Require complete geometry for image and 3D exports

Report missing generated meshes and failed image writes, keep thumbnails and interactive geometry using their fallback behavior, and frame command-line images at the requested step or full range. Use explicit mesh loader flags and reject incomplete synthesized meshes. Keep selection and ray tests aligned with the rendered mesh.

common/lc_application.cpp

@@ -1148,15 +1148,28 @@ lcStartupMode lcApplication::Initialize(const QList<QPair<QString, bool>>& Libra
 				return lcStartupMode::Error;
 			}
 
-			if (Options.CameraName.isEmpty() && !Options.SetCameraPosition)
-				ActiveView->ZoomExtents();
+			const bool UsesCameraPosition = Options.SetCameraPosition && Options.Viewpoint == lcViewpoint::Count && !Options.SetCameraAngles;
+
+			if (Options.CameraName.isEmpty() && !UsesCameraPosition)
+			{
+				const lcStep FitStep = Options.ImageStart == Options.ImageEnd ? Options.ImageStart : ActiveModel->GetLastStep();
+
+				ActiveModel->ZoomExtentsAtStep(ActiveView->GetCamera(), (float)ActiveView->GetWidth() / (float)ActiveView->GetHeight(), FitStep);
+			}
 
 			auto ProgressCallback = [&StdOut](const QString& FileName)
 			{
 				StdOut << tr("Saved '%1'.\n").arg(FileName);
 			};
 
-			ActiveView->SaveStepImages(Frame, Options.ImageStart != Options.ImageEnd, Options.ImageStart, Options.ImageEnd, ProgressCallback);
+			const lcResult<void> ImagesSaved = ActiveView->SaveStepImages(Frame, Options.ImageStart != Options.ImageEnd, Options.ImageStart, Options.ImageEnd, ProgressCallback);
+
+			if (!ImagesSaved)
+			{
+				StdErr << ImagesSaved.error() << '\n';
+
+				return lcStartupMode::Error;
+			}
 		}
 
 		if (Options.SaveWavefront)

common/lc_blenderpreferences.cpp

@@ -3060,6 +3060,9 @@ void lcBlenderPreferences::SetModelSize(bool Update)
 		NativeImage& Image = Images.back();
 		Image.RenderedImage = Model->GetStepImage(false, ImageWidth, ImageHeight, Model->GetCurrentStep());
 
+		if (Image.RenderedImage.isNull())
+			return;
+
 		auto CalculateImageBounds = [](NativeImage& Image)
 		{
 			QImage& RenderedImage = Image.RenderedImage;

common/lc_instructionsdialog.cpp

@@ -25,6 +25,8 @@ void lcInstructionsStepImageItem::Update()
 
 	if (!Images.empty())
 		setPixmap(QPixmap::fromImage(Images.front()));
+	else
+		setPixmap(QPixmap());
 }
 
 lcInstructionsStepNumberItem::lcInstructionsStepNumberItem(QGraphicsItem* Parent, lcInstructions* Instructions, lcModel* Model, lcStep Step)

common/lc_library.cpp

@@ -401,7 +401,7 @@ PieceInfo* lcPiecesLibrary::FindPiece(const char* PieceName, Project* CurrentPro
 		if (ProjectFile.isFile())
 		{
 			Project* NewProject = new Project(CurrentProject && CurrentProject->IsPreview());
-			NewProject->SetStreamMeshes(CurrentProject && CurrentProject->UsesStreamingMeshes());
+			NewProject->SetDeferModelMeshRequests(CurrentProject && CurrentProject->DefersModelMeshRequests());
 
 			if (NewProject->Load(ProjectFile.absoluteFilePath(), false))
 			{
@@ -454,7 +454,7 @@ bool lcPiecesLibrary::RemapProjectPiece(PieceInfo* Info, const QString& ProjectD
 	if (Candidate.isFile())
 	{
 		Project* LocalProject = new Project(IsPreview);
-		LocalProject->SetStreamMeshes(true);
+		LocalProject->SetDeferModelMeshRequests(true);
 
 		if (LocalProject->Load(Candidate.absoluteFilePath(), false))
 			Info->CreateProject(LocalProject, PieceName.constData());
@@ -1771,7 +1771,7 @@ lcPartBuildResult lcPiecesLibrary::BuildPieceData(const lcPartSourceSnapshot& So
 
 		PieceFile.Seek(0, SEEK_SET);
 
-		lcMeshLoader MeshLoader(*Result.MeshData, true, nullptr, false);
+		lcMeshLoader MeshLoader(*Result.MeshData, nullptr, lcMeshLoaderFlag::Optimize);
 
 		if (!MeshLoader.LoadMesh(PieceFile, LC_MESHDATA_SHARED))
 		{
@@ -1812,7 +1812,7 @@ lcPartBuildResult lcPiecesLibrary::BuildPieceData(const lcPartSourceSnapshot& So
 
 	Result.MeshData.reset(new lcLibraryMeshData);
 
-	lcMeshLoader MeshLoader(*Result.MeshData, true, nullptr, false);
+	lcMeshLoader MeshLoader(*Result.MeshData, nullptr, lcMeshLoaderFlag::Optimize);
 
 	bool Loaded = false;
 
@@ -2337,7 +2337,7 @@ bool lcPiecesLibrary::LoadPrimitive(lcLibraryPrimitive* Primitive)
 		return false;
 	};
 
-	lcMeshLoader MeshLoader(Primitive->mMeshData, true, nullptr, false);
+	lcMeshLoader MeshLoader(Primitive->mMeshData, nullptr, lcMeshLoaderFlag::Optimize | lcMeshLoaderFlag::RequireAllIncludes);
 
 	if (mZipFiles[static_cast<int>(lcZipFileType::Official)])
 	{

common/lc_mainwindow.cpp

@@ -990,7 +990,6 @@ void lcMainWindow::UpdateAssets()
 	if (mStatusProject != Project)
 	{
 		mStatusProject = Project;
-		mHadPendingAssets = false;
 		mStatusRequiredAssets.clear();
 		mStatusLoadProgress->reset();
 		mStatusLoadProgress->setFormat(QString());
@@ -1016,7 +1015,6 @@ void lcMainWindow::UpdateAssets()
 
 	if (Required.empty())
 	{
-		mHadPendingAssets = false;
 		mStatusLoadProgress->reset();
 		mStatusLoadProgress->hide();
 		return;
@@ -1044,33 +1042,21 @@ void lcMainWindow::UpdateAssets()
 
 	if (Failed)
 	{
-		mHadPendingAssets = false;
 		mStatusLoadProgress->setFormat(tr("%n failed (%v/%m)", nullptr, Failed));
 		mStatusLoadProgress->setToolTip(FailureDetails);
 	}
 	else if (Pending)
 	{
-		mHadPendingAssets = true;
 		mStatusLoadProgress->setFormat(tr("Loading %v/%m"));
 	}
-	else if (mHadPendingAssets)
-	{
-		mHadPendingAssets = false;
-		mStatusLoadProgress->setFormat(tr("All pieces loaded"));
-		QTimer::singleShot(2500, this, [this, Project]()
-		{
-			if (mStatusProject == Project && !mHadPendingAssets && mStatusLoadProgress->format() == tr("All pieces loaded"))
-			{
-				mStatusLoadProgress->setFormat(QString());
-				mStatusLoadProgress->hide();
-			}
-		});
-	}
 	else
+	{
+		mStatusLoadProgress->setFormat(QString());
 		mStatusLoadProgress->hide();
+		return;
+	}
 
