# Tagged Questions

Collision detection is the determination of whether or not two or more entities make contact with each other during gameplay.

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### Matching collider to character mesh size in different postures

What's the optimal method in Unity to match the size of a Capsule Collider to the actual size of the game object it is part of? To understand what I'm trying to do let me give an example: I have a ...
160 views

### Detect walking on floor - works partially

I have a set of Gameobject blocks that form a floor with Box Collider and a GameObject with a Box Collider in it. My first hunch detecting hitting the floor was: void OnCollisionEnter2D(Collision2D ...
815 views

### How do I efficiently check if a point is inside a rotated rectangle?

Part for the sake of optimization, part for learning purposes, I will dare to ask: How can I most efficiently check whether a 2D point P is inside a 2D rotated rectangle XYZW, using C# or C++? ...
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### Collision detection with moving objects

I searched a lot about this problem. I found many answers here in Stack Exchange but none of them really answers when positions for objects get updated. For a game with fixed size map and that has ...
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### XNA Collision In An Entity Part System

I've hit a loss in creating a "game engine" in XNA, I'm extremely confused over how to approach collision in an Entity-Part System ( following this as a reference ). I can make all the entities with a ...
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### 2D Collision Box Clipping

There is this strange issue with the collision in a game I am making. When the player is slightly lower than a block it is colliding with from the side, the player ends up clipping to the top of the ...
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### Detecting collision with walls (is this a good solution?)

I'm trying to make the collision smooth (it must open the animation, but not move the character). I've implemented 'fake positions': int step = 20; fake_left_x = x-step; fake_right_x = x+step; ...
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### What is the most efficient way to determine collision path

I am trying to create a game in which I need to know if two objects will collide in the future, and when. I have both object's position, radius (they are circles) and velocity. A specific example of ...
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### Platformer collision problems

I am working on a platformer 2D, and i am currently focusing on collision. I have the actual rectangle(class: Rect) and i can detect if the player-model is intersepting it. However, when it comes from ...
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### Most efficient way to get the world position of the 8 vertexes of a Box Collider (C#)

What I am looking for is the most efficient way to get the world position of the 8 vertexes of the Box Collider of a freely rotated Gameobject. I cannot use collider.bounds since object is rotated, ...
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### Detecting the two Vector3 that determine the bottom-edge of the side of a box-collider that had collision (with C#)

So, I understand that plenty of questions have been posted on how to detect which side of a Box Collider had collision. However, what I am trying to achieve is a little different. I want to find out, ...
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### Combining Many Small Colliders into Larger Ones

I am creating a game using a tile-map made of many thousands of grid squares. At the moment, each square has a square collider on it for checking collisions. However, with many thousands of tiny ...
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### How can I exploit multithreading in collision resolution?

I'm trying to speed up my collision resolution by using multiple threads. I'v read through Box2D's source code and while it was challenging and educating, it didn't really point me to how I could use ...
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### Ray & Segment Intersection

I'm writing some code to check intersection between all of a rectangles segments and a ray. It will sometimes use the Left and Right side of the rectangle as the closest face hit (face DA & BC) ...
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### JBox2D Collision Detection

how can i detect a collision between two fillOval with the physics engin?? i read the manual but i can't understand where i may write my code. i want to simulate the fall of 2 balls and catch the ...
844 views

### Colliding without physics in Unity: is it possible to put OnTriggerEnter in the moving character?

My main question is: is it possible to put OnTriggerEnter in a script that goes attached to the moving character instead of to trigger area/object? Let me explain my exact need. I want to detect the ...
228 views

### How do I check for collision between an ellipse and a rectangle?

I am working on LibGdx framework for developing a 2D isometric tower defense game.All my sprites are drawn in 2D isometric view. I have used an array list to store 8 points at boundary in the ...
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### How do I create a draggable object which snaps to obstacles in the way?

I bring yet-another-drag-with-mouse question (I am using Unity with C#), but with a less common particular detail: the existence of obstacles in the middle of the way trough which dragging occurs (3D ...
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### My Sprite is disappearing when it collides with my floor (libGDX)

I am just starting to build the game "engine" and I am using a sprite drawn in the same position as a rectangle and the two always move together. I have another rectangle which is the floor when the ...
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### Spawning Object 1 Within Object 2's Collision Box [Gamemaker]

I was wondering if any of you could help me with a specific Gamemaker question. Am using Gamemaker Studio. I have an object (oSpecialSolid) which rotates and moves across my level. At random ...
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### Player Flying after colliding - Unity

I have a Player with a capsule collider on him and i have various objects in the scene. Most of the objects have either mesh collider or box collider enabled. When i move my player and the player ...
161 views

### Circle inside ellipse collision/intersection (preventing circle from leaving the ellipse)

I am working on a 2D RPG with a turned based battle system. Characters move inside the confines of an ellipse movement area and when they leave the boundaries will be pushed back inside. (i.e they ...
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### Soft Body Collision with Box2d (libGDX)

I've made a few classes to create soft body objects in libGDX using Box2D (specifically a circle and rectangle similar to these links). The objects are constructed of a number of circle shaped Box2D ...
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### Bounding Volumes for Empty Space

