/common/tiglcommonfunctions.cpp

@@ -185,6 +185,18 @@ unsigned int GetNumberOfFaces(const TopoDS_Shape& shape)
     return iFaces;
 }
 
+int FacesPerSegment(int nFaces, int nSegments)
+{
+    if (nSegments <= 0) {
+        return 1;
+    }
+    int facesPerSegment = (nFaces + nSegments - 1) / nSegments;
+    if (facesPerSegment < 1) {
+        facesPerSegment = 1;
+    }
+    return facesPerSegment;
+}
+
 unsigned int GetNumberOfSubshapes(const TopoDS_Shape &shape)
 {
     if (shape.ShapeType() == TopAbs_COMPOUND) {

src/common/tiglcommonfunctions.h

@@ -177,6 +177,11 @@ TIGL_EXPORT unsigned int GetNumberOfEdges(const TopoDS_Shape& shape);
 // returns the number of faces of the current shape
 TIGL_EXPORT unsigned int GetNumberOfFaces(const TopoDS_Shape& shape);
 
+// Distributes nFaces faces evenly over nSegments segments, rounding up so that
+// every face is covered (ceil division). The result is clamped to a minimum of 1.
+// Used to determine the number of loft faces per profile segment.
+TIGL_EXPORT int FacesPerSegment(int nFaces, int nSegments);
+
 TIGL_EXPORT TopoDS_Edge GetEdge(const TopoDS_Shape& shape, int iEdge);
 
 TIGL_EXPORT TopoDS_Face GetFace(const TopoDS_Shape& shape, int iFace);

src/control_devices/CCPACSControlSurfaceOuterShapeLeadingEdge.cpp

@@ -28,8 +28,6 @@
 #include "Debugging.h"
 
 #include <BRepOffsetAPI_ThruSections.hxx>
-#include <BRepAlgoAPI_Common.hxx>
-#include <BRepBuilderAPI_Transform.hxx>
 
 namespace tigl
 {
@@ -47,31 +45,7 @@ PNamedShape CCPACSControlSurfaceOuterShapeLeadingEdge::GetLoft(PNamedShape wingC
     assert(shapeBox);
 
     // perform the boolean intersection of the flap box with the wing
-
-    // Workaround for OpenCASCADE boolean intersection issues on LEDs:
-    // OCC seems to fail to create correct side faces when LEDs and the wing intersect
-    // along tangential or very thin regions (typical for LEDs).
-    // TED intersections seem to work fine.
-    // 
-    // Solution: apply a small inward offset (epsilon) to the device box
-    // before performing the boolean intersection.
-
-    gp_Vec epsilonVec = upDir;       
-    epsilonVec *= -1e-6;             
-    gp_Trsf trsf;
-    trsf.SetTranslation(epsilonVec);
-
-    BRepBuilderAPI_Transform transformer(shapeBox->Shape(), trsf, true);
-    TopoDS_Shape offsetBox = transformer.Shape();
-
-    PNamedShape shapeBoxOffset(new CNamedShape(offsetBox, shapeBox->Name().c_str()));
-
-
-    BRepAlgoAPI_Common common(wingCleanShape->Shape(), shapeBoxOffset->Shape());;
-    common.Build();
-
-    TopoDS_Shape outerShapeTopo = common.Shape();
-    PNamedShape outerShape(new CNamedShape(outerShapeTopo, shapeBox->Name().c_str()));
+    PNamedShape outerShape = CBopCommon(wingCleanShape, shapeBox);
 
     if (NeedsWingIntersection()) {
         return ControlSurfaceDeviceHelper::outerShapeGetLoft(shapeBox, outerShape, _uid);

src/ducts/CCPACSDuct.cpp

@@ -31,6 +31,8 @@ namespace tigl {
 CCPACSDuct::CCPACSDuct(CCPACSDucts* parent, CTiglUIDManager* uidMgr)
   : generated::CPACSDuct(parent, uidMgr)
   , CTiglRelativelyPositionedComponent(static_cast<std::string*>(nullptr), &m_transformation, &m_symmetry)
+  , loftUntrimmed(*this, &CCPACSDuct::BuildLoftUntrimmed)
+  , loftTrimmed(*this, &CCPACSDuct::BuildLoftTrimmed)
 {}
 
 CCPACSConfiguration& CCPACSDuct::GetConfiguration() const
@@ -55,31 +57,48 @@ TiglGeometricComponentIntent CCPACSDuct::GetComponentIntent() const
 }
 
 PNamedShape CCPACSDuct::BuildLoft() const
+{
+    return *loftUntrimmed;
+}
+
+void CCPACSDuct::BuildLoftUntrimmed(PNamedShape& cache) const
+{
+    BuildLoftImpl(cache, false);
+}
+
+void CCPACSDuct::BuildLoftTrimmed(PNamedShape& cache) const
+{
+    BuildLoftImpl(cache, true);
+}
+
+void CCPACSDuct::BuildLoftImpl(PNamedShape& cache, bool trim) const
 {
     TiglContinuity cont = m_segments.GetSegment(1).GetContinuity();
     Standard_Boolean smooth = (cont == ::C0? false : true);
 
     CTiglMakeLoft lofter;
-    // add profiles
+    lofter.setMakeSolid(true);
+    lofter.setMakeSmooth(smooth);
+    // Only the trimmed loft is cut at the profiles; the untrimmed loft is a
+    // single continuous surface.
+    lofter.setEnableProfileCutting(trim);
+
     for (int i=1; i <= m_segments.GetSegmentCount(); i++) {
         lofter.addProfiles(m_segments.GetSegment(i).GetStartWire());
     }
     lofter.addProfiles(m_segments.GetSegment(m_segments.GetSegmentCount()).GetEndWire());
 