-	if (Failed || Pending || mStatusLoadProgress->format() == tr("All pieces loaded"))
-		mStatusLoadProgress->show();
+	mStatusLoadProgress->show();
 }
 
 void lcMainWindow::closeEvent(QCloseEvent* Event)
@@ -1389,6 +1375,12 @@ void lcMainWindow::Print(QPrinter* Printer)
 				lcStep Step = PageLayout.Steps[0].Step;
 				QImage Image = Model->GetStepImage(false, StepWidth, StepHeight, Step);
 
+				if (Image.isNull())
+				{
+					Printer->abort();
+					return;
+				}
+
 				Painter.drawImage(MarginRect.left(), MarginRect.top(), Image);
 
 				// TODO: add print options somewhere but Qt doesn't allow changes to the page setup dialog
@@ -1532,7 +1524,10 @@ void lcMainWindow::ShowImageDialog()
 	lcSetProfileInt(LC_PROFILE_IMAGE_WIDTH, Options.Width);
 	lcSetProfileInt(LC_PROFILE_IMAGE_HEIGHT, Options.Height);
 
-	lcGetActiveProject()->SaveImage(Options);
+	const lcResult<void> Saved = lcGetActiveProject()->SaveImage(Options);
+
+	if (!Saved)
+		QMessageBox::warning(this, tr("LeoCAD"), Saved.error());
 }
 
 void lcMainWindow::ShowSelectDialog()

common/lc_mainwindow.h

@@ -380,7 +380,6 @@ protected:
 	const Project* mStatusProject = nullptr;
 	std::unordered_set<const PieceInfo*> mStatusRequiredAssets;
 	bool mAssetUpdateScheduled = false;
-	bool mHadPendingAssets = false;
 
 	QMenu* mTransformMenu = nullptr;
 	QMenu* mToolsMenu = nullptr;

common/lc_meshloader.cpp

@@ -1052,7 +1052,7 @@ bool lcLibraryMeshData::WriteSections(lcMesh* Mesh, const std::vector<lcMeshLoad
 				if (TextureLookup)
 					DstSection.Texture = TextureLookup(FinalSection.Name);
 				else if (mMeshLoader)
-					DstSection.Texture = lcGetPiecesLibrary()->FindTexture(FinalSection.Name, mMeshLoader->mCurrentProject, mMeshLoader->mSearchProjectFolder);
+					DstSection.Texture = lcGetPiecesLibrary()->FindTexture(FinalSection.Name, mMeshLoader->mCurrentProject, mMeshLoader->SearchProjectFolder());
 				else
 					DstSection.Texture = lcGetPiecesLibrary()->FindTexture(FinalSection.Name, nullptr, false);
 			}
@@ -1226,8 +1226,8 @@ void lcLibraryMeshData::UpdateMeshSectionBoundingBox(const lcMesh* Mesh, const l
 	}
 }
 
-lcMeshLoader::lcMeshLoader(lcLibraryMeshData& MeshData, bool Optimize, Project* CurrentProject, bool SearchProjectFolder)
-	: mCurrentProject(CurrentProject), mSearchProjectFolder(SearchProjectFolder), mMeshData(MeshData), mOptimize(Optimize)
+lcMeshLoader::lcMeshLoader(lcLibraryMeshData& MeshData, Project* CurrentProject, lcMeshLoaderFlags Flags)
+	: mCurrentProject(CurrentProject), mMeshData(MeshData), mFlags(Flags)
 {
 	MeshData.SetMeshLoader(this);
 }
@@ -1247,6 +1247,7 @@ bool lcMeshLoader::ReadMeshData(lcFile& File, const lcMatrix44& CurrentTransform
 	bool InvertNext = false;
 	bool WindingCCW = !InvertWinding;
 	lcPiecesLibrary* Library = lcGetPiecesLibrary();
+	const bool Optimize = mFlags.testFlag(lcMeshLoaderFlag::Optimize);
 
 	while (File.ReadLine(Buffer, sizeof(Buffer)))
 	{
@@ -1539,18 +1540,28 @@ bool lcMeshLoader::ReadMeshData(lcFile& File, const lcMatrix44& CurrentTransform
 					mMeshData.AddMeshDataNoDuplicateCheck(Primitive->mMeshData, IncludeTransform, ColorCode, Mirror ^ InvertNext, InvertNext, TextureMap, MeshDataType);
 				else if (!Primitive->mSubFile)
 				{
-					if (mOptimize)
+					if (Optimize)
 						mMeshData.AddMeshData(Primitive->mMeshData, IncludeTransform, ColorCode, Mirror ^ InvertNext, InvertNext, TextureMap, MeshDataType);
 					else
 						mMeshData.AddMeshDataNoDuplicateCheck(Primitive->mMeshData, IncludeTransform, ColorCode, Mirror ^ InvertNext, InvertNext, TextureMap, MeshDataType);
 				}
 				else
+				{
+					if (mFlags.testFlag(lcMeshLoaderFlag::RequireAllIncludes))
+						IncludeLoaded = false;
+
 					Library->GetPrimitiveFile(Primitive, FileCallback);
+				}
 
 				mMeshData.mHasStyleStud |= Primitive->mStudStyle | Primitive->mMeshData.mHasStyleStud;
 			}
 			else
+			{
+				if (mFlags.testFlag(lcMeshLoaderFlag::RequireAllIncludes))
+					IncludeLoaded = false;
+
 				Library->GetPieceFile(FileName, FileCallback);
+			}
 
 			if (!IncludeLoaded)
 				return false;
@@ -1563,7 +1574,7 @@ bool lcMeshLoader::ReadMeshData(lcFile& File, const lcMatrix44& CurrentTransform
 			Points[0] = lcMul31(Points[0], CurrentTransform);
 			Points[1] = lcMul31(Points[1], CurrentTransform);
 
-			mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetMaterial(ColorCode), WindingCCW, Points, mOptimize);
+			mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetMaterial(ColorCode), WindingCCW, Points, Optimize);
 			break;
 
 		case 3:
@@ -1576,11 +1587,11 @@ bool lcMeshLoader::ReadMeshData(lcFile& File, const lcMatrix44& CurrentTransform
 			Points[2] = lcMul31(Points[2], CurrentTransform);
 
 			if (!TextureMap)
-				mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetMaterial(ColorCode), WindingCCW, Points, mOptimize);
+				mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetMaterial(ColorCode), WindingCCW, Points, Optimize);
 			else
 			{
 				mMeshData.mHasTextures = true;
-				mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetTexturedMaterial(ColorCode, *TextureMap), WindingCCW, Points, mOptimize);
+				mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetTexturedMaterial(ColorCode, *TextureMap), WindingCCW, Points, Optimize);
 
