/r/computergraphics

Photograph via snooOG
Welcome to r/computergraphics.

This subreddit is open to discussion of anything related to computer graphics or digital art.

Computer Graphics FAQ

Submission Guidelines

Anything related to CG is welcome.

  • If you submit your own work, please be ready to receive critiques.

  • If you submit other peoples work, please give credit.

For more information about posting to our subreddit, read the r/computergraphics FAQ

Technical Questions?

Here are subreddits dedicated to specific fields:

r/vfx
r/GraphicsProgramming
r/MotionDesign
r/Programming
r/gamedev
r/Low_Poly
r/archviz
r/3Dmodeling
r/DigitalArtTutorials

Software Questions?

Questions about specific software. We'd love to help, and please feel free to ask, but these software specific communities may be able to provide you with more in-depth answers.

r/Maya
r/3dsMax
r/Cinema 4D
r/Blender

/r/computergraphics

53,310 Subscribers

3

Getting into stylized character modeling and animation recently, feedback appreciated!! (Yes, I'm already aware of the imperfect loop of the walk cycle)

0 Comments
2024/04/05
21:37 UTC

5

Project Zomboid - School Bus base by artforge 2024

1 Comment
2024/04/04
12:57 UTC

2

Particle tutorial with 3ds Max, TyFlow and Krakatoa

0 Comments
2024/04/04
12:25 UTC

2

Explanation of the Matrix4x4 class, source code in video description

0 Comments
2024/04/04
08:09 UTC

10

Realtime Refraction with SDF, Raymarching and some interesting Boolean Operations

1 Comment
2024/04/03
09:41 UTC

0

ATOM PUNK

0 Comments
2024/04/02
14:45 UTC

1

Handling Border Vertices in a Partitioned, Dynamic LOD System

I'm currently working on implementing a basic partitioned, dynamic Level of Detail (LOD) system for a square 3D terrain, which I've divided into quadrants. I am attempting to implement the data strcuture described in this paper (https://x3dom.org/pop/files/popbuffer2013.pdf), which utilizes aggressive geometry quantization to sort triangles based on their precision level, thus creating a nested, progressive structure.

The core of my issue lies in managing the quantization and rescaling of border vertices. According to the paper, all vertices within a partition map to an integer grid (ranging from 0 to 2^q - 1) based on the partition's specific bounding box. These quantized vertex values are truncated and rescaled back to the terrain's original object space, depending on the required LOD and the partition's bounding box. This process, however, introduces cracks along the borders of partitions with differing LODs.

To address this, the paper suggests protecting the positions of all border vertices by using the highest possible quantization level (l = q) during preprocessing. These protected vertices are flagged, and their high-precision coordinates are considered when computing degenerate triangles.

Here's where I'm stuck: Consider the top left quadrant of a square 3D surface/terrain. The bottom right corner vertex of this quadrant, being on the partition's border, would have a quantized grid value near the maximum. However, this same vertex, when part of the bottom right quadrant, would likely have a value near the minimum due to the different partition bounding box. Ensuring the correct rescaling of these border vertices requires using the same bounding box for rescaling as was used for quantization, which presents a challenge given my current use of simple vertex and index buffers. This might necessitate duplicating border vertices in the buffer and completely reindexing the triangles, which seems both inefficient and different than what the paper intends.

My tentative solution involves streaming the original, full-precision float values for the vertices and rendering border vertices at full precision, but this approach diminishes the benefits of reduced data streaming.

Is there a more efficient way to handle this issue without losing the advantages of the POP buffer method? Any insights or suggestions would be greatly appreciated. If this post doesn't belong here, please let me know, and I'll remove it. Thank you!

0 Comments
2024/03/29
14:42 UTC

3

Looking for a Shadow-Casting Technique for 2D scene

Hello, I am trying to implement shadows in my 2d game but im not really sure how to implement them.

