Questions tagged [animation]
The animation tag has no usage guidance.
41
questions
0
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0answers
23 views
What do you do when the root skeleton is not defined in a gltf file?
Cross posting from stack overflow:
Reading the source code of tinygltf I see this:
...
1
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1answer
20 views
Why are these 2 buffers joint while extracting glTF information?
I am using tinyGLTF to parse gltf files and then render them in my program.
I am currently during the third example in this page.
In particular I am trying to extract the 2 animation buffers:
My code:...
1
vote
1answer
50 views
What's the simplest, open, animation format?
I have an obj parser that handles triangle meshes specifically.
I want to extend it (and the rest of my system) to handle animations as well. However, I don't think I am ready to tackle the glTF ...
0
votes
1answer
53 views
Keep constant number of visible circles in 3D animation
I have created a 3D animation with a perspective projection of white circles moving randomly in a fake 3D space projected on a 2D computer screen (GIF 1).
Since I need to keep the same number of ...
3
votes
1answer
99 views
What is the point of having integer-based draw routines in software rasterizer?
I wonder why all the well known algorithms of drawing for example circles (bresenham, mid-point, etc) all use integer arithmetics? For example, here is a simple circle drawn with bresenham algorithm:
...
0
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1answer
82 views
Compute Speed of Spheres in 3D animation
I have created two animations:
One where a "camera" moves towards the spheres creating an optic flow (1st GIF).The code can be found here.
One where spheres move randomly in a 3D coordinates space (...
0
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0answers
26 views
Apply a pose to a 3D model/mesh
Assuming that I have pose information for a human, is there any ways/tools to apply that pose to a 3D model?
Basically, given continous pose information say from a dancing person, I like to animate a ...
2
votes
0answers
82 views
Pitfalls of animating with quaternions
When working with animating a rig, quaternions are often used for rotations. However sometimes we need to clear rotation along given local axis of a joint. With quaternions it's not as simple as just ...
1
vote
1answer
207 views
Why do animated CG characters always feel fake?
Why do animated CG characters always feel fake?
Usually if a CG character is an animal (or humanoid creature), they tend too look kinda off. Their movement tends to look oddly smooth or lightweight, ...
1
vote
1answer
36 views
Consistent animation speed across systems
I recently noticed that in all games, no matter what system you play on or what specs you have, your character will always move at the same speed even if there is no frame rate limit. I was wondering ...
2
votes
1answer
60 views
Should animations be locked to FPS or Fixed time
I have been working on a 3D engine and I am now implementing animations, but I can't find out whether or not to use the FPS of the engine or a fixed time method for the transformation's speed. Could ...
3
votes
1answer
170 views
What algorithm is used in this animation from Tatami Galaxy?
Is there a name for this type of effect where many area sizes are increased/decreased in relation to each other? I'm looking for some type of algorithm, formula, logic, etc. for recreating this. Here ...
2
votes
1answer
68 views
What noises can be sliced?
A well-known property of Perlin noise (with FBM) is that if you take a slice of it, the result is still Perlin noise. So, by taking successive slices of 4D noise, you get smoothly shifting 3D noise, ...
0
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1answer
93 views
Which techniques do I need to animate a 3D model in my homemade engine
Suppose I am making my own C++ 3D engine; I can already load a 3D model using assimp, display it with phong lighting, and I now want to animate it.
I'd like features in my engine to, say, load a run ...
1
vote
1answer
682 views
glTF animation keyframe question
I have an animated cube with 5 keyframes and when I export it to glTF with blender, in the file I can only see 3 keyframes:
But when I viewed the gltf model with viewer all 5 keyframes worked well ...
0
votes
1answer
28 views
compression of gif animation
I have a parchment animation at singingdays.co.uk that is a rather large file of about 80mb which obviously is taking a long time to download. I have managed to compress it down to about 60mb using ...
0
votes
1answer
76 views
kinematics and dynamics of a sphere in a spring mass system?
I am attempting to code a simple spring mass system simulation in which a sphere pendulus hangs from a string (a spring) by the top and then another sphere (controlled by the user) can move and ...
2
votes
0answers
99 views
Triangle-based and vertex-based skinning models?
I'm reading the Loper et al. 2015 paper on the Skinned Multi-Person Linear Model and I came across this:
What we would like is a vertex-based model that has the expressive
power of the triangle ...
2
votes
1answer
959 views
How can I use 3d animation to create a character that uses sign language?
I performed a quick search on programs that translate natural language to sign language (through a 3D animation character). Here are examples:
IBM SISI
ProDeaf (which is an android app)
My question ...
5
votes
2answers
416 views
Was Evans & Sutherland CT5 really created in 1981?
A few days ago I found a video on Twitter showing the Evans & Sutherland CT5 Flight Simulator system. It was labeled as 1981 footage and looked really amazing. The first time I saw similar 3D ...
