What

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Whats New in ParaView

• John Greenfield
• Under contract to
• Sandia National Laboratories

Sandia is a multiprogram laboratory operated by
Sandia Corporation, a Lockheed Martin
Company,for the United States Department of
Energy under contract DE-AC04-94AL85000.
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Background
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Deploy Research to Production

• Use the Visual ToolKit (VTK) as a framework
• Only replace small parts of the framework with
  our research codes the rest is tried, tested and
  supported by a whole community.

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Sandia Vis RD with ParaView / VTK

• ParaView is an open-source visualization toolkit
  
• Based on the VTK (Visualization ToolKit)
• Sandia Vis RD is the most significant outside
  technical contributor
• Core algorithms that enable vastly improved
  parallel performance.
• Volume rendering (synthetic x-rays of simulation
  results)
• Image delivery to the desktop.
• Driving 60 mega-pixel display walls.
• Able to interactively explore Sandias largest
  simulation data sets (gt 70 million finite
  elements).
• ParaView stats
• ParaView 30 downloads / day around the world.
• VTK (Visualization ToolKit) is used by over
  25,000 people worldwide.

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Sandia Production
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Sandia ParaView Production Environment

• Average 25 users per month
• 47 different users in 2QFY05
• Scripts for easy use on clusters
• Allows use of data in place without moving it.
• Allows easy parallel rendering for performance.
• Available on Linux, Windows, SGI, Mac OSX.

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Current Sandia Additions
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Performance

• New Way
• Directly Load 1900 exodus files 45 seconds
• Clip data 20 seconds
• No copying or moving the data at all
• Runtime Vis Analysts can look at data as soon
  as the restart files hit the disk
• Old Way
• Copy/convert data into proper format (hours)
• New way Convert using RD software (minutes)
• Load converted data 7 minutes
• Clip data 4 minutes

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D3 Load Balancing and Data Distribution

• Load balancing
• Data distribution
• Multi-file Cleanup
• Ghost cell computation!

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ICE-T Parallel Rendering

• Good load balancing characteristics
• Excellent Scalability (1.5 Billion tri/sec in
  2005)
• Supports both Desktop Delivery and Tiled Displays
• ICE-T is now the default for all parallel
  rendering in ParaView (faster/better than
  Kitwares alternatives)
• 20 fps at the Desktop (reduced image res during
  interaction, full at stop)

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Movie
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Performance Results

• Aggregate rate of over 1.5 billion polygons per
  second.
• 128 Processor Cluster running servers
• Desktop client connected at 100 Mbps
• Visualizing one of the worlds largest polygonal
  datasets, a 473 million triangle isosurface
  generated from a Richtmyer-Meshkov simulation run
  at LLNL (LLNL UCRL-MI-151066).

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Higher Order Elements

• Correct

• Typical approximation

• Rendering Higher Order Finite Element Surfaces
  in Hardware, Proceedings of GRAPHITE, Melbourne
  Australia, February 2003.

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Quadratic Elements

• Old Way Hex-20 (incorrect)

• New Way Hex-20 (correct)

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VTK Chromium
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Along the Way

• Generic tetrahedral refinement algorithm
  available in ParaView now for tri-quadratic
  elements.
• Mesh quality filter now in ParaView (for
  benchmarking our refinement algorithm, but may
  also be useful to meshing community).

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Unstructured Volume Rendering
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CTH AMR (Brand New!)
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Lookmarks
What? Quick and easy way to switch
between views
Why? -Time Savings -Collaboration -Comparison -
Organization
How? Bookmarking tool that Adds, Removes,
Updates, Organizes, Imports, and Saves Lookmarks
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• Why?
• Time Savings
• Collaboration
• Comparison
• Organization

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Sandia's current contributions to ParaView

• Work on the image delivery system.
• Lookmarks Visual Bookmarks
• D3 Load balancing and data distribution.
• IceT parallel rendering.
• Higher order elements Adaptive sampling of
  quadratic elements
• Unstructured Volume Rendering.
• Mesh Quality Measures
• Exodus Reader and Writer
• CTHAMR Reader

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Sandia's current contributions to VTK

• VTK OpenGL extension manager
• vtkPainter
• vtkParallelRenderManager
• ICE-T
• Volume rendering
• vtkMemoryCoherenceFilter
• vtkOptimizer
• vtkFixTetrahedra
• vtkGradientFilter

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Sandia's current contributions to VTK (cont.)

