Questions tagged [pdf]
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Confusion about PDF defined in solid angle / area measure
When using MIS, we always want to express the PDF value in a unified measure in order not to render the ratio between them meaningless. Yet when I read through chapter 16 of PBR-book, I got confused ...
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Integral over cosine weighted sphere cap/cone
I'm not sure I have the right terminology, but in rendering it can be useful to draw cosine weighted samples from a hemisphere. In this case the integral (over the weights) is Pi.
Now I don´t want to ...
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Ambient occlusion with cosine-weighted sampling looks different than uniform sampling
I’m implementing a basic ambient-occlusion thing and tried to add cosine-weighted sampling but the results are looking distinctly different than with uniform sampling, even with large sample counts. I’...
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PDF for sampling emissive meshes for NEE/MIS
I'm writing a Monte Carlo path tracer, and I'm trying to allow any mesh to be an emitter, but I'm not entirely sure about the probabilities to use when I sample them.
Right now, my algorithm for light ...
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How can I step through a pdf file while maintaining a fixed viewport for each page?
I have developed some software that generates a pdf file for visualizing air traffic. Each page shows a plan view of the traffic at a point in time, with a small time step (e.g., 20 seconds) from one ...
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How can I make the simplest physically based mixed specular-diffuse BRDF (and how to properly sample it)?
I am having troubles making a BRDF that has both specular and diffuse part. Each one is weighted by a coefficient and the sum of coefficients should be equal to one.
I want this layered BRDF to be the ...
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How to find the importance sampling function for a specified BRDF?
I am currently working on BRDF and their associated probability density functions (PDF) in order to importance-sample them. It is really hard for me to find the correct way to compute the PDF of a ...
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Do scanners and scanning software compensate and enhance blurry sources?
I received a pdf from a client containing several invoices. Upon further inspecting, some lines on the invoice seem digitally produced. When I tried selecting the page, copying it then pasting it on ...
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Why isn't the 'Map Colors' fixup changing text colors?
I saw this question some where, I think Reddit, but I can't find it. I have same issue.
Please see the screenshot beneath. I've uploaded the PDF to mega.nz I'm using Adobe Acrobat Pro DC Version 2019....
user13771
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An equation about PDFs and differentials in the book of pbrt-v3
Why does the equation at the bottom of the following page hold?
http://www.pbr-book.org/3ed-2018/Monte_Carlo_Integration/Transforming_between_Distributions.html
$p(\theta,\phi)d\theta d\phi=p(\omega)...
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