 			}
 			break;
@@ -1596,11 +1607,11 @@ bool lcMeshLoader::ReadMeshData(lcFile& File, const lcMatrix44& CurrentTransform
 			Points[3] = lcMul31(Points[3], CurrentTransform);
 
 			if (!TextureMap)
-				mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetMaterial(ColorCode), WindingCCW, Points, mOptimize);
+				mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetMaterial(ColorCode), WindingCCW, Points, Optimize);
 			else
 			{
 				mMeshData.mHasTextures = true;
-				mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetTexturedMaterial(ColorCode, *TextureMap), WindingCCW, Points, mOptimize);
+				mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetTexturedMaterial(ColorCode, *TextureMap), WindingCCW, Points, Optimize);
 
 			}
 			break;
@@ -1615,7 +1626,7 @@ bool lcMeshLoader::ReadMeshData(lcFile& File, const lcMatrix44& CurrentTransform
 			Points[2] = lcMul31(Points[2], CurrentTransform);
 			Points[3] = lcMul31(Points[3], CurrentTransform);
 
-			mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetMaterial(ColorCode), WindingCCW, Points, mOptimize);
+			mMeshData.mData[MeshDataType].ProcessLine(LineType, mMeshData.GetMaterial(ColorCode), WindingCCW, Points, Optimize);
 			break;
 		}
 

common/lc_meshloader.h

@@ -201,15 +201,26 @@ protected:
 	static void UpdateMeshSectionBoundingBox(const lcMesh* Mesh, const lcMeshSection& Section, lcVector3& SectionMin, lcVector3& SectionMax);
 };
 
+enum class lcMeshLoaderFlag
+{
+	None = 0,
+	Optimize = 1 << 0,
+	SearchProjectFolder = 1 << 1,
+	RequireAllIncludes = 1 << 2
+};
+
+Q_DECLARE_FLAGS(lcMeshLoaderFlags, lcMeshLoaderFlag)
+Q_DECLARE_OPERATORS_FOR_FLAGS(lcMeshLoaderFlags)
+
 class lcMeshLoader
 {
 public:
-	lcMeshLoader(lcLibraryMeshData& MeshData, bool Optimize, Project* CurrentProject, bool SearchProjectFolder);
+	lcMeshLoader(lcLibraryMeshData& MeshData, Project* CurrentProject, lcMeshLoaderFlags Flags);
 
 	bool LoadMesh(lcFile& File, lcMeshDataType MeshDataType);
+	bool SearchProjectFolder() const { return mFlags.testFlag(lcMeshLoaderFlag::SearchProjectFolder); }
 
 	Project* mCurrentProject;
-	bool mSearchProjectFolder;
 
 protected:
 	bool ReadMeshData(lcFile& File, const lcMatrix44& CurrentTransform, quint32 CurrentColorCode, bool InvertWinding, lcMeshDataType MeshDataType);
@@ -217,5 +228,5 @@ protected:
 	std::vector<lcMeshLoaderTextureMap> mTextureStack;
 
 	lcLibraryMeshData& mMeshData;
-	bool mOptimize;
+	lcMeshLoaderFlags mFlags;
 };

common/lc_model.cpp

@@ -388,9 +388,9 @@ void lcModel::CreatePieceInfo(Project* Project)
 		}), mPieces.end());
 	}
 
-	// A streamed external model retains its initial CreateModelPiece reference
+	// A model with deferred mesh requests retains its initial CreateModelPiece reference
 	// until its source lines have been parsed and QueueMeshBuild() runs.
-	if (!Project->UsesStreamingMeshes())
+	if (!Project->DefersModelMeshRequests())
 	{
 		Library->LoadPieceInfo(mPieceInfo, mIsPreview ? lcPieceLoadFlag::Visible : lcPieceLoadFlag::Wait | lcPieceLoadFlag::Visible);
 		Library->ReleasePieceInfo(mPieceInfo);
@@ -400,7 +400,7 @@ void lcModel::CreatePieceInfo(Project* Project)
 	{
 		UpdateAllViews();
 
-		if (!Project->UsesStreamingMeshes())
+		if (!Project->DefersModelMeshRequests())
 			RefreshPreview();
 	}
 }
@@ -1657,25 +1657,51 @@ QImage lcModel::GetStepImage(bool Zoom, int Width, int Height, lcStep Step)
 		return QImage();
 	}
 
-	const lcView* ActiveView = gMainWindow->GetActiveView();
-	const lcStep CurrentStep = mCurrentStep;
-	lcCamera* Camera = ActiveView->GetCamera();
+	const lcResult<QImage> Image = RenderStepImageWithReadyAssets(Zoom, Width, Height, Step, nullptr);
 
-	lcView View(lcViewType::View, this);
-	View.SetCamera(Camera, true);
-	View.SetOffscreenContext();
-	View.MakeCurrent();
-
-	if (!View.BeginRenderToImage(Width, Height))
+	if (!Image)
 	{
-		QMessageBox::warning(gMainWindow, tr("LeoCAD"), tr("Error creating images."));
+		if (gMainWindow)
+			QMessageBox::warning(gMainWindow, tr("LeoCAD"), Image.error());
+
 		return QImage();
 	}
 
+	return Image.value();
+}
+
+lcResult<QImage> lcModel::RenderStepImageWithReadyAssets(bool Zoom, int Width, int Height, lcStep Step, lcCamera* OutputCamera)
+{
+	const lcView* ActiveView = gMainWindow ? gMainWindow->GetActiveView() : nullptr;
+	const lcStep CurrentStep = mCurrentStep;
+
+	lcView View(lcViewType::View, this);
+
+	if (OutputCamera)
+		View.SetCamera(OutputCamera, true);
+	else if (ActiveView)
+		View.SetCamera(ActiveView->GetCamera(), true);
+
+	View.SetOffscreenContext();
+	View.MakeCurrent();
+
+	if (!OutputCamera && !ActiveView)
+		ZoomExtentsAtStep(View.GetCamera(), (float)Width / (float)Height, GetLastStep());
+
 	SetTemporaryStep(Step);
 
-	if (Zoom)
-		ZoomExtents(Camera, (float)Width / (float)Height, lcMatrix44Identity());
+	if (Zoom && ActiveView && !OutputCamera)
+		ZoomExtents(View.GetCamera(), (float)Width / (float)Height, lcMatrix44Identity());
+
+	if (!View.BeginRenderToImage(Width, Height))
+	{
+		SetTemporaryStep(CurrentStep);
+
+		if (!mActive)
+			CalculateStep(LC_STEP_MAX);
+
+		return lcUnexpected(tr("Error creating images."));
+	}
 
