# Tagged Questions

3D refers to three dimensional space where coordinates are represented with X, Y and Z values.

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### Connecting a model's joint to the joint of another model

I am trying to figure out the math behind orientating and translating a model so that a specified point on the model will connect with a specified point on another model. For example, given the ...
149 views

### How to rotate an object so that it is aligned with a vector?

I have the following Scenario: Two moving objects (A and B in the picture) need to appear "connected" by a third one (C in the picture). I set the position of the connecting object C as "halfway" ...
165 views

### Supersampling - Pixel color average calculation

I am currently trying to understand Supersampling. Wikipedia says (or at least Wikipedia tells me) that multiple color samples are taken from one pixel to calculate the final result. But to my mind ...
2k views

### OpenGL light appears to move with camera and changes with object rotation

I have a working open gl es 2.0 3d engine (my own) that I've used in several iOS apps. I recently noticed that on a mutli-symmetrical object the lighting didn't look the same at each rotation. For ...
1k views

### model view projection multiplication order

I'm debugging a lighting problem where the camera position is effecting the diffused lighting component on my 3d model. In researching my problem I went back and am reading over all the how to ...
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### How can I generate isometric sprites based on a 3d model? [duplicate]

I'm wondering about the following: I'd like to create isometric sprites for a game that I'm currently developing. Rather than asking an artist to draw numerous sprites (which will be quite costly), ...
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### Picture got distorted after has been moved to Directx11

I have moved app from Directx9 into Directx11. After this upgrade strange thing happened with my world. Objects get skewed and became 2D, also they are clipped in unexpected places. Two arrows at ...
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### How can I handle position in an entity system where position can be 2D or 3D?

I'm working on a game engine to learn how it's done (so I might better take advantage of the techniques involved and other, similar engines in the future), and I've run into a problem when handling ...
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### XNA: “TextureCoordinate0” missing, but I'm not using textures

I'm trying to create a voxel game using XNA, but I'm getting a somewhat bizarre error when calling DrawIndexedPrimitives(): InvalidOperationException was unhandled The current vertex declaration does ...
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### How crucial is 3D terrain in a classic RTS game? [closed]

My love of RTS games is from the days of Warcraft II, C&C, etc, when top-down/isometric views were king and terrain was generally tiled and flat. More modern games - as CPU/GPU power increased - ...
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### What are “supporting points” in the context of the SAT?

I am currently implementing a separating axis theorem collision response. It can be used by oriented bounding boxes and axis-aligned bounding boxes. So far I have covered face-something contacts. I ...
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### Specular light flickering with high specular power

I'm having some issues with specular lights, to be more specific, the specular color seems to be flickering when I set high power, like 512 (I set the specular color to green, so you can see better): ...
291 views

### How can I implement a camera like the one in RotMG?

RotMG, an MMO top-down shooter, takes on a unique 2d-3d style, and has an intriguing camera; The game is obviously 3d, not simply isometric, and if you play the game and turn on camera rotation you ...
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### Alpha blending, transparence and z-ordering

I'm making some tests with alpha blending in a projet and I don't understand something. In my tests I've done something like that and everything look good: Draw blue box first (depth test: true, ...
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### How can I create the illusion of a 3D object moving around in a static background?

I'm designing a Resident Evil clone using OpenGL. I'm curious how the older Resident Evil games used a static pre-rendered background with 3D models roaming around: Here, if the main player (Claire)...
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### What is the meaning of the row “opposite” the translation column?

Usually, I do my matrix multiplication like this: [1 0 0 dx] | [px] [px + dx] [0 1 0 dy] | [py] [py + dy] [0 0 1 dz] | [pz] = [pz + dz] [A B C 1] | [1] [1] Where the translation is along ...
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### Why bother with a separate normal matrix, if there is never non-uniform scaling on the view matrix?

I am updating one of my shaders to a version of OpenGL/GLSL that doesn't automatically provide gl_NormalMatrix (for educational purposes; I'm not ripping out working code for the sake of it). ...
285 views

### Rendering a Voxelized Mesh [closed]

I've been reading many papers about how to voxelize meshes using different GPU techniques, but I've ran into a problem that I'm not sure how to solve properly. I understand the process of how to ...
154 views

### Custom 3D Noise function incorrectly generating in Lua

I have been working on a custom noise generator (not Perlin on Simplex or whatever), which works fine in two dimensional space, but upon converting it into three dimensional space, it turns into a ...
185 views

### Get quaternion between two objects on sphere

In a planetary gravity environment objects are represented in the following way: struct object { struct quaternion quat; // quaternion to represent the rotation between the object and the center ...
138 views

### Why Is My AABB Collision Detection Not Working

I am going to be making a 3D game and I need to be able to test for accurate collision. I was able to get bounding sphere collision working (too inaccurate to be used for the whole game), but AABB ...
153 views

### How do I detect collisions between a particle-based net and a ball?

I've implemented a net using Verlet integration and many points connected with constrains; like this demo, but in 3D. I want to implement collision detection between this net and a ball (like in a ...
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### Infinite loop of prerendered 3d graphic

I have a game where I want a never ending pathway for the character to walk along. So in my 3d modeling tool I created a path like this: now I want to loop that model over and over in my ...
134 views

### Rotate an arrow on a plane?

I'm creating a display for a GPS-based embedded system and would like to have an arrow indicating the current bearing. I'd love the arrow to have a 3d appearance by rotating it on a plane tilted up ...
110 views

### 3d game math problem [duplicate]

i'm very much new to 3d math operations. I know how to rotate 3d points certain degrees arbitrarily by any axis but we were given a strange problem to think on. I'll spare using actual numbers on it,...
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### Fixed joints in 3D

I'd like to build something like rigid origami in 3D space. So I need some mesh where each vertex is a particle and the set of the edges makes a chains/fabric where each edge is a "fixed length" ...
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### Should I bother merging faces in my 3D block-based game?