I'm creating an Android game that relies heavily on collision detection for a couple of players (at least up to 4). I researched hierarchical structures that could speed up the process. Because I have ...
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### Fastest 3D bounding box algorithm

I am at the point in my game where I need to add a collision system. I tried jBullet, and while it did work, it wasn't what I was looking for. I just want a simple way to test if two oriented bounding ...
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### Move collider along with model with Mecanim jump animation

I've been creating an infinite runner game in Unity3D for a while and I got stuck in this point that whenever my character jumps using Mecanim system his model (mesh) goes to air but his attached ...
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### Continuous Collision Detection

So I'm playing around with the separating axis theorem and collision. Obviously the problem of what face it collided with arose. I need the unit normal which is tangent to that face it collided with ...
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### simple solution for 3d collision detection and response

I'm having great difficulty trying to implement collision detection and response in a 3d game What are some simple solutions someone can use to implement smooth collision and response similar to ...
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### Unity - Raycast not hitting to BoxCollider2D objects

I'm working on 2D and I have a Quad as background. And some wall sprites over this quad : I'm instantiating wall prefab sprites over quad when user click to somewhere. But I don't want to ...
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### Field of vision - Objective-c

Here's where I'm at. Here's where I want to be Here's how it's drawn SKShapeNode *fov = [SKShapeNode node]; UIBezierPath *fovPath = [[UIBezierPath alloc] init]; [fovPath moveToPoint:CGPointMake(...
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### How is curved 2d ground is implemented in real games?

I'm developing a 2d platformer (inspired by N game) and I already successfully implemented circle-convex, convex-convex and circle-circle collision. But now I want to be able to make platform that ...
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### XNA 4.0 - Bounding Boxes

So i'm kind of new to programming and im trying to check collision using bounding boxes. i'm currently stuck as to how to call my bounding box within my bounding box function as shown below public ...
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### TileMap or Voxel collision detection

I have a conceptual question: In the case of Tile Map, each block has the information from the enemies who are going about it. But what if some of these enemies are far greater than the block? I have ...
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### Before I change position I want to check if the gameobjects are collinding

For starters I'm new to Unity3d. So my question is when I click on an object I want to change its position but without collinding with the other objects and I need a function to check that. I already ...
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### Unity - How to detect collision on child object collider

How can we make to the event "OnTriggerEnter2D" collisions on the objects children of the object with the c# event script? Look this: Is there any way to assign the event using "Delegates"? ...
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### Java 3D collision detection with JBullet

So I have spent a long time trying to work on a collision detection system from scratch for own game engine and came up fruitless due to lack of time. Finally I decided to try to use Jbullet to try to ...
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### Rotate Object inside room according to wall

I have a room. I am trying to move an object whenever it collides with a wall. It's working properly except at the edge of two meeting walls. At the edge it's flicking. I tried to move the object when ...
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### How can I calculate the bounding box of a 3D model?

I am making a game in OpenGL and Blender and trying to use JBullet as the collision manager. I am using BoxShapes for collisions, which requires a javax.vecmath.Vector3f representing half of the box ...
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### BoxCollider not blocking other object(s)

I'm really newbie , watched about 20 videos about and tried to do something. But I still have problems with collisions. I'm working on 2D. I have a Sprite and a Cube (GameObject>3D Object>Cube). ...
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### Is it possible in Unity to Flip a 2D Sprite Without Flipping the Object it is Assigned to?

I 'built' (followed a tutorial) on a collision detection system, and when I flip the object to go left and right the collision messes up. So I have three options; find a way to modify the collision ...
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### How do I prevent raycast car wheels sliding sideways?

I've been writing a non-realistic car physics engine as a learning exercise, using this article as a reference. I have a car that correctly collides with a terrain and applies the correct suspension ...
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### Predictive Collision Detection - Find Time Of Impact

I have a green box at a starting position A. It can move along two paths A to B is linear motion A to C is under the influence of gravity (non-linear) The thin vertical line is a fixed colliding ...
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### Where to put the screen dimensions to make it accessible for all on screen objects?

I'm starting game development to learn a new language (SDL2, C++) and would like some opinions on the best way to handle a probably very basic problem. I don't want my player to go off screen, so I ...
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### XNA4\ Monogame 3d Collision detection Help please

i have been trying to get 3d collision working for a while and i think(hope) you people can help me so for my project i have created a 'sprite3d' kinda class which is called ModelEntity and there ...
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### Smooth Wall Collision Detection

I've been working on a small game, and I've been stuck on the collision part. During the collision, when my player hits a block, he stops just as it should, but it then doesn't allow me to another ...
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### Platformer Tile Map Collision Help

I've been working on a small platformer as a simple project but, I'm having troubles with my collision detection. What I want is that as the player falls due to gravity, it will stop when it touches ...
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### (Unity) Drag and detect object below when dropping

I'm studying game development in Unity and I want to create a idle/clicker game like Cow Evolution. I'm using OnMouseDown, OnMouseDrag and OnMouseUp to move the GameObject around the scene. Now I ...
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### On key press, spawn a collider where my player is facing?

I'm trying to create an attack mechanic to my player hero in my 2D Tower Defense game. When I press the Q button I want my hero to do an animation and spawn a temporary collider shaped as a cone at ...