Questions tagged [octree]

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Implicit Functions and extracting an isosurface

I recently discovered a paper on Dual Marching Cubes which produces a much reduced poly count to other methods like Dual Contouring and Marching Cubes, however a recurring theme when reading these ...
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1answer
653 views

Octree subdivision problem

Im creating octree manually and want function for effectively divide all nodes and their subnodes - For example - I press button and subnodes divided - press again - all subnodes divided again. Must ...
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0answers
27 views

How to track/identify amorphous blobs in 2D or 3D space

In doing HTML/DOM work, you are working with concrete nodes which you can visibly touch and have a defined shape and boundary. What I'm wondering though is like with a cloud like structure, or like a ...
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51 views

How can I save a local player modification into a procedurally generated terrain density octree?

So I have recently been researching how to implement DC for procedural terrain. I originally planned to use a 3D grid that just stated if the point is solid or not. I have noticed that most other ...
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2answers
177 views

Need help with simple octree implementation

Hello I'm trying to implement an octree, but when I query the centre positions they all return zero, but these should be offset from zero. Here is my code: ...
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0answers
59 views

Modern way of getting points within a distance?

I'm making a game engine, and some components may want to interact with others based on distance. Currently, the component registers an update listener which runs on a loop, then it checks the ...
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1answer
1k views

Building an Octree for terrain generation

I've previously implemented marching cubes/tetrahedra to render an IsoSurface. It worked (YouTube), but the performance was dire as I never got around to implementing variable Level of Detail based on ...
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0answers
290 views

Simple Stupid Funnel Algorithm (SSFA) for 3D Navigation

tl;dr I need an algorithm similar to SSFA except for portals with 4 vertices (or n vertices if an algorithm like that exists). I'm working on a game that requires pathfinding in 3 dimensions. By this ...
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2answers
606 views

How can I calculate an octree node's depth from its location code?

The article Advanced Octrees 2: node representations states: The AABB (axis-aligned bounding box) of the node can be stored explicitly as before, or it can be computed from the node’s tree depth ...
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0answers
29 views

Calling update oct-function (only if changed)

Issue: How is the best way to update my units position on the oct-tree, I'm struggling with the logic, specifically when It changes oct, tree, I want it to pop itself of its previous oct-tree, and it ...
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1answer
120 views

Setting up an “Oct-Tree”

Instead of spam the same hard question like my previous one that Is difficult to get a minimum verifiable example for, I have decided to rework my path-finding and I can fix a lot of my issues with an ...
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1answer
558 views

How can I store point voxel terrain in octrees

I am writing a voxel engine in LWJGL3 - binding for OpenGL 4 for JVM. Recently I implemented an octree storage of cubic voxels. In my implementation each leaf node of an octree has one voxel, voxels ...
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1k views

How do I implement a sparse voxel octree?

I've been working on a voxel engine and I want to implement sparse voxel storage. As I understand it, it works a bit differently from a regular octree and has some neat performance increasing "tricks"....
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0answers
204 views

How do I test my Octree implementation?

I decided to use an Octree subdivision in my game. After implementing it, I do some research (a few tests and comparisons) and came up with several questions about. The main question: How to test my ...
4
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1answer
466 views

Determine wheter an octree node needs to be continue

For collision detection (moving vs. non-moving) in my current project, I decided to implement an octree approach after the preselection. The only collision detection I'm currently using is a AABB-vs.-...
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0answers
245 views

How to convert an octree to a 3D array

I have an octree that I'm planning to use for 3D pathfinding. My plan was to break down the world such that all the leaf nodes of the tree would be of equal dimensions that would create a nice grid ...
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2answers
152 views

Drawbacks to an Octree and Quadtree hybrid?

I've implemented an octree to divide 3D space that contains several objects. I've noticed in certain octree nodes I could use more refinement in some axis, but splitting the node into 8 children is a ...
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0answers
571 views

Does anyone have a example of Dual Contouring in C#?

I'm trying to develop a method of creating terrain using Perlin. I've followed plenty of the Minecraft tutorials, and got them to function. I've done some playing around with MarchingSquares, but I'm ...
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1answer
833 views

General Octree question: What do you actually store?

Ok, So I'm experimenting with various terrain generation methods, primarily in Unity, but i'll admit to not use all its features because I started learning about Game Dev in XNA YEARS ago. So, I made ...
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2answers
4k views

Octrees as data structure

In my cube world, I want to use octrees to represent my chunks of 20x20x20 cubes for frustum and occlusion culling. I understand how octrees work, I just dont know if I'm going about this the right ...
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1answer
762 views

How can I correctly instantiate an octree in UE4?

I tried to create a simple Octree like this: (I looked at the FMeshTriOctree source code since no question in answers.unrealengine.com helped me) ...
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1answer
317 views

Simplyfing/dissolving octree to simple boxes by adjacent octants with similar traits

I am looking forward to create a navigation volume to be utilized by AI actors. The approach I am trying to tackle here is to first generate an octree and associate with respectable flags/data (type, ...
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1answer
1k views

Is Frustum culling still needed today?

I'm reading about efficient Frustum culling algorithms. I found an article about a smart method that first use the Frustum AABB (Axis Aligned Bounding Box) to eliminate most of the scene before check ...
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350 views

Octree Frustrum Culling

times came when i had to implement some culling into my engine. I started by reading some stuff and so far so good. I managed to create an octree which can effectivly divide my geometry's vertices (...
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0answers
599 views

How to convert an octree to a polygon mesh?

So if I have dynamic voxel terrain data stored in an octree representation what would be the best way to go about converting the octree to a polygon mesh which I can render with OpenGL? A lot of ...
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0answers
46 views

How to move octree data correctly from parent to child?

