diff -r 0347e9bc883e -r 5d2c9d36da9d src/toolsets/basictoolset.cpp
--- a/src/toolsets/basictoolset.cpp	Sat Mar 03 16:59:03 2018 +0200
+++ b/src/toolsets/basictoolset.cpp	Sat Mar 03 17:25:12 2018 +0200
@@ -220,7 +220,69 @@
 void BasicToolset::invert()
 {
 	for (LDObject* obj : selectedObjects())
-		obj->invert();
+	{
+		if (obj->numPolygonVertices() > 0)
+		{
+			QVector<Vertex> vertices;
+
+			for (int i = 0; i < obj->numPolygonVertices(); i += 1)
+				vertices.append(obj->vertex(i));
+
+			for (int i = 0; i < vertices.size(); i += 1)
+				obj->setVertex(i, vertices[vertices.size() - 1 - i]);
+		}
+		else if (obj->type() == LDObjectType::SubfileReference)
+		{
+			// Check whether subfile is flat
+			int axisSet = (1 << X) | (1 << Y) | (1 << Z);
+			Model model {currentDocument()->documentManager()};
+			LDSubfileReference* reference = static_cast<LDSubfileReference*>(obj);
+			reference->fileInfo()->inlineContents(model, true, false);
+
+			for (LDObject* subobj : model.objects())
+			{
+				for (int i = 0; i < subobj->numVertices(); ++i)
+				{
+					Vertex const& vrt = subobj->vertex (i);
+
+					if (axisSet & (1 << X) and vrt.x() != 0.0)
+						axisSet &= ~(1 << X);
+
+					if (axisSet & (1 << Y) and vrt.y() != 0.0)
+						axisSet &= ~(1 << Y);
+
+					if (axisSet & (1 << Z) and vrt.z() != 0.0)
+						axisSet &= ~(1 << Z);
+				}
+
+				if (axisSet == 0)
+					break;
+			}
+
+			if (axisSet != 0)
+			{
+				// Subfile has all vertices zero on one specific plane, so it is flat.
+				// Let's flip it.
+				Matrix matrixModifier = Matrix::identity;
+
+				if (axisSet & (1 << X))
+					matrixModifier(0, 0) = -1;
+
+				if (axisSet & (1 << Y))
+					matrixModifier(1, 1) = -1;
+
+				if (axisSet & (1 << Z))
+					matrixModifier(2, 2) = -1;
+
+				reference->setTransformationMatrix(reference->transformationMatrix() * matrixModifier);
+			}
+			else
+			{
+				// Subfile is not flat. Resort to invertnext.
+				reference->setInverted(not reference->isInverted());
+			}
+		}
+	}
 }
 
 void BasicToolset::newSubfile()