Gui: Fix empty sketch plane rendering

src/Base/Tools2D.h

@@ -119,6 +119,7 @@ public:
     inline BoundBox2d(double fX1, double fY1, double fX2, double fY2);
     ~BoundBox2d() = default;
     inline bool IsValid() const;
+    inline bool IsInfinite() const;
     inline bool IsEqual(const BoundBox2d& bbox, double tolerance) const;
 
     // operators
@@ -477,6 +478,11 @@ inline bool BoundBox2d::IsValid() const
     return (MaxX >= MinX) && (MaxY >= MinY);
 }
 
+inline bool BoundBox2d::IsInfinite() const
+{
+    return MaxX >= DOUBLE_MAX && MaxY >= DOUBLE_MAX && MinX <= -DOUBLE_MAX && MinY <= -DOUBLE_MAX;
+}
+
 inline bool BoundBox2d::IsEqual(const BoundBox2d& bbox, double tolerance) const
 {
     return Vector2d(MinX, MinY).IsEqual(Vector2d(bbox.MinX, bbox.MinY), tolerance)

src/Mod/Part/Gui/ViewProvider2DObject.cpp

@@ -396,6 +396,12 @@ void ViewProvider2DObject::updatePlane()
     Base::ViewOrthoProjMatrix proj(place.inverse().toMatrix());
     Base::BoundBox2d bb = bbox.ProjectBox(&proj);
 
+    // when projection of invalid it often results in infinite shapes
+    // if that happens we simply use some small bounding box to mark plane
+    if (bb.IsInfinite() || !bb.IsValid()) {
+        bb = Base::BoundBox2d(-1, -1, 1, 1);
+    }
+
     SbVec3f verts[4] = {
         SbVec3f(bb.MinX - horizontalPlanePadding, bb.MinY - verticalPlanePadding, 0),
         SbVec3f(bb.MinX - horizontalPlanePadding, bb.MaxY + verticalPlanePadding, 0),

src/Mod/Part/Gui/ViewProvider2DObject.h

@@ -42,7 +42,7 @@ class PartGuiExport ViewProvider2DObject : public PartGui::ViewProviderPart
     PROPERTY_HEADER_WITH_OVERRIDE(PartGui::ViewProvider2DObject);
 
     static constexpr float horizontalPlanePadding = 8;
-    static constexpr float verticalPlanePadding = 5;
+    static constexpr float verticalPlanePadding = 6;
 
 public:
     /// constructor