Questions tagged [shadow]
Shadows cast by objects in front of lights, whether raytraced, shadow maps, shadow volumes, or any other technique
48
questions
0
votes
0answers
28 views
Shadow volume/stencil shadow penumbra rendering
While I am not looking for a method to render soft stencil shadows, I am trying to achieve hard shadow rendering that is extended to include the penumbra regions of a shadow for omni-directional ...
1
vote
0answers
46 views
Shadow Bug when Raytracing Triangles
Spheres with shadows work fine. But when I try to include triangles with shadows, they are shaded incorrectly (i.e completely black):
But when I disable shadows Blinn shading on triangles work fine (...
3
votes
0answers
42 views
ray racing (Whitted) bad shadow on far objects (artifact)
situation:
I've implemented a Whitted style ray tracing in C. Everything appear to works except the shadow cast by small object on big far objects
The problem :
red sphere have radius 0.5
orange ...
0
votes
1answer
50 views
What can be the cause of some strange ray shadows artefacts on a perfectly flat surface?
First of all I have to say that I am really new in the world of Computer Graphics. I apologise if some of my questions may appear trivial.
I am currently using a non-commercial ray tracing and ...
3
votes
0answers
244 views
How to implement PCSS correctly?
I'm trying to implement PCSS in OpenGL/GLSL, but I have problems understanding the details especially the conversions between the coordinate spaces. The existing implementations are so different from ...
1
vote
1answer
49 views
How can I account for specular interactions in shadow rays?
I've been working through PBRT, implementing my own version of it in Rust. Right now I'm working on shadow rays, and it looks like pbrt doesn't do anything to account for specular behavior, and treats ...
1
vote
3answers
97 views
Silhouette below 3D model
There are some 3D applications which can cast shadow or silhouette below 3D models. They render pretty fast and smooth. I wonder what kind of technology is the standard procedure to get 3D model ...
1
vote
1answer
88 views
Too soft shadows from multiple suns
I want to render the transient shadows due to the sunlight over a day in one image. So I placed all the suns, as directional light, in the scene. However the shadows in the rendered image(a raytraced ...
1
vote
1answer
268 views
Retrieve real distance from depth buffer for shadow ray (vulkan hybrid rendering)
I'm trying to implement an hybrid renderer based on Vulkan extension VK_NV_ray_tracing. Basically, the rasterizer compute the albedo and depth map of the scene. Then I try to compute the distance from ...
2
votes
1answer
291 views
GL_DEPTH_CLAMP has no effect (reverse z)
In an effort to improve cascaded shadow maps, I have looked into using GL_DEPTH_CLAMP and moving the near and far plane just around the actual view frustum instead of the global bounding box. But the ...
1
vote
1answer
153 views
ShadowMap peter-panning and wrong direction
I am creating Forward-Rendering DX11 engine and I have some troubles with shadow-mapping algorithm as it doesn't work as supposed.
As you can see - shadow is peter-panning and looks totally not ...
2
votes
1answer
181 views
R16_FLOAT, SampleCmp and CheckFormatSupport
I want to use PCF shadow map on my d3d11 app. My shadow map is an R16_FLOAT texture. When I use SampleCmpLevelZero it didn't give a correct result. After enabling debug layer, it shows:
The Shader ...
0
votes
0answers
191 views
Changing coordinate system from texelFetch to textureLod is breaking the algebra
I have a scene rendered using texelFetch() and I am trying to modify the shader to use textureLod() instead.
This is the image generated with texelFetch:
When I try to change the shader to use ...
1
vote
0answers
220 views
Voxel cone tracing artifacts (what causes them and how to solve them)?
I am trying to generate soft shadows using voxel cone tracing.
Which gives me the next images:
In the first image you can see an artifact of a sequence of horizontal shadows alternating with ...
1
vote
0answers
269 views
Handling shadow acne for dynamic surfaces
My path-tracer is generally fine and gives good output for regular test scenes, but I've noticed dense fireflies and dark speckles over fractal surfaces. The noise disappears if I render without light ...
