Hello Robert, Am Freitag, 29. Februar 2008 schrieb Robert Osfield: > Hi Benjamin, > > Before heading off in any deep technical discussion I'd suggest answer > oneself a few questions. The aim is to find an easy route to solving > whatever problem you have, going the cluster route might be > worthwhile, but then it might not be needed at all. first of all thank you for your quick reply. In the following I will try to answer your questions. Feel free to ask again if my answers are not clear enough. > > What is your motivation for going the cluster route? First of all we have a cluster with 200 nodes that we can use and secondly it is a specification to our project. > > Have you explored multiple CPU/GPU set ups on a single machine? We have two CPUs but only one GPU on each node in the cluster. > > Have you fully explored scene graph/OpenGL optimization? I think you mean that we do not needed to use a cluster at all, because the scenes can be rendered on one computer. I think I can answer that with no. We are trying to create a parallel rendering algorithm and want to check how well it scales with the number of cluster nodes used. In the end it will hopefully be able to render really massive scenes (some hundred millions polygons) You can see it as some kind of research. So it is no option to only use a single big workstation. We do not want to use the rendering of OpenSceneGraph (or Chromium which was suggested in another e-mail) because we want to implement some algorithm ourselves to be able to handle these massive scenes (dynamical LOD with loose octrees for big models for example). When writing these rendering ourselves, we have more freedom in doing so.
Of course we could write the whole system without using OpenSceneGraph. But as stated before, it would be very nice to use some of its features on our central computer so we do not have to implement things like picking, dragging, culling and so on. We already began the implementation and now the question is, as stated in my first mail, how we can use the power of OpenSceneGraph on the front end to ease our lives. I have already used OSG in my Bachelor's thesis to implement adaptive animation algorithms and was very pleased by it's features. But I am not quite sure if the way I described in my first mail is the right one to follow. I do not know if it might be better to put the interface between this front end node and the rendering slaves somewhere else. So further hints are greatly appreciated. Regards, Benjamin > > Robert. > > On Fri, Feb 29, 2008 at 7:37 PM, Benjamin Eikel <[EMAIL PROTECTED]> wrote: > > Hello OpenSceneGraph community, > > > > we want to use OpenSceneGraph for a parallel rendering system. The scene > > graph should be located on a central computer which gets the user input, > > modifies the scene graph (with draggers) and displays the rendered image. > > The rendering should be done on other computers. We want to use a > > sort-last approach, where the geometry is distributed to these other > > computers and they send back an image with depth information that is > > composed on the central computer. > > My question is: How can I get the nodes which are determined visible > > after culling? I just want to know these nodes, so that I can get their > > vertex, color, ... data and send it together with the current model-view > > matrix via MPI to the other nodes. The other nodes should be able to > > render the objects and they should not need an own scene graph > > themselves. > > One solution I thought of is setting the DrawCallback on all Drawable > > nodes inside the scenegraph. I think this own DrawCallback can read out > > the vertex, color, ... arrays (for example if it is a Geometry node) and > > get the current model-view matrix for that node and send the data. > > Do you think this own DrawCallback is the right approach? > > > > Regards, > > Benjamin Eikel > > _______________________________________________ > > osg-users mailing list > > [email protected] > > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
