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Questions tagged [octree]

An octree is a tree data structure in which each node has eight child nodes. A major application of octrees is in 3d graphics as they are the primary structure used for storing voxel (volumetric pixel) data.

Wikipedia: "An octree is a tree data structure in which each internal node has exactly eight children. Octrees are most often used to partition a three dimensional space by recursively subdividing it into eight octants. Octrees are the three-dimensional analog of quadtrees."

Relevant topics include voxels and color quantization.
For more information see http://en.wikipedia.org/wiki/Octree

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Generalized (non-slicing) pointer to templated tree nodes? (C++)

I'm working on an octree implementation where the tree nodes are templated with their dimensional length (as a power of 2): template struct node_t { enum { DIM = 1 << N }; node_t * parent; node_t * children[8]; long…
ben_reilly
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Voxelization of a Scene with Instanced Objects

I have created a simple scene in directx11 that has a plane as a floor, with several spheres, cubes and rectangular walls. There is only 3 objects loaded: a plane, cube and sphere; but the cube and sphere are instanced several times with different…
gboxentertainment
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Get image top 10 colors

I am generating color pallete for image through octree quantization. Its gives me maximum 256 colors for any image. Now i want to show only top 10 ( according to the quantity of color in image ) colors of the image out of these 256 colors. How can i…
Tom Rider
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How to use a quad/oct tree for a block world

I have been messing around with octrees and quadtrees for the past couple of days. I can build them, iterate them, and spit out information that I need. I also know they are very useful in collision detection, where you take the screen and…
User
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Barnes Hut worst case memory scenario

I want to run a Barnes Hut N-body simulation (Wikipedia article). I know how much memory a single node of the octree will occupy, but I can't figure out what a worst case memory usage scenario would be for a given number of particles. In short, I'm…
Void Star
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Different behaviour between opencl c99 and c++ with the same implementation of a realtime voxel raycaster

I am working with opencl to develop a voxel raycasting engine. I am trying to do something similar to Gigavoxels by Crassin. In this paper, they are using an octree to store the voxel data. For the moment I am just trying to descend inside the…
valeriodidonato
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Performance of positioning voxels in an octree/quadtree

This is something I've been thinking about for the past couple hours. This is a mind exercise. So I learned what octrees were today! Very interesting! I've been thinking through how to implement an octree that resolved to a voxel. My biggest issue…
Nathan Goings
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Concerning Octrees

I am creating a Minecraft like terrain engine thing, and I was wondering what exactly octrees are. With my engine I have seperated each part of it into chunks or regions - which from what I have read has something to do with it. Also, I was…
Darestium
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Implementation of octree system

I have been trying for some time to implement an octree system in a class project aimed at 3D image rendering optimization. But I always block in the implementation of this one, indeed I have a basic class center that I must adapt to an octree…
Lvs17
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Get the tighest bounding box

I think the code is self explanatory: // Set the bbox min and max of the lower node current_min_bound = lower_get_bbox_min(buf, lower_handle); current_max_bound = lower_get_bbox_max(buf, lower_handle); // Set lower node bbox if(current_min_bound.x…
Jaime Sierra
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Collision detection with octrees realized with python-fcl

I want to finish the collision detection with point cloud represented by Octrees. With the python-fcl lib, I tried the following code snippet by myself x = np.random.random([5, 3]) y = np.random.random([5, 3]) object1 =…
KKKmelody
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Raytracing octree gets wrong intersection with negative directions

I'm trying to implement a GPU raytracer that traverses an octree given it's AABB. I'm using "An Efficient Parametric Algorithm for Octree Traversal" as my basis for this project. During the implementation, I found some problems with negative…
Diego Saragoza Da Silva
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How to properly declare a class member pointer to an array without allocating array

I am new to C++ and trying to create my first Octree structure. Common way to store children is simply to store 8 pointers in each node. like so: class Octant { Octant *child0; Octant *child1; Octant *child2; //... } This means each…
Pasha Ho
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PCL GPU Octree implementation is slow

I want to use pcl::gpu::Octree for storing the obstacle map and retrieving the closest distance to a given point. I've modified an official test example as follows: int main(int argc, char** argv){ using namespace pcl::gpu; …
GPrathap
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Printing an element from an octree with cout alters the content?

I tried creating an octree in c++. Seems to work fairly well, but when I print the content of the tree it returns an access violation error. Running this in debug will print two different numbers, although the content should not have been changed.…
Thomas Conrad
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