 	View.OnDraw();
 
@@ -1693,8 +1719,8 @@ QImage lcModel::GetStepImage(bool Zoom, int Width, int Height, lcStep Step)
 	if (!mActive)
 		CalculateStep(LC_STEP_MAX);
 
-	if (MissingAssets && gMainWindow)
-		QMessageBox::warning(gMainWindow, tr("LeoCAD"), tr("Could not render all required pieces."));
+	if (MissingAssets || Image.isNull())
+		return lcUnexpected(tr("Could not render all required pieces."));
 
 	return Image;
 }
@@ -1765,7 +1791,9 @@ QImage lcModel::GetPartsListImage(int MaxWidth, lcStep Step, quint32 BackgroundC
 
 	if (!View.BeginRenderToImage(ThumbnailSize, ThumbnailSize))
 	{
-		QMessageBox::warning(gMainWindow, tr("LeoCAD"), tr("Error creating images."));
+		if (gMainWindow)
+			QMessageBox::warning(gMainWindow, tr("LeoCAD"), tr("Error creating images."));
+
 		return QImage();
 	}
 
@@ -1946,16 +1974,21 @@ QImage lcModel::GetPartsListImage(int MaxWidth, lcStep Step, quint32 BackgroundC
 	return PainterImage;
 }
 
-void lcModel::SaveStepImages(const QString& BaseName, bool AddStepSuffix, bool Zoom, int Width, int Height, lcStep Start, lcStep End)
+lcResult<void> lcModel::SaveStepImages(const QString& BaseName, bool AddStepSuffix, bool Zoom, int Width, int Height, lcStep Start, lcStep End)
 {
 	const lcResult<void> Ready = EnsureAssetsReady();
 
 	if (!Ready)
-	{
-		if (gMainWindow)
-			QMessageBox::warning(gMainWindow, tr("LeoCAD"), Ready.error());
+		return Ready;
 
-		return;
+	lcCamera OutputCamera(true);
+	lcCamera* Camera = nullptr;
+
+	if (!gMainWindow || !gMainWindow->GetActiveView())
+	{
+		OutputCamera.SetViewpoint(lcViewpoint::Home);
+		ZoomExtentsAtStep(&OutputCamera, (float)Width / (float)Height, GetLastStep());
+		Camera = &OutputCamera;
 	}
 
 	for (lcStep Step = Start; Step <= End; Step++)
@@ -1967,18 +2000,21 @@ void lcModel::SaveStepImages(const QString& BaseName, bool AddStepSuffix, bool Z
 		else
 			FileName = BaseName;
 
+		const lcResult<QImage> Image = RenderStepImageWithReadyAssets(Zoom, Width, Height, Step, Camera);
+
+		if (!Image)
+			return lcUnexpected(Image.error());
+
 		QImageWriter Writer(FileName);
 
 		if (Writer.format().isEmpty())
 			Writer.setFormat("png");
 
-		QImage Image = GetStepImage(Zoom, Width, Height, Step);
-		if (!Writer.write(Image))
-		{
-			QMessageBox::information(gMainWindow, tr("Error"), tr("Error writing to file '%1':\n%2").arg(FileName, Writer.errorString()));
-			break;
-		}
+		if (!Writer.write(Image.value()))
+			return lcUnexpected(tr("Error writing to file '%1':\n%2").arg(FileName, Writer.errorString()));
 	}
+
+	return lcResult<void>();
 }
 
 void lcModel::RayTest(lcObjectRayTest& ObjectRayTest) const
@@ -2026,7 +2062,7 @@ bool lcModel::SubModelMinIntersectDist(const lcVector3& WorldStart, const lcVect
 
 		if (Piece->IsVisibleInSubModel())
 		{
-			if (Piece->mPieceInfo->MinIntersectDist(Start, End, MinDistance, PieceInfoRayTest)) // todo: this should check for piece->mMesh first
+			if (Piece->MinIntersectDist(Start, End, MinDistance, PieceInfoRayTest))
 			{
 				MinIntersect = true;
 				PieceInfoRayTest.Transform = lcMul(PieceInfoRayTest.Transform, Piece->mModelWorld);
@@ -2040,7 +2076,7 @@ bool lcModel::SubModelMinIntersectDist(const lcVector3& WorldStart, const lcVect
 bool lcModel::SubModelBoxTest(const lcVector4 Planes[6]) const
 {
 	for (const std::unique_ptr<lcPiece>& Piece : mPieces)
-		if (Piece->IsVisibleInSubModel() && Piece->mPieceInfo->BoxTest(Piece->mModelWorld, Planes))
+		if (Piece->IsVisibleInSubModel() && Piece->IntersectsPlanes(Piece->mModelWorld, Planes))
 			return true;
 
 	return false;
@@ -5964,6 +6000,18 @@ void lcModel::ZoomExtents(lcCamera* Camera, float Aspect, const lcMatrix44& Worl
 	}
 }
 
+void lcModel::ZoomExtentsAtStep(lcCamera* Camera, float Aspect, lcStep Step)
+{
+	const lcStep CurrentStep = mCurrentStep;
+
+	SetTemporaryStep(Step);
+	ZoomExtents(Camera, Aspect, lcMatrix44Identity());
+	SetTemporaryStep(CurrentStep);
+
+	if (!mActive)
+		CalculateStep(LC_STEP_MAX);
+}
+
 void lcModel::Zoom(lcCamera* Camera, float Amount)
 {
 	if (!Camera->IsSimple())

common/lc_model.h

@@ -331,7 +331,7 @@ public:
 	void AddSubModelRenderMeshes(lcScene* Scene, const lcMatrix44& WorldMatrix, int DefaultColorIndex, lcRenderMeshState RenderMeshState, bool ParentActive) const;
 	QImage GetStepImage(bool Zoom, int Width, int Height, lcStep Step);
 	QImage GetPartsListImage(int MaxWidth, lcStep Step, quint32 BackgroundColor, QFont Font, QColor TextColor) const;
-	void SaveStepImages(const QString& BaseName, bool AddStepSuffix, bool Zoom, int Width, int Height, lcStep Start, lcStep End);
+	lcResult<void> SaveStepImages(const QString& BaseName, bool AddStepSuffix, bool Zoom, int Width, int Height, lcStep Start, lcStep End);
 
 	void RayTest(lcObjectRayTest& ObjectRayTest) const;
 	void BoxTest(lcObjectBoxTest& ObjectBoxTest) const;
@@ -423,6 +423,7 @@ public:
 	void LookAt(lcCamera* Camera);
 	void MoveCamera(lcCamera* Camera, const lcVector3& Direction);
 	void ZoomExtents(lcCamera* Camera, float Aspect, const lcMatrix44& WorldMatrix);
+	void ZoomExtentsAtStep(lcCamera* Camera, float Aspect, lcStep Step);
 	void Zoom(lcCamera* Camera, float Amount);
 
