Questions tagged [octree]
The octree tag has no usage guidance.
70
questions
1
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0answers
81 views
How to use transvoxel cell cache with octree structure?
I have been implementing Transvoxel in to my Marching Cubes project in c++. The Transvoxel documentation and available code examples feature cell vertex reuse (caching) via indices. The main benefits ...
2
votes
3answers
633 views
How to read a sparse Octree sequentially, like a 3D array?
Is it possible to read a sparse Octree like a regular 3D grid:
for(z)
for(y)
for(x)
...and still benefit from skipping large empty areas?
I need this for a ...
0
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0answers
22 views
Can inserting/removing one point in a quadtree or octree cause multiple splits/collapses?
I was reading Robert Nystrom's Game Programming Patterns website and, in the section about spatial partitioning, particularly in the section on quadtrees, he mentions:
Objects can be added ...
0
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0answers
46 views
How to calculate ray unit grid intersections?
P is ray origin, D direction. How do I calculate tx, ty(s)? This is for octree raycast. The primary goal is to get 1st intersection voxel (v) then second (v") and so on.
0
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0answers
38 views
How to raycast octree for closest leaf node?
So I need to raycast a octree for closest leaf node as efficient as possible. I will be doing it on compute shader (hlsl), but I think it doesn't matter because first I need to understand the approach ...
0
votes
1answer
59 views
How to construct a octree density from SDF for MC
It very clear how it works with a regular grid. 3 inner loops - x, y, z over some size. The smaller the cells, so will be the mesh more detailed.
But how about octree. I know i can stich different ...
0
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0answers
18 views
Nearest Vector3 to Vector3 from last frame
Suppose you have a Vector3 provider of pointcloud positions that update every frame - call it Nullable<NativeSlice<Vector3>> pointClouds
Say you want to ...
0
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0answers
67 views
Octree LOD without traversing the entire tree
I am working on a voxel engine that uses a huge Hashed Linear Octree that reconfigures when you move. Each octree leaf is a voxel. The world is procedurally generated using 2D Perlin noise.
The octree ...
0
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1answer
62 views
Octree Terrain Destruction and LODs
Meet my octree world:
My end goal is to have this world destructible, and I am having an issue warping my head around how this can be done when you have LOD. The basic principle of LOD (as I ...
0
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0answers
85 views
Benefit of storing chunks as Octree leafs vs single block as Octree leaf
I saw many voxel game developers opt for a strategy that involves using an octree whose leaf nodes include a 16x16x16 (or 32^3 or 64^3) chunk instead of having leafs represent a single voxel.
What is ...
1
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0answers
38 views
Fast Occlusion Discovery in 3D Point Cloud
I am trying to find occluded objects given a view point at x,y,z in the scene. For instance in the example below all the points constructing trees should be ...
0
votes
1answer
514 views
Using octrees as LOD system
I am using an octree to define my 3D voxel world.
And I want to use octree subdivision as a LoD system.
This means, subdivide close to the player, but far away nodes un-subdivided.
But it occurs to me ...
0
votes
0answers
115 views
Too many neighbors when pathfinding in Sparse Voxel Octree
Imagine we have upto 9 or so layers (that is depth), and due to some big colliding platform in the level, one of the empty nodes close to the root have all much smaller nodes as neighbors at one of ...
0
votes
0answers
30 views
Best option to narrow a known set of triangles?
I am building collision detection and response in a custom engine. This routine happens between the moving player, and static entities on the map.
In the first phase, the broad phase I am moving the ...
1
vote
0answers
29 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 ...
1
vote
0answers
65 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 ...
1
vote
0answers
62 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 ...
0
votes
2answers
201 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:
...
1
vote
0answers
30 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 ...
1
vote
1answer
131 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 ...
1
vote
0answers
399 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 ...
4
votes
0answers
249 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 ...
1
vote
0answers
337 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 ...
1
vote
0answers
764 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 ...
3
votes
1answer
1k 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 ...
0
votes
2answers
264 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 ...
0
votes
1answer
1k 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)
...
2
votes
1answer
383 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, ...
9
votes
1answer
2k 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 ...
5
votes
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 ...
3
votes
2answers
915 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 ...
0
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0answers
496 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 (...
2
votes
0answers
2k 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"....
4
votes
0answers
684 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 ...
1
vote
1answer
721 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 ...
1
vote
0answers
50 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 ...
0
votes
1answer
2k 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 ...
2
votes
0answers
2k 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 ...
0
votes
1answer
257 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 ...
2
votes
0answers
602 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 ...
0
votes
2answers
1k views
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 ...
3
votes
1answer
3k 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 ...
4
votes
1answer
531 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.-...
3
votes
1answer
545 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 ...
10
votes
1answer
7k 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, ...
1
vote
1answer
143 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 ...
1
vote
0answers
354 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 ...
5
votes
2answers
8k 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
votes
2answers
5k 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 ...
2
votes
1answer
388 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'...
