[vtk-developers] GSoC 2015-CAD Model and Simulation Spline Visualization

[DEEVANKSHU GARG]

Hello all!
I have drafted my proposal for the project- CAD Model and simulation spline
visualization after discussions with Mr.David Thompson.Please review it and
suggest any edits or additions/subtractions so I can polish it before
finally submitting it.
Here's the link-
https://docs.google.com/document/d/1WvVhjcitFqeehpCBOHk_N71pPY2BV1UX9gbvhehL6pA/edit?usp=sharing



On Wed, Mar 25, 2015 at 9:58 AM, David Thompson <david.thompson at kitware.com>
wrote:

> Hi Deevankshu,
>
> > Sorry for that little break in between but I was really stuck in my
> mid-semester exams.
>
> That's OK; I am also in a time crunch to finish a paper.
>
> > .... Basically, it would be up to the IGA solver to provide us with
> Bezier patches.The data provided from the patches about the control points
> and vertices of the curve will be stored in arrays using the
> {vtkAbstractArray ,vtkDataArray,vtkDoubleArray} classes. ...
>
> Correct, although if you are interested in storing BSplines (and then
> converting to Bézier patches on demand), it would be better to store the
> control points in a vtkStructuredGrid.
>
> > Then the main work starts.These datsets will be processed by further
> filters present in the new mesh rendering class.
>
> Yes. Filters would likely inherit vtkMultiBlockDataSetAlgorithm.
>
> > The main tasks in our hand are-interpolation,point inversion and
> finally,tesselation and rendering.Here's a rough implementation of the
> methods used to perform these tasks. ...
> >
> > Tesselation and Rendering-
> > I have always loathed the necessity of flow charts.I am attaching one
> here too explaining the implementation of the tesselation method.A brief
> explanation about this-
> > -Tesselation Control Shader-Determines how much to tesselate,per-vertex
> attributes,new patch vertices in xyz.
> > -Tesselation primitive generator-Tessellates the curve or surface into
> uvw coordinates.
> > -Tesselation evaluation shader-Evaluate the curve or surface. Possibly
> apply a displacement map.
> > After tesselation,finally rendering takes place which involves writing
> interpolated values out at the nodes of the
> simplices(lines,triangles,tetrahedra).
>
> While it would be nice to have direct OpenGL rendering of patches, I would
> prefer to implement tessellation on the CPU first so that the resulting
> tessellation can be represented as a VTK dataset and used in further
> operations before rendering. Also, since IGA frequently involves
> 3-dimensional volumetric elements, rendering using the flowchart you show
> would mean writing a volume renderer (which is an ambitious task and could
> be its own GSoC project). If we tessellate on the CPU then VTK already has
> volume rendering code that can be applied to the tetrahedra that
> approximate a volumetric patch.
>
> > For the cutting part,I still have to see what changes will have to be
> made to the already existing code.I will get to that soon.
> >
> > Please tell me what you think about it.Would it be a good idea to divide
> the whole timeline into these three parts or do you recommend something
> else?
>
>
> I think 3 sections would be fine for the timeline. I would prefer to work
> by (1) negotiating header files and unit tests, then (2) implementing the
> classes for each of the 3 sections.
>
>         David
>
>
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