[vtkusers] vtkGlyph3D problem?

Tue Apr 13 08:46:26 EDT 2010

Sebastian,

I think it's basically related to available memory, but you'll just have to look in the VTK books or someplace like that for how exactly each type of data is stored, etc.

One thing for you to remember, too, for your arrows: If you have _that_ many arrows, it might not be helping people understand the data better, anyway, so you might want to start using vtkMaskPoints to only glyph a regular or random subset of your data:

http://www.vtk.org/doc/nightly/html/classvtkMaskPoints.html

Talk to you later,
-Eric

On Apr 13, 2010, at 7:58 AM, Sebastian Gatzka wrote:

> This option sounds really good.
> 
> How is the threshold of poinst I can display determined?
> If I can calculate this value from the available memory, I could make a switch and SetGlpyhTypeToVertex() instead of using arrows or spheres.
> 
> 
> 
> Am 13.04.2010 13:34, schrieb Eric E. Monson:
>> 
>> Hey Bill,
>> 
>> That is one situation where using the vtkGlyphSource2D with SetGlyphTypeToVertex() as the Source to your current vtkGlyph3D might work out well. Each vertex is really only one point, which is good for memory and for rendering speed. 
>> 
>> There is also some code in the ParaView repository for doing Point Sprites, but it's not something that's in the straight VTK collection.
>> 
>> If the memory problem is stemming from not just the number of points, but the number of scalars/vectors/tensors which are getting copied to each point, too, then it might be worth copying only the needed attributes to the data which will be glyphed with so many points.
>> 
>> Just as a side note, ParaView (www.paraview.org), which is built on top of VTK, works well for me when I'm trying to figure out how to build up my visualization. It doesn't have everything that's in VTK, but a lot of the parts are there, and it's a little easier sometimes to just play with combinations of representations to see what's possible or what looks good.
>> 
>> Talk to you later,
>> -Eric
>> 
>> 
>> On Apr 13, 2010, at 4:50 AM, Bill Chivas wrote:
>> 
>>> Hi Jerome,
>>> 
>>> good argument!
>>> I use glyph mechanism in order to represent the points on the grid. Can you think of other way to do that?
>>> Again, it seems to me impossible that there is no way with vtk to visualize the points and the grid at the same time!
>>> 
>>> Bill
>>> 
>>> 2010/4/13 Jérôme <jerome.velut at gmail.com>
>>> Hi,
>>> The "not able to allocate..." message is the usual one when you don't have enough memory.
>>> Don't forget that your sphere will be copied at each input point. Thus the final number of 
>>> points will be:
>>>    number_of_sphere_points * number_of_input_points
>>> 
>>> eg. 20x20 spheres = 400 points * 75k = 30M
>>> 
>>> each input point data is copied over each sphere point. It multiplies the amount of needed 
>>> memory as well (fo instance, a tensor multiplies by 9, if it's double data it is 4 octets 
>>> more, etc.)
>>> 
>>> HTH 
>>> Jerome
>>> 
>>> 
>>> 2010/4/13 Sebastian Gatzka <sebastian.gatzka at stud.tu-darmstadt.de>
>>> I'm experiencing the same problem!
>>> 
>>> Any ideas? Lack of memory?
>>> 
>>> Am 13.04.2010 10:27, schrieb Bill Chivas:
>>>> 
>>>> Hi all,
>>>> 
>>>> i use vtkGlyph3D with source a vtkSphereSource and input a vtkunstructuredgrid.
>>>> Grids with small number of vertices (approximately <10K ) are glyphed ok.
>>>> But large grids (e.g. vertices==75K) are not glyphed! A vtk message appears saying "not able to allocate...something" (i can't read the whole).
>>>> 
>>>> What is the problem? Large grids with many vertices can't be glyphed?
>>>> 
>>>> Bill
>>>> 
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>> 
>> 
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>> 
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> 
> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html
> 
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