This is how I would like them to look:

https://preview.redd.it/64bh0cu3yxqc1.png?width=2050&format=png&auto=webp&s=177fe86a58bad410052ee51e98105a20bfb8ba25

The green should be the shadow penumbra and should be kinda blurry.

Shadows should only follow a "shadow_dir"

I dont know if I should learn shadow mapping or raycasing?

Thanks

3 Comments
2024/03/27
21:02 UTC

1

Differences between Blinn-phong and phong illumination model?

Just wondering what are the differences/improvements made.

Is it just for illumination model or for shading models too?

3 Comments
2024/03/26
10:31 UTC

5

Phong illumination model - where can I find more explanation of these equations? (It’s not in the original paper)

9 Comments
2024/03/26
10:30 UTC

0

CYOA Research Questionnaire

Currently I'm in the process of making a choose your own adventure (CYOA) style fantasy first person 3D animation in Unreal Engine about an adventurer delving into a dungeon to acquire a magical artifact to save his village, for my college course. It would appreciated if you would fill out this questionnaire to help me with my project.

https://forms.gle/qGpBvJdwXuycK5rV9

0 Comments
2024/03/26
02:19 UTC

11

Dithering Algorithms implemented in real-time (explained) c++ opengl

0 Comments
2024/03/25
20:39 UTC

5

Parametric Curve to Mesh techniques?

1 Comment
2024/03/24
03:43 UTC

1

Looking for help about a shadertoy animation

As explained on my web page https://www.motionmountain.net/prizes.html#pld
I offer prizes for those who can help me to improve the shader https://www.shadertoy.com/view/cld3zX by taking out the mistakes of the rotating triangle at the centre.
See https://www.motionmountain.net/charge-mass.html#et for the desired triangle that should rotate.

The motion should be inspired by this: https://www.youtube.com/watch?v=DHFdBWU36eY&t=50s

Any help is welcome!

https://i.redd.it/0nv7rjvwt5qc1.gif

2 Comments
2024/03/23
22:27 UTC

4

Research material on simulation of material damage from collision in 3d rendering pipelines

I am looking forward to research on this topic, which if unclear can be further explained as finding a way to simulate if not estimate how 3D objects and their material properties will take on and display degradation / damage as a result of collisions among them. This could be a multi step approach as it involves calculating damage heat maps, cracking simulation and then maybe of course writing special shaders to emulate the damaged material properties.
Hoping the above clarifies my topic of interest, I am looking for some help with the literature review.

I have tried my luck on google but to no avail. I've been getting results mostly unrelated to the topic.
Hope some of you might be able to let me know of some research material already published in this domain.

Also, any comments on the trivial or non-trivial nature of the topic, and how well you think this might work out for a Computer Science master's degree research are also appreciated.

Thanks.

2 Comments
2024/03/23
21:22 UTC

1

Brainstorming - Cascaded Shadowmap Bugfix

I have been trying to implement Cascaded Shadow Maps on my game engine, but, for some reason, I can't get it to work right! It seems so close to being right, but, by the looks of it, the shadow transformation to world space seems not to be working correctly.

I have tried everything, to no avail. Maybe there is something I haven't tried yet? I honestly just need some fresh ideas that I haven't tried yet

https://preview.redd.it/x4y589fqkxpc1.png?width=1593&format=png&auto=webp&s=82d0a128c0aa03ee39d46e9eb4431f94170d46ce

https://preview.redd.it/4jzohnackxpc1.png?width=1599&format=png&auto=webp&s=6bdc473ebba775d6e6d78c0d0524e825a431cd83

0 Comments
2024/03/22
18:39 UTC

0

VR Hand in AR on the Browser

positive-intentions

It is common in mainstream augmented reality (AR) products for there to be a way to interact with virtual objects. I wanted to investigate the options for when using browser-based AR. I'd like to hear your thoughts on the approach.