• vtkInteractorStyleRubberBandZoom2
• vtkItsReader/Writer Reads/writes files in its
  format.
• vtkTrisReader/Writer Reads/writes files in .tris
  format.
• vtkPerturbPoints
• A technique for subdividing tetrahedra,
  triangles, and lines such that any coincident
  edges or faces are always subdivided the same
  way.
• A filter that converts quadratic finite elements
  into a collection of linear finite elements
  adaptively

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Sandia's current contributions to VTK (cont.)

• Higher Order Elements
• A programming interface (developed jointly with
  Kitware) to allow "read-only" access to higher
  order finite elements
• Code for representing higher order (quadratic and
  higher) finite elements in a more generic and
  extensible way
• Readers and writers for storing/retrieving the
  above meshes to/from disk in an XML file format.
• Techniques for visualizing the above meshes using
  isosurfaces and deformed, colored boundary
  surfaces.
• A parallel rendering infrastructure in vtk to
  support Chromium.
• A utility for performing automated tests of
  visualization code based on VTK's techniques

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Sandia's current contributions to VTK (cont.)

• File writer that is capable of writing out
  EnSight Gold files.
• Added functionality to the Exodus reader that
  allows it to parse a Material/Part/Assembly XML
  metadata file and organize blocks within ParaView
  based on that information.
• Bug-fixes to a Delaunay triangulation routine to
  correct invalid mesh output

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Future Sandia Additions
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Future additions

• Improved interface to plotting
• Parallel volume rendering
• Shading
• Targeted interfaces
• Side-by-side views Real and phase space.
• Oculus volume rendering application

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Parallel Volume Rendering in ParaView

• D3 (already in ParaView) can, in parallel, divide
  a data set by a K-D tree.
• Visibility sorting of a K-D tree is simple.
• ICE-T (already in ParaView) has the capability of
  compositing images in order.
• So our approach to parallel volume rendering is
  to divide the data by a K-D tree and use the tree
  to order the ICE-T compositing.

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Perceptual Clues (upcoming)

• Shadows

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Perceptual Clues (upcoming)

• Old way Some random colors

• New way Could use meta data to show realistic
  material properties

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Next Directions

• Unique functionality and performance is good
• One size fits all user interface with 10000
  buttons is not
• Put targeted interfaces on top of all the vis
  code we already have.

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Prism

• Link simulation geometry view with multiple phase
  space views to promote understanding of the
  physics

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Oculus

• Oculus is a volume rendering application with a
  focus on generating images that are comparable to
  those made in high energy density physics (HEDP)
  experiments.

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VtkHardwareShader Cg, GLSL, etc.

• Materials assigned per-vtkActor through
  vtkProperty
• End-user (ParaView) assigns Materials to objects
  in the scene
• VTK-based applications coordinate vtkActors and
  Materials
• XML Material file
• Describes a shader and it's interface to VTK
  (types, values, etc.)
• Values for vtkProperty data members
• Al 2040, Brushed Al 2040,1040 Steel, etc.
• VtkPainters will access all Vertex Attributes
  (VTK only sets 4!)
• Extend vtkDataSetAttributes to flag attributes
  for hardware
• VtkDataSetAttributesSetVertexAttrib0...N(...)

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VtkHardwareShader and Decorator
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VtkHardwareShaderProperty vtkSNL Prototype
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vtkPainters

• vtkPainters are a replacement for
  vtkPolyDataMapper.
• vtkPolyDataMapper is monolithic.
• Obfuscated code.
• Hard to extend.
• Not ready for use with shaders.
• A vtkPainter is just a piece of the rendering
  process.
• Painters are chained together to form
  functionality of a mapper.

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vtkPainters
vtkMapScalarsPainter
vtkOpenGLClipPlanesPainter
vtkOpenGLLightingPainter
vtkOpenGLPolyDataMapper
vtkOpenGLWireframePainter
vtkOpenGLDisplayListPainter
vtkVertexArrayPainter
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vtkPainterDeviceAdapter

• Painters do not (necessarily) make direct OpenGL
  calls.
• They use a vtkPainterDeviceAdapter.
• The vtkPainterDeviceAdapter provides an abstract
  interface for pushing attributes (i.e. vertex
  positions, colors, etc.).
• Easy to swap the standard vtkPainterDeviceAdapter
  with one that sends to Cg or Sh or HLSL or
  whatever.

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• END