This is my first question, so apologies if it is a repeat, I have had a look at the other questions and I still can't seem to find an answer to this. So I am making a recursive octree in OpenGL. So ...
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1answer
6k views

How to efficiently render a large terrain mesh?

Recently I've been stuck on a problem thinking about the best way to generate a terrain into my game. In another projects I normally used heightmaps, so all the core-work was based on the engine used, ...
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1answer
1k views

Should I use octree or quadtree for my spacial data structures? [closed]

I would like to know the advantages and disadvantages of using octree or quadtree for spacial data structures? In a 3d gaming setting would you ever need more than 4 children nodes? Does it take ...
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0answers
1k views

Binary Space Partitioning of 3d Triangle Mesh (for finding nearest points)

I'm writing a Binary Space Partitioning (BSP) tree for the purpose of optimizing finding the nearest point on the surface of a 3d triangle mesh with respect to another point. I'm currently following a ...
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1answer
214 views

How can I split up a large model into an octree codewise?

For collision detection, I am attempting to split up a large model into an octree. If we take this black thing thing to be the ship (104,000 vertices): Then I would like to split up the faces I ...
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0answers
516 views

Actual use of sparse voxel octrees in a game engine

Looking for different ways to speed up my simple voxel system reducing the number of voxels and generated triangles, I stumbled upon these sparse voxel octrees. Now, I read a lot about it: how do they ...
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1answer
447 views

Frustum culling with an octree: one AABB per bone or one AABB per object?

I've constructed an octree for use in frustum culling. The question is, should I insert an AABB for each bone of each object, or just the one AABB for the object?
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1answer
466 views

Dynamic Quad/Oct Trees

I've recently discovered the power of Quadtrees and Octrees and their role in culling/LOD applications, however I've been pondering on the implementations for a Dynamic Quad/Oct Tree. Such tree would ...
3
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1answer
2k views

Marching cubes over an octree dual - how?

In Dual Marching Cubes the dual of an octree is tessellated via the standard marching cubes method. But the classical marching cubes algorithm operates only on cubes with eight vertices (it uses signs ...
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4answers
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What library for octrees or kd-trees? [closed]

Are there any robust performant libraries for indexing objects? Objects would have bounds themselves, rather than being represented by points; and an object could therefore be in more than one ...
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1answer
130 views

How to create more vertexes from within a shader in OpenGL?

when rendering voxels in octrees, the only information necessary is the current octree-level, -position and colour/texture. But one has to send eight vertices to the rendering pipeline in order to ...
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0answers
340 views

Overlap detection, nearest neighbors

I'm trying to get something similar to the Nearest Neightbor Problem, except I only want neighbors with radius overlapping a radius, and all of them. I'll explain my problem before explaining what I ...
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2answers
6k views

When would you use an octree in a voxel Engine?

I've been reading about Octrees, and I understand how they work (or at least I think I do). However, I can't figure out why you would use octrees instead of a simple multidimensional array. In my ...
2
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1answer
306 views

About Octrees Usage

I'm studying about Octrees since I've read they're used to organize my elements in space, but I couldn't find any practical example so I'm kinda lost as to their use. From what I could understand, I'...
4
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1answer
845 views

Raycasting problem

I have a problem with my raycasting. I have 8 cubes, that define the first level of an octree (Eg. they create bigger cube). I need to raycast them and "render" each cube. If I have only one cube, ...
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3answers
3k views

Scene graphs and spatial partitioning structures: What do you really need?

I've been fiddling with 2D games for awhile and I'm trying to go into 3D game development. I thought I should get my basics right first. From what I read scene graphs hold your game objects/entities ...
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4answers
2k views

create terrain with some vertical cliffs, natural arcades, caves using octree

I am about to start creating the first terrain. I would like to create a terrain with vertical cliffs, natural arcades and caves. For instance in one point the terrain might look like this. I want ...
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3answers
3k views

How to draw only visible tiles?

I have a big map with isometric tiles(3d camera), how can i draw only visible tiles ? Whats the best way to do that ? space partitionning (octrees etc...)?
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1answer
650 views

Handling polygons in multiple nodes of an Octree

I'm building a 3d software renderer for grins to learn the math and rendering concepts. I've implemented the basic drawing of polygons with some basic optimizations like back face culling and frustum ...
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1answer
2k views

Octrees and Vertex Buffer Objects

As many others I want to code a game with a voxel based terrain. The data is represented by voxels which are rendered using triangles. I head of two different approaches and want to combine them. ...
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1answer
2k views

Octree implementation for fustrum culling

I'm learning modern (>=3.1) OpenGL by coding a 3D turn based strategy game, using C++. The maps are composed of 100x90 3D hexagon tiles that range from 50 to 600 tris (20 different types) + any ...
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1answer
5k views

Would someone please explain Octree Collisions to me?

I've been reading everything I can find on the subject and I feel like the pieces are just about to fall into place, but I just can't quite get it. I'm making a space game, where collisions will ...
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2answers
2k views

Sparse Voxel Octrees which parts on GPU or CPU?

I'm currently doing research into building my own voxel engine and found a lot of articles mentioning SVOs as the best mechanism. I just wanted to know that I understood the algorithm correctly, ...
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1answer
1k views

Octree division

I have an octree, with a high poly rabbit inside it, and a 12 polygon platform. The deal is this. You're shooting a ray at the rabbit. He of course dodges (or you miss). The yellow beam is your ...
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2answers
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What's the state of the art in Space Partitioning for games? [closed]

I know about BSP trees, Octrees and Portal that where used for a long time. But modern games still use this systems or they are using new things? If it's possible with pros and cons, considering ...