 	void MoveSelectedObjects(const lcVector3& Distance, lcModelTransformFlags Flags, lcModelHistoryEditMerge ModelHistoryEditMerge)
@@ -452,6 +453,8 @@ public:
 	void UpdateInterface();
 
 protected:
+	lcResult<QImage> RenderStepImageWithReadyAssets(bool Zoom, int Width, int Height, lcStep Step, lcCamera* OutputCamera);
+
 	void DeleteModel();
 
 	void AddSelectionHistory(std::function<void()> Callback);

common/lc_scene.h

@@ -68,6 +68,16 @@ public:
 		return mRequireCompleteAssets;
 	}
 
+	void SetRequireGeneratedMeshes(bool RequireGeneratedMeshes)
+	{
+		mRequireGeneratedMeshes = RequireGeneratedMeshes;
+	}
+
+	bool GetRequireGeneratedMeshes() const
+	{
+		return mRequireGeneratedMeshes;
+	}
+
 	void MarkMissingAssets()
 	{
 		mMissingAssets = true;
@@ -136,6 +146,7 @@ protected:
 	lcShadingMode mShadingMode;
 	bool mDrawInterface = false;
 	bool mRequireCompleteAssets = false;
+	bool mRequireGeneratedMeshes = false;
 	bool mMissingAssets = false;
 	bool mDrawInsertPreview = false;
 	bool mAllowLOD = true;

common/lc_synth.cpp

@@ -1526,8 +1526,8 @@ lcMesh* lcSynthInfo::CreateMesh(const std::vector<lcPieceControlPoint>& ControlP
 	File.WriteU8(0);
 	File.Seek(0, SEEK_SET);
 
-	lcMeshLoader MeshLoader(MeshData, false, nullptr, false);
-	if (MeshLoader.LoadMesh(File, LC_MESHDATA_SHARED))
+	lcMeshLoader MeshLoader(MeshData, nullptr, lcMeshLoaderFlag::RequireAllIncludes);
+	if (MeshLoader.LoadMesh(File, LC_MESHDATA_SHARED) && !MeshData.IsEmpty())
 		return MeshData.CreateMesh();
 
 	return nullptr;

common/lc_thumbnailmanager.cpp

@@ -256,6 +256,7 @@ void lcThumbnailManager::DrawThumbnail(lcPartThumbnailId ThumbnailId, lcPartThum
 		if (!mView->BeginRenderToImage(Width, Height))
 		{
 			mView.reset();
+			DrawFailedThumbnail(ThumbnailId, Thumbnail);
 			return;
 		}
 	}
@@ -293,6 +294,13 @@ void lcThumbnailManager::DrawThumbnail(lcPartThumbnailId ThumbnailId, lcPartThum
 	}
 
 	QImage Image = mView->GetRenderImage().convertToFormat(QImage::Format_ARGB32);
+
+	if (Image.isNull())
+	{
+		DrawFailedThumbnail(ThumbnailId, Thumbnail);
+		return;
+	}
+
 	const char* IconName = nullptr;
 
 	if (Info->GetSynthInfo())

common/lc_view.cpp

@@ -734,7 +734,9 @@ std::vector<QImage> lcView::GetStepImages(lcStep Start, lcStep End)
 
 	if (!BeginRenderToImage(mWidth, mHeight))
 	{
-		QMessageBox::warning(gMainWindow, tr("LeoCAD"), tr("Error creating images."));
+		if (gMainWindow)
+			QMessageBox::warning(gMainWindow, tr("LeoCAD"), tr("Error creating images."));
+
 		return Images;
 	}
 
@@ -754,7 +756,16 @@ std::vector<QImage> lcView::GetStepImages(lcStep Start, lcStep End)
 			break;
 		}
 
-		Images.emplace_back(GetRenderImage());
+		QImage Image = GetRenderImage();
+
+		if (Image.isNull())
+		{
+			MissingAssets = true;
+			Images.clear();
+			break;
+		}
+
+		Images.emplace_back(std::move(Image));
 	}
 
 	EndRenderToImage();
@@ -770,12 +781,12 @@ std::vector<QImage> lcView::GetStepImages(lcStep Start, lcStep End)
 	return Images;
 }
 
-void lcView::SaveStepImages(const QString& BaseName, bool AddStepSuffix, lcStep Start, lcStep End, std::function<void(const QString&)> ProgressCallback)
+lcResult<void> lcView::SaveStepImages(const QString& BaseName, bool AddStepSuffix, lcStep Start, lcStep End, std::function<void(const QString&)> ProgressCallback)
 {
 	std::vector<QImage> Images = GetStepImages(Start, End);
 
 	if (Images.size() != static_cast<size_t>(End - Start + 1))
-		return;
+		return lcUnexpected(tr("Could not render all required pieces."));
 
 	for (lcStep Step = Start; Step <= End; Step++)
 	{
@@ -792,14 +803,13 @@ void lcView::SaveStepImages(const QString& BaseName, bool AddStepSuffix, lcStep
 			Writer.setFormat("png");
 
 		if (!Writer.write(Images[Step - Start]))
-		{
-			QMessageBox::information(gMainWindow, tr("Error"), tr("Error writing to file '%1':\n%2").arg(FileName, Writer.errorString()));
-			break;
-		}
+			return lcUnexpected(tr("Error writing to file '%1':\n%2").arg(FileName, Writer.errorString()));
 
 		if (ProgressCallback)
 			ProgressCallback(FileName);
 	}
+
+	return lcResult<void>();
 }
 
 bool lcView::BeginRenderToImage(int Width, int Height)
@@ -896,6 +906,7 @@ void lcView::OnDraw()
 	mScene->SetShadingMode(ShadingMode);
 	mScene->SetAllowLOD(Preferences.mAllowLOD && mWidget != nullptr);
 	mScene->SetRequireCompleteAssets(static_cast<bool>(mRenderFramebuffer));
+	mScene->SetRequireGeneratedMeshes(mRenderFramebuffer && mViewType != lcViewType::PartsList);
 	mScene->SetLODDistance(Preferences.mMeshLODDistance);
 
 	mScene->Begin(mCamera->mWorldView);

common/lc_view.h

@@ -3,6 +3,7 @@
 #include "lc_context.h"
 #include "lc_math.h"
 #include "lc_commands.h"
+#include "lc_result.h"
 
 struct lcInsertPieceInfo;
 enum class lcCameraProjection;
@@ -304,7 +305,7 @@ public:
 	void UnbindRenderFramebuffer();
 	QImage GetRenderFramebufferImage() const;
 	std::vector<QImage> GetStepImages(lcStep Start, lcStep End);
-	void SaveStepImages(const QString& BaseName, bool AddStepSuffix, lcStep Start, lcStep End, std::function<void(const QString&)> ProgressCallback);
+	lcResult<void> SaveStepImages(const QString& BaseName, bool AddStepSuffix, lcStep Start, lcStep End, std::function<void(const QString&)> ProgressCallback);
 
 	lcContext* mContext = nullptr;
 

common/piece.cpp

@@ -480,23 +480,11 @@ void lcPiece::RayTest(lcObjectRayTest& ObjectRayTest) const
 	const lcVector3 Start = lcMul31(ObjectRayTest.Start, InverseWorldMatrix);
 	const lcVector3 End = lcMul31(ObjectRayTest.End, InverseWorldMatrix);
 