2
votes
1answer
120 views
pseudoinverse Jacobian and adding more control in computer animation
I am studying inverse kinematics.
But I wonder the suggested equations.
(The following equations are taken from 'Computer Animation Algorithms and Techniques Third Edition Page, 181')
To better ...
1
vote
0answers
65 views
General interpolation practices
Say my animation scenario contains one mesh interpolating into another (possibly approximating over other meshes), using Bezier curves.
I know that for smooth surfaces, where normals can be ...
2
votes
0answers
70 views
Interpolating normals during animation
I'm doing linear tweening of a cyllinder to a cone of equal radius and height in OpenGL. I know parametric equations of both of them, so I derived vertex normals accordingly. Now, I know, that proper ...
1
vote
1answer
54 views
Is it possible to draw the intersection of two squares of known dimension using only x,y coordinates and without an if statement?
Say I have two squares, both 10x10, with some small, unknown overlap.
Is there a way to draw the intersection of these two squares using the width, height and x,y coordinates of each square, while ...
2
votes
0answers
100 views
How are fluid simulations handled in Computer Graphics?
How are fluid simulations handled in Computer Graphics? For a novice, there are hardly any novice friendly tutorials explaining how particles or fluids can be simulated.
Things like smoke, crown ...
3
votes
1answer
89 views
Need help reasoning about video oscillation >60hz
I want to make a basic video oscillator for the web. What I want to do is basically illustrated in a tutorial for Lumen: essentially, I want to define an oscillator to turn on and off a color signal ...
5
votes
2answers
1k views
Pixel dispersion (dissolving) algorithms
This YouTube video of a flip-dot display (physical b/w pixels) shows the reverse of an effect that might be called dissolve or dispersion, i.e. a text emerges from noise by pixels moving in to form ...
2
votes
1answer
388 views
Inverse Kinematics with more than 2 segments
I'm building a 2D inverse kinematics system and can't figure out how to find all the joint positions. I have the math to make a typical IK set up with a single bend (e.g. arm, leg), but I get stuck ...
4
votes
1answer
503 views
Calculating Skeleton-Deformed Mesh Normals
I'm implementing mesh skinning in a project of mine. I can calculate vertex positions based on bone transformations, but I've run into a problem with calculating their normals.
From the resources I'...
2
votes
0answers
71 views
smooth zoom animation formulas (and rounding numbers)
I need to generate an easy animation video in Python (I use PIL to create every frame, then combine them using avconv). The animation is just an image being zoomed ...
4
votes
1answer
132 views
How does a rigged model work?
What black magic is behind this?
Starting from a pile of polygons, a skeleton, and an initial conformation, how is a new conformation turned into a new pile of polygons?
3
votes
2answers
525 views
Storing 3D animations for ray tracing
I've just finished writing a path tracer that takes OBJ files and renders it. This is convenient for still images, but my end goal was to export a sequence from a 3D application (Blender was what I ...
7
votes
2answers
7k views
How to achieve gimbal lock with Euler angles?
I was studying about Euler angles and I came across the problem gimbal lock which can occur by using Euler angles. In gimbal lock we lose one axis of rotation.
But how? And when does it happen? On ...
0
votes
0answers
230 views
How to do keyframe interpolation on matlab?
I want to do keyframe interpolation in matlab.
If I understand correctly, it uses splines to approximate the the motion of specific pixel points within the frames(through transforms). Correct me if I'...
2
votes
0answers
260 views
Coordinate system transformation in motion capture files
I am trying to align two motion capture files from different sources.
The motion capture file consist of a skeleton specified as a hierarchy of joints. Each joint i.e. "shoulder" has three pieces of ...
5
votes
1answer
202 views
Questions about Preconditioning Conjugate Gradient method in Baraff & Witkin 98?
I encountered some problems when implementing the cloth simulation algorithm from Baraff & Witkin 98's Large Steps in Cloth Simulation.
Baraff & Witkin 98
Consider the cloth as a particle ...
3
votes
1answer
238 views
Spine. What is the name of the process?
https://www.youtube.com/watch?v=twUz99ek5do&list=WL&index=5
There is a process from 1:51, where the guy start making polygons around the bodyparts. I think this is this part is where (with ...
1
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1answer
71 views
How to design something like this? [closed]
I am very eager to know what technology might been used to implement this piece of wonder:
Any idea?
I think, it's ray tracing. What do you think?
1
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0answers
62 views
How is smooth animation accomplished? [closed]
How are objects moved smoothly from point A to point B given matrix transformations that describe next position?
3
votes
2answers
157 views
Software to compose separate models into an articulated model?
I've inherited a system which animates a humanoid avatar by loading various models and manually calculating transformations for each one. I'm in the process of porting part of this system to Three.js, ...
14
votes
1answer
205 views
How can I model distant rain?
Close up, rain can be modeled as transparent balls of water with appropriate motion blur. This seems impractical for large volumes, which would be necessary for scenes of rain in the distance.
At ...
