03/06/2008
Particle Rendering in ParaView
Attention
These slides are incomplete
and are provided for the IEEE Vis 08 DVD.
• The complete and full set of slides will be available from the CSCS web site under the following link
https://twiki.cscs.ch/twiki/bin/view/ParaViewMeshless/ParticleRendering
• And in the event of broken/changed link, from the ParaView3 Wikihttp://www.paraview.org/Wiki/ParaView
Representation/Display
• Standard Display panel• Surface/ Wireframe/ Points• Colour editor• Point Size• (Cube Axes)• (Interpolate)• Opacity
Color Editor (colour really)
Change Presets Define your own Load Save Scale Log/Lin Fit to data (See Track changes) Change Color Space
(interpolation between RGB values)
Manually edit scale
Point Sprite Representation
03/06/2008
Opacity control Track changes (max/min) 3 render modes Simple point
As before, but with opacity Sprite
A sphere, clearer contrast Shader
Radius controls
Opacity
Auto Min/Max changes with scalar
Enable disable auto change
Set min max manually Values <min mapped to 0, >max, to 1 Values from 0-1 mapped to
range according to opacity control setting
Can also change overall value with slider (<1)
Opacity
03/06/2008
Gaussian control Select peaks Drag left/right Drag up/down Scale/shrink
Great for volumetric datasets
Background color map for opacity
03/06/2008
When colour and opacity have same variable and same range
Not 100% accurate, but useful
Volume render effect
Volume animation (shown last year at spheric)
PointSize
• Change size according to taste• All particles the same• No perspective (well actually yes, but not accurate)• No relative scale between particles
• Try zooming in/out
• Point smoothing changes particles to rounded squares/ almost circles
• NB. Bug. If Point Sprite selected, then simple point selected, size clamped.
Depth Sort
• For transparency – particles must either be sorted back to front
• Cout = Csrc * Asrc + (1 - Asrc) * Cdst• Skip anything behind closest pixel• Colour correct
• Alpha can get messy when compositing images in parallel – distributed overlap/sort
TURN OFF DEPTH SORT FOR FASTER DISPLAY
Wrong Right
Depth Peeling
• Instead of sorting every object and drawing back to front• Draw everything once and save the image• Then draw it again, but only items in front of last one• Then do it again, and again in ‘peels’• Objects are not sorted, but each pass renders stuff in front, gradually
the final image is built up.• Not bad for brains/bones• Awful for lots of particles• Uses advanced shaders which mess up our renderer• Work in progress is getting depth peeling working with our renderer
Sprite mode
• Spheres are drawn with shaded edges• Improves contrast
Shader mode
• Better for smaller datasets• Where a parameter is to be highlighted
Ellipsoids : Quadrics : To be continued
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