[vtk-developers] Loading an External Graph to VTK

[David Gobbi]

I'm fairly certain that VertexData has nothing to do with the topology.

If you already have 3D coordinates for the nodes in your graph, I suspect
that what you need to do is set the Points along with adding all your
vertices and edges.

 - David


On Wed, Aug 12, 2015 at 4:22 PM, Saeed Mahdizadeh Bakhshmand <
saeedbakhshmand at gmail.com> wrote:

> Right, what I am looking for is like this:
> http://www.vtk.org/Wiki/VTK/Examples/Cxx/InfoVis/XGMLReader
> Here GML can load a full graph. But what I am looking for is to import
> topology of the graph.
> When I look into vtkGraphs that is what I see for VertexData and I assume
> modirying topology of the graph depends on these variables:
>
>  VertexData:
>
> Debug: Off
>
> Modified Time: 826248
>
> Reference Count: 1
>
> Registered Events: (none)
>
> Number Of Arrays: 0
>
> Number Of Components: 0
>
> Number Of Tuples: 0
>
> Copy Tuple Flags: ( 1 1 1 1 1 0 1 1 )
>
> Interpolate Flags: ( 1 1 1 1 1 0 0 1 )
>
> Pass Through Flags: ( 1 1 1 1 1 1 1 1 )
>
> Scalars: (none)
>
> Vectors: (none)
>
> Normals: (none)
>
> TCoords: (none)
>
> Tensors: (none)
>
> GlobalIds: (none)
>
> PedigreeIds: (none)
>
> EdgeFlag: (none)
>
>
>
> On Wed, Aug 12, 2015 at 6:01 PM, David Gobbi <david.gobbi at gmail.com>
> wrote:
>
>> On Wed, Aug 12, 2015 at 3:32 PM, Saeed Mahdizadeh Bakhshmand <
>> saeedbakhshmand at gmail.com> wrote:
>>
>>> Hello Experts,
>>>
>>> Is there a known way of loading a graph (3D node-link graph) that is
>>> defined and saved outside of VTK(position of vertices and adjacency matrix
>>> of the graph are stored in a text file e.g.) to be loaded to VTK and
>>> visualized?
>>> My guess is that GetEdgeData and GetVertexData are responsible for
>>> accepting vtk arrays, but not sure how those arrays can perfectly contain
>>> details of a graph and what happens if this graph is being imported from
>>> elsewhere?
>>>
>>
>> Let's back up a bit, because GetEdgeData() and GetVertexData() are not
>> the first methods to look at.
>>
>> A VTK data set is always considered to be made of these:
>>
>> 1) Geometry (points (or vertices/nodes), and connectivity between points)
>> 2) Attribute arrays (colors, scalars, etc. to associate with points,
>> edges, faces, etc).
>>
>> The GetEdgeData() and GetVertexData() method are for dealing with
>> attributes.  But from your question, it sounds like your main concern is
>> loading the geometry.  In other words, first you have to set the geometry
>> (the vertices, edges, and perhaps the points).  Only after that is done
>> should you worry about setting the attributes to go along with them.
>>
>> Unfortunately, I really don't know anything specific about dealing with
>> graphs in VTK, all I know is how VTK deals with data generically.
>>
>>  - David
>>
>>
>>
>>
>>
>>
>>
>
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