0
votes
1answer
511 views
How to use shadow mapping and deferred rendering to create a large amount of lights?
Ok so I am trying to understand how to combine these 2 techniques and I am failing.
The main goal is to reach the O(lights+fragments) complexity of deferred rendering, instead of O(lights*fragments) ...
5
votes
2answers
406 views
How did the hard, accurate shadows, work in early 3d (2000 - 2004) games?
I've been hunting around the internet for a while now, and I can't find anything about the specific shadow technique that I'm looking for.
I can only recall one game in particular that used it, and I ...
2
votes
0answers
81 views
How can you efficiently get the last element occluding light when rendering shadows?
A long time ago I made an application that used volumetric rendering and I developed some shadowing equations that I felt very happy with, since they have pretty good results.
For these equations to ...
4
votes
1answer
427 views
Experimental real-time shadowing techniques?
The three most popular shadowing techniques for real time applications are:
Shadow maps
Advantages:
Fast
"Simple"
Disadvantages:
Numerical limitations lead to artifacts and jaggy shadows
You ...
2
votes
1answer
2k views
Path tracing with Next event estimation and area lights auto occlusion
I am working my way through my first path tracer and I am currently designing how to deal with area lights. I have two questions:
Each object in my scene can have a Light attached to it, this is how ...
1
vote
1answer
1k views
OpenGL: Rendering 2D shadows
I've been working on a 2d shadow system for a school project, using this method to generate visibility polygons. However, I'm having issues figuring out how to draw those visibility polygons in a way ...
2
votes
1answer
202 views
DX9 Shadow map PCF issue
I am trying to do simple PCF with Unity but I am facing some issues and I don't know where they come from. If anybody has an idea...
Here are two examples
...
5
votes
0answers
787 views
Cascaded shadow maps. Seams between cascades
I implemented cascaded shadow maps, where shadow maps for each cascade is rendered to one canvas:
The light projections for each cascade are calculated from the bounding spheres of camera sub-...
5
votes
0answers
225 views
Dual paraboloid shadow texture edge seams
I implemented dual paraboloid shadows for point lights. The goal was to reduce the number of shadow passes. Also the target is GLES3.0 so no layered rendering is available. The shadows work, and ...
1
vote
0answers
41 views
What could cause realtime lighting within a viewport to be calculated on the wrong part of the screen?
(I initially posted this in a section that is less suited for the particular issue, oops)
I'm having this issue on some of my client's computers (this is for a Unity asset) that I cannot reproduce on ...
3
votes
1answer
517 views
Tracing shadow rays in a scene with mirrors
In my real time ray tracer, I shoot primary rays from the eye, and at hit points, I trace to a single light source to determine if the object is shadowed or lit.
Pretty straightforward stuff so far.
...
6
votes
1answer
2k views
Ray Tracing Shadows: The Shadow Line Artifact
By using smooth shading (i.e. interpolation of normals), an object can have a smooth look despite low polygon count. A nasty artifact that can happen when casting shadow rays is the Shadow Line ...
5
votes
3answers
204 views
In forward rendering what's the go to technique to smooth out rigid shadow due to low resolution shadowmap texture?
I am building my own graphic engine.
My depth texture is significantly smaller than that of the screen.
The low resolution depth map results in rigid shadow like this...
I am sure this is a common ...
3
votes
1answer
312 views
How to send shadow rays to window light source with glazing
For rendering an indoor scene where light source is skylight coming in through
the window opening, one can consider the window polyline as the light
source, with the sky distribution, in direct ...
3
votes
3answers
550 views
Sending shadow rays to the sun
How is sun modelled for ray tracing rendering? Is it part of the scene, like a
sphere with a centre in some far location or it is just considered as a point?
Also regarding sending shadow rays to the ...
3
votes
1answer
148 views
What is this shadow mapping error called?
I have been following a tutorial, shadow mapping works more or less as expected except sometimes the shadow projects completely weirdly on nearby walls. This isn't sampling outside the lightmap ...
