Visualization of Industrial Structures with Implicit GPU Primitives

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Visualization of Industrial Structures with
Implicit GPU Primitives

• Rodrigo de Toledo
• Bruno Levy

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Plan

• Motivation
• Previous work
• Our contributions
• New GPU primitives
• Implicit information on GPU
• Study-cases
• Results
• Conclusions

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Motivation

• Problem statement Interactive visualization of
  massive models is very difficult
• Too much primitives (triangles)
• Proposition Whenever it is possible, use
  implicit GPU primitives rather than triangles
• Example power plant

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Previous Work (1/3)

• Extended GPU primitives
• 2004, Extending the graphic pipeline with new
  GPU-accelerated primitives
• Quadrics

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GPU primitives

• Ray cast
• Z-buffer update
• Freely combined with triangle meshes
• Advantages
• Quality
• Computations by pixel
• Silhouette, phong etc
• Speed
• Very simple fragment shaders
• LOD behavior
• Memory
• Represented by few parameters

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Previous Work (2/3)

• ISVC 2007, Iterative Methods for Visualization
  of Implicit Surfaces on GPU
• Cubics and Quartics
• TORUS

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Multiple Tori

• GPU primitives are faster
• 16000 tori
• Newton at 50 fps
• the others lt 1fps

GeForce 7900
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Previous Work (3/3)

• TMCE 2008, Reverse Engineering for
  Industrial-Environment CAD Models
• Industrial environments are mainly composed by
  tubular structures (90)
• Topological approach

Quadrics
Torus
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Our contributions

• New GPU primitives
• Billboard cylinder
• Truncated cone
• Torus slice
• Implicit information encoded on GPU memory
• Floating-point texture
• Two study-cases
• Power-plant
• Oil platform

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Cylinders

• Billboard
• only 4 vertices
• tight projection enclosing the cylinder

perspective
orthographic
gl_RECT(-1,-1,1,1) or gl_RECT(-u,-v,u,v)
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Cylinders

• View-dependent coordinate system
• Computing perspective

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Cylinders

• Including caps on cylinders in perspective

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Cones

• Truncated and complete cones

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Torus slices

• Adaptive polyhedra
• Up to 180º
• Very useful for CAD

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Grouping primitive parameters

• Floating-point texture (each texel 4 scalars)
• Read by vertices
• Double speed
• Our biggest example only uses 10MB (340k
  primitives)

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Study cases

• Power plant
• 13M triangles

• Oil platform
• 27M triangles

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Reverse Engineering

• Results
• Memory reduction

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Speed-up (1/3)

• Test settings
• Without any culling
• They would disturb our results
• Surely, culling algorithms would increase all
  frame rates
• We have compared GPU primitives against triangles
• Triangles rendering
• Multiple VBO (Vertex Buffer Object)
• GPU primitives in two situations
• Exclusively
• Combined with unrecognized triangles
• GeForce 7900

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Speed-up (2/3)
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Speed-up (3/3)
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Image Quality
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Conclusion

• Topological reverse engineering shows good
  efficiency
• but it is restricted to CAD models (depends on
  regularity)
• With GPU primitives rendering we combine more
  quality, more speed and less memory
• Future work new implicit GPU primitives for CAD
  models
• GPU implementation Rev. Eng.
• Ex half-sphere, half-ellipsoid, sheared cylinder

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Thank you!

• For questions please email us
• Gmail rodrigodetoledo