-	if (mMesh && !mPieceInfo->IsLoading())
+	if (MinIntersectDist(Start, End, ObjectRayTest.Distance, ObjectRayTest.PieceInfoRayTest))
 	{
-		if (mMesh->MinIntersectDist(Start, End, ObjectRayTest.Distance, ObjectRayTest.PieceInfoRayTest.Plane))
-		{
-			ObjectRayTest.ObjectSection.Object = const_cast<lcPiece*>(this);
-			ObjectRayTest.ObjectSection.Section = LC_PIECE_SECTION_POSITION;
-			ObjectRayTest.PieceInfoRayTest.Transform = mModelWorld;
-		}
-	}
-	else
-	{
-		if (mPieceInfo->MinIntersectDist(Start, End, ObjectRayTest.Distance, ObjectRayTest.PieceInfoRayTest))
-		{
-			ObjectRayTest.ObjectSection.Object = const_cast<lcPiece*>(this);
-			ObjectRayTest.ObjectSection.Section = LC_PIECE_SECTION_POSITION;
-			ObjectRayTest.PieceInfoRayTest.Transform = lcMul(ObjectRayTest.PieceInfoRayTest.Transform, mModelWorld);
-		}
+		ObjectRayTest.ObjectSection.Object = const_cast<lcPiece*>(this);
+		ObjectRayTest.ObjectSection.Section = LC_PIECE_SECTION_POSITION;
+		ObjectRayTest.PieceInfoRayTest.Transform = lcMul(ObjectRayTest.PieceInfoRayTest.Transform, mModelWorld);
 	}
 
 	if (mPieceInfo->GetSynthInfo() && AreControlPointsVisible())
@@ -524,12 +512,67 @@ void lcPiece::RayTest(lcObjectRayTest& ObjectRayTest) const
 	}
 }
 
+bool lcPiece::MinIntersectDist(const lcVector3& Start, const lcVector3& End, float& MinDistance, lcPieceInfoRayTest& PieceInfoRayTest) const
+{
+	if (!mMesh || mPieceInfo->IsLoading())
+		return mPieceInfo->MinIntersectDist(Start, End, MinDistance, PieceInfoRayTest);
+
+	if (!mMesh->MinIntersectDist(Start, End, MinDistance, PieceInfoRayTest.Plane))
+		return false;
+
+	PieceInfoRayTest.Info = mPieceInfo;
+	PieceInfoRayTest.Transform = lcMatrix44Identity();
+
+	return true;
+}
+
 void lcPiece::BoxTest(lcObjectBoxTest& ObjectBoxTest) const
 {
-	if (mPieceInfo->BoxTest(mModelWorld, ObjectBoxTest.Planes))
+	if (IntersectsPlanes(mModelWorld, ObjectBoxTest.Planes))
 		ObjectBoxTest.Objects.emplace_back(const_cast<lcPiece*>(this));
 }
 
+bool lcPiece::IntersectsPlanes(const lcMatrix44& WorldMatrix, const lcVector4 Planes[6]) const
+{
+	if (!mMesh || mPieceInfo->IsLoading())
+		return mPieceInfo->BoxTest(WorldMatrix, Planes);
+
+	const lcMatrix44 InverseWorldMatrix = lcMatrix44AffineInverse(WorldMatrix);
+	lcVector4 LocalPlanes[6];
+
+	for (int PlaneIdx = 0; PlaneIdx < 6; PlaneIdx++)
+	{
+		const lcVector3 PlaneNormal = lcMul30(Planes[PlaneIdx], InverseWorldMatrix);
+		LocalPlanes[PlaneIdx] = lcVector4(PlaneNormal, Planes[PlaneIdx][3] - lcDot3(InverseWorldMatrix[3], PlaneNormal));
+	}
+
+	lcVector3 Corners[8];
+	lcGetBoxCorners(mMesh->mBoundingBox, Corners);
+
+	int OutcodesOR = 0;
+	int OutcodesAND = 0x3f;
+
+	for (const lcVector3& Corner : Corners)
+	{
+		int Outcode = 0;
+
+		for (int PlaneIdx = 0; PlaneIdx < 6; PlaneIdx++)
+			if (lcDot3(Corner, LocalPlanes[PlaneIdx]) + LocalPlanes[PlaneIdx][3] > 0)
+				Outcode |= 1 << PlaneIdx;
+
+		OutcodesOR |= Outcode;
+		OutcodesAND &= Outcode;
+	}
+
+	if (OutcodesAND != 0)
+		return false;
+
+	if (OutcodesOR == 0)
+		return true;
+
+	return mMesh->IntersectsPlanes(LocalPlanes);
+}
+
 void lcPiece::DrawInterface(lcContext* Context, const lcScene& Scene) const
 {
 	const lcPreferences& Preferences = lcGetPreferences();
@@ -1012,7 +1055,12 @@ void lcPiece::AddMainModelRenderMeshes(lcScene* Scene, bool Highlight, bool Fade
 	}
 
 	if (!mMesh || mPieceInfo->IsLoading())
+	{
+		if (!mMesh && mPieceInfo->GetSynthInfo() && Scene->GetRequireGeneratedMeshes())
+			Scene->MarkMissingAssets();
+
 		mPieceInfo->AddRenderMeshes(Scene, mModelWorld, mColorIndex, RenderMeshState, ParentActive);
+	}
 	else
 		Scene->AddMesh(mMesh, mModelWorld, mColorIndex, RenderMeshState);
 