-    // add guides
     lofter.addGuides(m_segments.GetGuideCurveWires());
 
-    lofter.setMakeSolid(true);
-    lofter.setMakeSmooth(smooth);
-
-    TopoDS_Shape loftShape =  lofter.Shape();
+    TopoDS_Shape loftShape = lofter.Shape();
 
     std::string loftName = GetUID();
     std::string loftShortName = GetShortShapeName();
-    PNamedShape loft(new CNamedShape(loftShape, loftName.c_str(), loftShortName.c_str()));
-    SetFaceTraits(loft);
+    cache = std::make_shared<CNamedShape>(loftShape, loftName.c_str(), loftShortName.c_str());
 
-    return loft;
+    // The trimmed loft has one face group per segment, whereas the untrimmed
+    // loft's aerodynamic faces form a single continuous group.
+    SetFaceTraits(cache, trim ? m_segments.GetSegmentCount() : 1);
 }
 
 // get short name for loft
@@ -100,8 +119,12 @@ std::string CCPACSDuct::GetShortShapeName() const
     return "UNKNOWN";
 }
 
-void CCPACSDuct::SetFaceTraits (PNamedShape loft) const
+void CCPACSDuct::SetFaceTraits(PNamedShape loft, int nSegments) const
 {
+    // Face layout: [aerodynamic faces][optional symmetry faces][front/rear caps].
+    // For the trimmed loft the aerodynamic (and symmetry) faces are grouped per
+    // segment (nSegments > 1); for the untrimmed loft they form a single group
+    // (nSegments == 1).
     int nFacesTotal = GetNumberOfFaces(loft->Shape());
     int nFacesAero = nFacesTotal;
     bool hasSymmetryPlane = GetNumberOfEdges(m_segments.GetSegment(1).GetEndWire()) > 1;
@@ -119,10 +142,7 @@ void CCPACSDuct::SetFaceTraits (PNamedShape loft) const
           nFacesAero-=1;
     }
 
-    // if we have a smooth surface, the whole fuslage is treatet as one segment
-    int nSegments = m_segments.GetSegmentCount();
-
-    int facesPerSegment = nFacesAero/ nSegments;
+    int facesPerSegment = FacesPerSegment(nFacesAero, nSegments);
 
     int iFaceTotal = 0;
     int nSymmetryFaces = (int) hasSymmetryPlane;
@@ -135,19 +155,34 @@ void CCPACSDuct::SetFaceTraits (PNamedShape loft) const
         }
     }
 
-    // set the caps
     int iFace = 2;
-    for (;iFaceTotal < nFacesTotal; ++iFaceTotal) {
-        loft->FaceTraits(iFaceTotal).SetName(names[iFace++].c_str());
+    for (;iFaceTotal < nFacesTotal; ++iFaceTotal, ++iFace) {
+        if (iFace < (int)names.size()) {
+            loft->FaceTraits(iFaceTotal).SetName(names[iFace].c_str());
+        }
     }
 }
 
+PNamedShape CCPACSDuct::GetUntrimmedLoft() const
+{
+    // GetLoft() returns the untrimmed loft, so this is the untrimmed loft by
+    // definition.
+    return GetLoft();
+}
+
+PNamedShape CCPACSDuct::GetTrimmedLoft() const
+{
+    return *loftTrimmed;
+}
+
 void CCPACSDuct::RegisterInvalidationCallback(std::function<void()> const& fn){
     invalidationCallbacks.push_back(fn);
 }
 
 void CCPACSDuct::InvalidateImpl(const boost::optional<std::string>&) const
 {
+    loftTrimmed.clear();
+    loftUntrimmed.clear();
     CTiglAbstractGeometricComponent::Reset();
     for (auto const& invalidator: invalidationCallbacks) {
         invalidator();

src/ducts/CCPACSDuct.h

@@ -45,6 +45,9 @@ class CCPACSDuct : public generated::CPACSDuct, public CTiglRelativelyPositioned
     //as a callback.
     TIGL_EXPORT void RegisterInvalidationCallback(std::function<void()> const&);
 
+    TIGL_EXPORT PNamedShape GetTrimmedLoft() const override;
+    TIGL_EXPORT PNamedShape GetUntrimmedLoft() const;
+
 protected:
     PNamedShape BuildLoft() const override;
 
@@ -55,10 +58,18 @@ class CCPACSDuct : public generated::CPACSDuct, public CTiglRelativelyPositioned
     // get short name for loft
     std::string GetShortShapeName() const;
 
-    void SetFaceTraits (PNamedShape loft) const;
+    // Names the loft's faces. nSegments controls whether the aerodynamic faces
+    // are grouped per segment (trimmed loft) or as a single group (untrimmed loft).
+    void SetFaceTraits (PNamedShape loft, int nSegments) const;
 
     std::vector<std::function<void()>> invalidationCallbacks;
 
+    mutable Cache<PNamedShape, CCPACSDuct> loftUntrimmed;   /**< Duct surface, untrimmed (without UV cuts at profiles) */
+    mutable Cache<PNamedShape, CCPACSDuct> loftTrimmed;     /**< Duct surface, trimmed (with UV cuts at profiles) */
+
+    void BuildLoftTrimmed(PNamedShape& cache) const;
+    void BuildLoftUntrimmed(PNamedShape& cache) const;
+    void BuildLoftImpl(PNamedShape& cache, bool trim) const;
 };
 
 }