The folowing is an experimental proof-of-concept. (You might need to give it a moment to load if the screen is blank)

https://chat.positive-intentions.com/#/hands

Using TensorflowJS and Webassembly, Im able to get 3D hand-pose estimations and map it to the image from the webcam. This seems to work well and is reasonable performant.

Next steps:

  • Introduce a rigged 3D hand model to position relative to the observed hand from the cemera.
  • Add gesture-recognition to help estimate when a user might want to do an interaction (point, grab, thumbs-up, etc)
  • Send hand position details to a connected peer, so your hand position can be rendered on peer devices.

Note: There is no estimate on when this functionality will be further developed. The link above is a preview into a work-in-progress.

Looking forward to hearing your thoughts!

0 Comments
2024/03/22
10:04 UTC

1

What's opengl context and window mean?

Hello, everyone. I'm a noob to computer graphics. I'm trying to readlearnopengl.

So, I know OpenGL it's a specification. The book mention that context is a state machine, so I think context is just a collection of variable.

The book say that we need to create context and application window, both are OS related.

Why context(a collection of variable) will be OS related? What context actually is?

And what is an application window, I mean how to implement an application window if we do not have OS window API and just assemble language or c language?

Thank you guys.

1 Comment
2024/03/22
04:12 UTC

1

CYOA Research Questionnaire

Currently I'm in the process of making a choose your own adventure (CYOA) style fantasy first person 3D animation in Unreal Engine about an adventurer delving into a dungeon to acquire a magical artifact to save his village, for my college course. It would appreciated if you would fill out this questionnaire to help me with my project.

https://forms.gle/qGpBvJdwXuycK5rV9

0 Comments
2024/03/21
11:09 UTC

3

Medical Animation Showreel 2024 | Random42

0 Comments
2024/03/21
10:21 UTC

4

ELI5: CPU rendering vs GPU rendering

Looking for a straightforward birds eye view explanation.

The more I read about it the more I confused I get

26 Comments
2024/03/21
07:51 UTC

1

Inaccurate colour interpolation using rgb & HSV

Given we have half blue mixed with half white in rgb space we would not get light blue but a purple ish colour.

Just wondering why rgb have this inaccurate colour interpolation.

And HSV is supposed to fix this issue, but how exactly do we do that?

Many thanks

6 Comments
2024/03/21
07:45 UTC

1

If we can represent CIE colour space using r,g,b axis why can’t we represent all the possible visible colours using rgb?

If we can draw the 3D CIE chromaticity using r,g,b axis, why can’t we a 100% coverage in real world use?

2 Comments
2024/03/21
07:43 UTC

4

GLSL Spherical Harmonics

I've been trying to make a shader for Substance Painter that converts the environment HDRI to SH coefficients. Any example shaders or code I've found only works by using multiple external shaders/buffers/etc, which Substance doesn't allow. Any amount of expertise would be greatly appreciated.

5 Comments
2024/03/20
09:22 UTC

2

HLSL normal interpolation

So I'm just getting started with DirectX and HLSL, I have an ok grasp of the math but I'm not quite sure about something. I'm trying to start simple, create a grey cube and light it, no textures. We have a Vertex Buffer and an Index Buffer, these are bound to the Input Layout. The vertex data sent to that buffer include color and normal data. I got the normal data by taking each triangle in the triangle list (indices, which are sent to the Index Buffer) and finding its normal using cross products, then get the normal for each vertex by averaging the normals of its adjacent triangles. But unfortunately, each cube face has 2 triangles, and the shaders re-calculate the normal for each triangle by averaging the vertex normals! Now, on a face of the cube, the two triangles have different normals! This is great for rounded objects where interpolation is desired, but for flat objects, it looks wrong. How can I give the triangles sharing a plane (cube face) the correct normals, where they are both the same? HLSL doesn't have 'triangle data' just vertex data and index buffers to build triangles

4 Comments
2024/03/19
16:46 UTC

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