@@ -1035,7 +1083,12 @@ void lcPiece::AddSubModelRenderMeshes(lcScene* Scene, const lcMatrix44& WorldMat
 		RenderMeshState = IsFocused() ? lcRenderMeshState::Focused : (IsSelected() ? lcRenderMeshState::Selected : lcRenderMeshState::Default);
 
 	if (!mMesh || mPieceInfo->IsLoading())
+	{
+		if (!mMesh && mPieceInfo->GetSynthInfo() && Scene->GetRequireGeneratedMeshes())
+			Scene->MarkMissingAssets();
+
 		mPieceInfo->AddRenderMeshes(Scene, lcMul(mModelWorld, WorldMatrix), ColorIndex, RenderMeshState, ActiveSubmodelInstance == this);
+	}
 	else
 		Scene->AddMesh(mMesh, lcMul(mModelWorld, WorldMatrix), ColorIndex, RenderMeshState);
 

common/piece.h

@@ -85,6 +85,8 @@ public:
 
 	void RayTest(lcObjectRayTest& ObjectRayTest) const override;
 	void BoxTest(lcObjectBoxTest& ObjectBoxTest) const override;
+	bool MinIntersectDist(const lcVector3& Start, const lcVector3& End, float& MinDistance, lcPieceInfoRayTest& PieceInfoRayTest) const;
+	bool IntersectsPlanes(const lcMatrix44& WorldMatrix, const lcVector4 Planes[6]) const;
 	void DrawInterface(lcContext* Context, const lcScene& Scene) const override;
 	QVariant GetPropertyValue(lcObjectPropertyId PropertyId) const override;
 	bool SetPropertyValue(lcObjectPropertyId PropertyId, lcStep Step, bool AddKey, QVariant Value) override;

common/project.cpp

@@ -710,7 +710,7 @@ bool Project::Load(const QString& FileName, bool ShowErrors)
 		}
 		else
 		{
-			if (mStreamMeshes)
+			if (mDeferModelMeshRequests)
 				lcGetPiecesLibrary()->InvalidatePiece(Model->GetPieceInfo());
 
 			Model->QueueMeshBuild();
@@ -1118,7 +1118,7 @@ bool Project::ImportInventory(const std::vector<lcSetInventoryItem>& SetInventor
 	return true;
 }
 
-std::vector<lcModelPartsEntry> Project::GetModelParts()
+lcResult<std::vector<lcModelPartsEntry>> Project::GetModelParts()
 {
 	std::vector<lcModelPartsEntry> ModelParts;
 
@@ -1132,7 +1132,13 @@ std::vector<lcModelPartsEntry> Project::GetModelParts()
 
 	SetActiveModel(mActiveModel, false);
 
-	return ModelParts;
+	for (const lcModelPartsEntry& ModelPart : ModelParts)
+	{
+		if (ModelPart.Info->GetSynthInfo() && !ModelPart.Mesh)
+			return lcUnexpected(tr("Could not generate geometry for piece '%1'.").arg(QString::fromLatin1(ModelPart.Info->mFileName)));
+	}
+
+	return std::move(ModelParts);
 }
 
 std::vector<PieceInfo*> Project::GetRequiredPieces() const
@@ -1304,7 +1310,12 @@ lcResult<void> Project::Export3DStudio(const QString& FileName)
 	if (!Ready)
 		return Ready;
 
-	std::vector<lcModelPartsEntry> ModelParts = GetModelParts();
+	const lcResult<std::vector<lcModelPartsEntry>> ModelPartsResult = GetModelParts();
+
+	if (!ModelPartsResult)
+		return lcUnexpected(ModelPartsResult.error());
+
+	const std::vector<lcModelPartsEntry>& ModelParts = ModelPartsResult.value();
 
 	if (ModelParts.empty())
 		return lcUnexpected(tr("Nothing to export."));
@@ -1762,7 +1773,12 @@ lcResult<void> Project::ExportCOLLADA(const QString& FileName)
 	if (!Ready)
 		return Ready;
 
-	std::vector<lcModelPartsEntry> ModelParts = GetModelParts();
+	const lcResult<std::vector<lcModelPartsEntry>> ModelPartsResult = GetModelParts();
+
+	if (!ModelPartsResult)
+		return lcUnexpected(ModelPartsResult.error());
+
+	const std::vector<lcModelPartsEntry>& ModelParts = ModelPartsResult.value();
 
 	if (ModelParts.empty())
 		return lcUnexpected(tr("Nothing to export."));
@@ -2104,19 +2120,33 @@ lcResult<void> Project::ExportHTML(const lcHTMLExportOptions& Options)
 
 	QString ProjectTitle = GetTitle();
 
-	auto AddPartsListImage = [&Dir](QTextStream& Stream, lcModel* Model, lcStep Step, const QString& BaseName)
+	auto AddPartsListImage = [&Dir](QTextStream& Stream, lcModel* Model, lcStep Step, const QString& BaseName) -> lcResult<void>
 	{
+		lcPartsList PartsList;
+
+		if (Step == 0)
+			Model->GetPartsList(gDefaultColor, true, false, PartsList);
+		else
+			Model->GetPartsListForStep(Step, gDefaultColor, PartsList, false);
+
+		if (PartsList.empty())
+			return lcResult<void>();
+
 		QImage Image = Model->GetPartsListImage(1024, Step, LC_RGBA(255, 255, 255, 0), QFont("Arial", 16, QFont::Bold), Qt::black);
 
-		if (!Image.isNull())
-		{
-			QString ImageName = BaseName + QLatin1String("-parts.png");
-			QString FileName = QFileInfo(Dir, ImageName).absoluteFilePath();
+		if (Image.isNull())
+			return lcUnexpected(tr("Could not render the pieces list image."));
 
-			Image.save(FileName);
+		QString ImageName = BaseName + QLatin1String("-parts.png");
+		QString FileName = QFileInfo(Dir, ImageName).absoluteFilePath();
+		QImageWriter Writer(FileName);
 
-			Stream << QString::fromLatin1("<p><IMG SRC=\"%1\" /></p><br><br>\r\n").arg(ImageName);
-		}
+		if (!Writer.write(Image))
+			return lcUnexpected(tr("Error writing to file '%1':\n%2").arg(FileName, Writer.errorString()));
+
+		Stream << QString::fromLatin1("<p><IMG SRC=\"%1\" /></p><br><br>\r\n").arg(ImageName);
+
+		return lcResult<void>();
 	};
 
 	for (lcModel* Model : Models)
@@ -2152,11 +2182,21 @@ lcResult<void> Project::ExportHTML(const lcHTMLExportOptions& Options)
 				Stream << QString::fromLatin1("<p><IMG SRC=\"%1-%2.png\" ALT=\"Step %3\" WIDTH=%4 HEIGHT=%5></p><BR><BR>\r\n").arg(BaseName, StepString, StepString, QString::number(Options.StepImagesWidth), QString::number(Options.StepImagesHeight));
 
 				if (Options.PartsListStep)
-					AddPartsListImage(Stream, Model, Step, QString("%1-%2").arg(BaseName, StepString));
+				{
+					const lcResult<void> PartsImageSaved = AddPartsListImage(Stream, Model, Step, QString("%1-%2").arg(BaseName, StepString));
+
+					if (!PartsImageSaved)
+						return PartsImageSaved;
+				}
 			}
 
 			if (Options.PartsListEnd)
-				AddPartsListImage(Stream, Model, 0, BaseName);
+			{
+				const lcResult<void> PartsImageSaved = AddPartsListImage(Stream, Model, 0, BaseName);
+
+				if (!PartsImageSaved)
+					return PartsImageSaved;
+			}
 