Okay, so I have a bunch of cubes in a 3d-world. I already implemented face culling, so that when a cube is next to another cube, their touching faces won't be drawn, or even sent to the buffer. ...
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### How to find the 3D object the camera is pointed at

I'm currently developing a 3-dimensional game (the first I've ever done and it's not as hard as I thought it would be!), but I've run into a little bit of a snag. I want to find the current block the ...
284 views

### XNA C# 3D game Wall collision response glitch

I have been working on a reliable physics system in my code and so far it's ALMOST working. :D I am aiming for wall "sliding" style of collision response, like you'd expect it to work in commercial ...
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### How can I inspect 3D model exactness? [closed]

I am neither a game designer nor a graphic designer. I am a .Net and C# software developer. I have a game project and I've still been studying to learn game concepts and technolgies for a year. I'...
558 views

### How do I implement melee hit boxes for a top-down game?

For a 3D top-down game, how should I handle collision in melee combat? My game has no targeting system, so I can't use a simple distance check between attacker and target. What I am thinking is have ...
479 views

### Mouse click movement

I need to make realistic human movement (3D) using mouse click. Get mouse click point using Raycast. Smoothly Slerp to LookRotation. Move transform.forward. Everything works fine, except I have ...
1k views

### Opentk LookAt() and 'eye' argument rotating

I'm trying to create rotating camera, which looks down by 45 deegre like this: However my code for rotating eye vector is not working properly and I achieve vertical rotation, when it should be ...
710 views

### How do reflections work for large flat surfaces?

I understand how reflections work for objects. A cubemap would be rendered around a certain point in 3D space, usually at the center of the object that the reflection is to be applied to, and that is ...
309 views

### XNA - DrawIndexedPrimitives or DrawUserIndexedPrimitives?

When rendering primitives in XNA, does it matter if I use DrawIndexedPrimitives() versus DrawUserIndexedPrimitives()? RB Whitaker uses the former, while Reimer's uses the latter. From what I can tell,...
155 views

### HDR and Alpha Blending

I've been reading a lot about HDR techniques and came across Alpha Blending compatibility. Searched even more and found this snippet from the Ogre Forums: With source alpha blending, it sometimes ...
3k views

### How can I create a stretchy, breakable pizza cheese material?

I want to create realistic pizza and allow user interact with it. What I want: What I created: I created model of the pizza (8 pieces) in Blender, then imported it into Unity. The piece of ...
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I'm confused about the mathematics behind additive blending used in conjunction with Phong shading. Intuitively, it seems like you would need to use a floating-point framebuffer and some sort of tone-...
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### How can I do a weighted cascade down a path in a 3D environment?

I am trying to perform a weighted cascade down a path in a 3D environment. Now, what I am trying to do is have one object(a cube) in the environment scan from its coords 1 in every direction for ...
2k views

### Unity3d wheelcollider falling through terrain

I have created simple project with 3D car and terrain. I have added 4 Wheel Colliders on model wheels. But when I run project wheels falling through terrain. Before run: After run: I am sure that ...
277 views

### Quaternion Rotation Help

So I'm making a little engine with DirectX 11 and C++. (Some other help from other API's as well) DirectX has this function XMMatrixRotationQuaternion(XMVECTOR quaternion). I know nothing about this ...
179 views

### Finding a vector perpendicular to a current vector

Assume, that we have a player that has a vector direction. We have an enemy, that is shooting a player. And the task is to find out from which side the enemy is shooting. I know the algorithm, how to ...
140 views

### X, Y, Z rotation around camera

I'm making a 3d orthogonal-projected, game using painters' algorithm in java. I'm able to rotate the objects with incremental rotations (e.g. rotate all objects 10 degrees) using affine ...
202 views

### More vertices vs more textures

I'm currently working on a dynamic 'door' creator, and I'm trying to decide which is more efficient. Not much experience with 3D render speeds, so I'm asking before I choose which direction to go ...
118 views

### Colision detection of disc (Maximum Material Condition aka “Flatness”)

I have a 3D-laser scanner which gives me a series of points of a real-world object. The points are related by a common origin. I know I can derive the equation of a plane from 3 points and that the "...
196 views

### 2 component unit vector

Is it possible to store a 3d unit length vector with only 2 components, for example as coordinates on a unit sphere? It seems possible but I have never seen anyone do this. Would this be at all ...
672 views

### Unity plane that is normal to Z axis

I want to create a plane that will be normal to the Z axis, but I am having difficulty visualizing what rotation it needs to have. I want to have a top-down view upon the plane such that I can use ...
198 views

### Vertical Collision Detection, Falling Through Ground

After much work trying to learn collision system theory and apply it, I've got my collision system working for the most part. The player can collide horizontally with no issue, sliding against walls, ...