5
votes
0answers
906 views
Percentage-closer Soft Shadows implementation
I am trying to implement the Percentage-closer Soft Shadows (PCSS) from NVidia inside Unity but I am facing some issue and I don't know where they come from and then, I do not know how to solve them......
4
votes
1answer
670 views
Exponential shadow maps sampling with PCF for sampler2DShadow instead of sampler2D
I am trying to make use of free hardware PCF sampling with sampler2DShadow and extend it to more samples.
So far I am sampling shadow map (...
7
votes
2answers
3k views
Better Shadow Mapping Techniques
Currently I have basic shadow mapping setup in my engine. I am currently trying to implement something more realistic like PCSS (percentage closer soft shadows), to get a more physically accurate ...
0
votes
1answer
888 views
What are some new Real-Time Graphics Rendering Techniques to get closer to real life? [closed]
So recently after implementing PBR in my engine, I was wondering what are some new & old Rendering Techniques that people are implementing and researching to get Real Time Graphics closer to what ...
8
votes
1answer
192 views
searching for acceptable quality shadow mapping techniques
Recently while searching of solving the shadow acne problem of traditional shadow mapping I implemented exponential shadow maps. It did the trick (no acne at all) but at the same time introduced other ...
5
votes
2answers
2k views
What is the difference between shading and shadowing?
Shading and shadowing are often mentioned in how to create realistic 3D graphics, but the distinction is not clear. Are both responsible for the generation of shadows, or do they refer to the same ...
3
votes
1answer
134 views
Components that can be used for 3d shadow analysis, sunhours of surfaces throughout the year in a 3d model?
I want to develop a component for 3d shadow analysis of 3d city model. I decided to use ray tracing for this purpose. For every time step (for sun's dynamic position during the year) rays will be sent ...
8
votes
1answer
479 views
How does the rendering equation incorporate shadowing
This is how the rendering equation is written in the textbook
$$L(p,\omega) = L_e(p,\omega) + \int f(p,\omega_i,\omega) \, L(p*,-\omega_i)\cos \theta \, d\omega_i$$
which component of this equation ...
2
votes
2answers
1k views
How are hard and soft shadows cast?
I have been studying computer graphics, from the book Fundamentals of Computer Graphic (but the third edition), and I lastly read about texture mapping and shadow maps. Though, I didn't exactly ...
5
votes
1answer
891 views
How to compensate low amount of rays reaching the light in a Path Tracer
I am trying to implement for research purposes a path tracer, but so far but results are not so good and I will explain you why. The general idea before getting to the code:
I am working on paths ...
4
votes
2answers
686 views
Path tracer not rendering shadows
I am trying to implement for research purposes a gradient-domain path tracer. In order to achieve this step I first need a working Path tracer. I have been creating one so far but results are wrong ...
7
votes
2answers
841 views
Raytracing Problem - Casting Shadows
So I was tasked to create a model of the Cornell Box. I've managed to do everything up until casting shadows, in which case some shadows are cast when there should not be any. Here are pictures of ...
2
votes
0answers
137 views
Shadow Mapping Errors
I recently started to create a shadow mapping system in OpenTK.
I ran into a problem: The depthtexture is always completly white -> no depth. Even if the color from the shader is changed (I know it ...
6
votes
1answer
5k views
Shadow rays in Raytracing
After spending a few days making very little headway with a simple Raytracing program that implements Phong illumination (with shadows and no attenuation), I'm convinced I've made a logic error that I'...
3
votes
2answers
119 views
Storing shadow data
Given a 3D space and a light source, I use ray casting to determine the shadows generated in the scene. If I'm to store the shadow data (boundary of the shadow, object which cast the shadow, etc.) ...
8
votes
1answer
1k views
Shadow Mapping artefacts
I've been playing around with shadow mapping in OpenGL using depth textures. The depth texture is fine and I can map it onto the scene but I have some strange artefacts on the back of the object:
My ...
7
votes
2answers
2k views
Am I missing something for ambient occlusion?
I'm trying to implement ambient occlusion in Python 3 and I'm seeing shadows beneath my reflective spheres but they seem very faint. I'm not sure if that means I've missed something, or if I just have ...
