[osg-users] Point Cloud

[jago jagoc]

Dear All,

i am trying to visualize a point cloud with Openscenegraph,there are about 1 707 708 points but it should be more,there are some problem when i zoom in or out, some hole appear on the cloud. You can see the effect in the picture ZoomIn.jpg in the other the normal view.

I load the points from file and put toghether in a Geode

...

osg::Geometry* pointsGeom =

new osg::Geometry();

osg::Vec3Array* verticesFromFile =

new osg::Vec3Array;

verticesFromFile->push_back(osg::Vec3(x,y,z));

pointsGeom->setVertexArray(verticesFromFile);

geode->addDrawable(pointsGeom);

Any suggestion?

Another question is how can organize the data to improve performance? Can  i use some osgUtil special algoritm?

I am using:

Graphics card : nvidia Quadro Fx 3600M

Driver version: 7.15.11.6755

Openscenegraph 2.8.0 VC8

 

Best Regards

 

 

[Robert Osfield]

Hi Jago? Jagoc? Could you please sign with your first name so we
know how to address you correctly, thanks,

On Tue, May 19, 2009 at 9:43 AM, jago jagoc <jag...@gmail.com> wrote:
> Dear All,
> i am trying to visualize a point cloud with Openscenegraph,there are about 1
> 707 708 points but it should be more,there are some problem when i zoom in
> or out, some hole appear on the cloud. You can see the effect in the picture
> ZoomIn.jpg in the other the normal view.
> I load the points from file and put toghether in a Geode

The way I've done large point clouds (10 million points +) is to use
VBO's and segmentation of the geometry so the points are stored in a
series of osg::Geometry each of which have a 10,000 vertices in them.
The 3dc plugin does this so have a look at how it's implemented.

The need to chunking up the geometry like this is that graphics
cards/OpenGL drivers work when you give them data is blocks that they
get easily download asynchronously and store locally on the graphics
card when required.

I can't explain the holes, sounds like a driver bug. Try the above it
might well just solve the problem.

Robert.
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[jago jagoc]

Dear Robert,
Your suggestion has been very useful to me, i have now 60 fps with the
same point cloud. For the hole i am trying to test the driver above.
Thank you.
 Best regards,
Jagovic