Scene objects organizing

I’d like to store bunch of objects in root scene without creating additional nodes. How can I utilize octtree or something similar for effective storing and searching among them?

Sure but you mix up some things here, the Spatials (Geometry and other Nodes) are what are in the Nodes. You cannot change that system, its for how the visuals work but you can reference your data in any form you like… If you don’t know how to do it up your java/programming skills.

You have to organize your scenegraph if you want something clear for your storing and searching system[]=scenegraph

There is no complete library for spatial indexing, is it? I should write my own world presentation and then map it objects to scene graph for visualizing, as I realized from the topic.

Let suppose objects are represented by cubes. What is the best data structure for arranging this cubes for fast collision checks, ray castings and for path-finding?

P.S. I’m just curios. What alpha-sorting algorithm is used in jmonkey in current release?

There is no “best” without any further information. A database is very good for storing and retrieving data…

Every object in scene may be represented via point, segment or parallelepiped with R radius envelope. Objects are dynamic and may be added or deleted from scene graph (not so frequently) and move permanently while game is going. There are also some rough triangle fragmented surfaces that are available for traversing. Surfaces are static and all necessary computations may be precalculated while loading. Objects may not intersect with each other and should use provided surfaces for calculating paths.

I need to cast rays from each object to another objects, find paths between them, position objects with respect to surface height.

Database is very inefficient, all data structures should reside directly in memory and be very tight linked to achieve good performance. I’m looking for O(logN) for ray casting. So I need to choose a data structure for efficient handling of described kind of scene information.

Just use bullet if its mostly about collision.

What situation is about alphablending sorting in jMonkey? I’ve read a long ago what this technique is required for rendering true transparent objects and quake and doom engine uses BSP tree for it. It still required for transparency, is it? Is there any alternative technique available? May be grown video memory limits have opened way for other techniques more cpu effective and memory consuming?