 			Stream << QLatin1String("</CENTER>\r\n<BR><HR><BR><B><I>Created by <A HREF=\"https://www.leocad.org\">LeoCAD</A></I></B><BR></HTML>\r\n");
 		}
@@ -2198,7 +2238,12 @@ lcResult<void> Project::ExportHTML(const lcHTMLExportOptions& Options)
 				Stream << QString::fromLatin1("<IMG SRC=\"%1-%2.png\" ALT=\"Step %3\" WIDTH=%4 HEIGHT=%5><BR><BR>\r\n").arg(BaseName, StepString, StepString, QString::number(Options.StepImagesWidth), QString::number(Options.StepImagesHeight));
 
 				if (Options.PartsListStep)
-					AddPartsListImage(Stream, Model, Step, QString("%1-%2").arg(BaseName, StepString));
+				{
+					const lcResult<void> PartsImageSaved = AddPartsListImage(Stream, Model, Step, QString("%1-%2").arg(BaseName, StepString));
+
+					if (!PartsImageSaved)
+						return PartsImageSaved;
+				}
 
 				Stream << QLatin1String("</CENTER>\r\n<BR><HR><BR>");
 				if (Step != 1)
@@ -2227,7 +2272,10 @@ lcResult<void> Project::ExportHTML(const lcHTMLExportOptions& Options)
 
 				Stream << QString::fromLatin1("<HTML>\r\n<HEAD>\r\n<TITLE>Pieces used by %1</TITLE>\r\n</HEAD>\r\n<BR>\r\n<CENTER>\n").arg(PageTitle);
 
-				AddPartsListImage(Stream, Model, 0, BaseName);
+				const lcResult<void> PartsImageSaved = AddPartsListImage(Stream, Model, 0, BaseName);
+
+				if (!PartsImageSaved)
+					return PartsImageSaved;
 
 				Stream << QLatin1String("</CENTER>\r\n<BR><HR><BR>");
 				Stream << QString::fromLatin1("<A HREF=\"%1-%2.html\">Previous</A> ").arg(BaseName, QString("%1").arg(LastStep, 2, 10, QLatin1Char('0')));
@@ -2240,7 +2288,10 @@ lcResult<void> Project::ExportHTML(const lcHTMLExportOptions& Options)
 		}
 
 		QString StepImageBaseName = QFileInfo(Dir, BaseName + QLatin1String("-%1.png")).absoluteFilePath();
-		Model->SaveStepImages(StepImageBaseName, true, false, Options.StepImagesWidth, Options.StepImagesHeight, 1, LastStep);
+		const lcResult<void> ImagesSaved = Model->SaveStepImages(StepImageBaseName, true, false, Options.StepImagesWidth, Options.StepImagesHeight, 1, LastStep);
+
+		if (!ImagesSaved)
+			return ImagesSaved;
 	}
 
 	if (Models.size() > 1)
@@ -2298,7 +2349,12 @@ lcResult<void> Project::ExportPOVRay(const QString& FileName)
 	if (!Ready)
 		return Ready;
 
-	std::vector<lcModelPartsEntry> ModelParts = GetModelParts();
+	const lcResult<std::vector<lcModelPartsEntry>> ModelPartsResult = GetModelParts();
+
+	if (!ModelPartsResult)
+		return lcUnexpected(ModelPartsResult.error());
+
+	const std::vector<lcModelPartsEntry>& ModelParts = ModelPartsResult.value();
 
 	if (ModelParts.empty())
 		return lcUnexpected(tr("Nothing to export."));
@@ -2989,7 +3045,12 @@ lcResult<void> Project::ExportWavefront(const QString& FileName)
 	if (!Ready)
 		return Ready;
 
-	std::vector<lcModelPartsEntry> ModelParts = GetModelParts();
+	const lcResult<std::vector<lcModelPartsEntry>> ModelPartsResult = GetModelParts();
+
+	if (!ModelPartsResult)
+		return lcUnexpected(ModelPartsResult.error());
+
+	const std::vector<lcModelPartsEntry>& ModelParts = ModelPartsResult.value();
 
 	if (ModelParts.empty())
 		return lcUnexpected(tr("Nothing to export."));
@@ -3089,7 +3150,7 @@ lcResult<void> Project::ExportWavefront(const QString& FileName)
 	return lcResult<void>();
 }
 
-void Project::SaveImage(const lcImageDialogOptions& Options)
+lcResult<void> Project::SaveImage(const lcImageDialogOptions& Options)
 {
 	QString FilePath = Options.FilePath;
 	QString Extension = QFileInfo(FilePath).suffix();
@@ -3100,7 +3161,7 @@ void Project::SaveImage(const lcImageDialogOptions& Options)
 	if (Options.Start != Options.End)
 		FilePath = FilePath.insert(FilePath.length() - Extension.length() - 1, QLatin1String("%1"));
 
-	mActiveModel->SaveStepImages(FilePath, Options.Start != Options.End, false, Options.Width, Options.Height, Options.Start, Options.End);
+	return mActiveModel->SaveStepImages(FilePath, Options.Start != Options.End, false, Options.Width, Options.Height, Options.Start, Options.End);
 }
 
 void Project::UpdatePieceInfo(PieceInfo* Info) const

common/project.h

@@ -82,14 +82,14 @@ public:
 		return mIsPreview;
 	}
 
-	bool UsesStreamingMeshes() const
+	bool DefersModelMeshRequests() const
 	{
-		return mStreamMeshes;
+		return mDeferModelMeshRequests;
 	}
 
-	void SetStreamMeshes(bool StreamMeshes)
+	void SetDeferModelMeshRequests(bool Defer)
 	{
-		mStreamMeshes = StreamMeshes;
+		mDeferModelMeshRequests = Defer;
 	}
 
 	bool IsModified() const;
@@ -120,7 +120,7 @@ public:
 	bool ImportLDD(const QString& FileName);
 	bool ImportInventory(const std::vector<lcSetInventoryItem>& SetInventory, const QString& Name, const QString& Description);
 
-	void SaveImage(const lcImageDialogOptions& Options);
+	lcResult<void> SaveImage(const lcImageDialogOptions& Options);
 	std::vector<PieceInfo*> GetRequiredPieces() const;
 	lcResult<void> EnsureAssetsReady() const;
 	lcResult<void> ExportCurrentStep(const QString& FileName);
@@ -139,12 +139,12 @@ protected:
 	static bool CanShareMergePiece(const PieceInfo* Existing, const PieceInfo* Incoming);
 	QString GetExportFileName(const QString& FileName, const QString& DefaultExtension, const QString& DialogTitle, const QString& DialogFilter) const;
 
-	std::vector<lcModelPartsEntry> GetModelParts();
+	lcResult<std::vector<lcModelPartsEntry>> GetModelParts();
 	void SetFileName(const QString& FileName);
 
 	bool mIsPreview;
 	// External projects can parse their models before queuing direct meshes.
-	bool mStreamMeshes = false;
+	bool mDeferModelMeshRequests = false;
 	bool mModified;
 	QString mFileName;
 	QFileSystemWatcher mFileWatcher;