The Past 4 Days (Patreon)

First of all, I want to apologize for missing out on my goal for page 5 landing on monday. TLDR; rendering technical issues have been a nightmare, and the problem was so simple it makes me physically enraged. Keep reading and I'll tell you why...

I create my backgrounds in Blender, then use the supported plugin and Renderman server to make final renders. This has been relatively trouble free, and I've been using it for several months in planning for the "Closer" comic as well as rendering backgrounds for the Football Champs pics. Renders look gorgeous, materials and lights are a dream to work with, and render speed is comparable or better than most other options I've played with apart from Redshift.

Version 21.3 was released last week, so naturally I updated, as well as updating the plugin that integrates it into Blender. All seemed to be working fine, except I noticed late Sunday night that my renders weren't de-noising. This is a process that uses 4 different passes combined in an algorithm to get rid of visible noise from the picture. without it, renders could easily take me 10 hours to render per frame. De-noising wasn't working anymore, leaving the image crusty and noisy, and there was no real information as to why.

This is a maddening thing to troubleshoot. De-noising is the last step to a full render, so it would take anywhere from 10 minutes to an hour per attempt to see if what I did worked or not. It wasn't consistent either. My scene would fail, but a simple cube rendered at any resolution would not.

I tried making duplicate scenes, empty scenes and moving the objects in one by one, linking the objects into the scene as references, every possible render setting and integrator, render passes, nothing worked. I even re-made the scene in Cycles render engine, which required reconstructing all of the materials and lights and using an experimental build of the software, but that looked noticeably worse than Renderman, so I had to scrap it. I wasn't going to deal with inferior render quality for this project, or any project moving forward.

So what was the issue?

I installed the server on my PC and tried out GPU de-noising... which failed, but at least it showed me a partially de-noised image. It was putting little black boxes all over the center rug. What's so different about the center rug... Oh my god. It has an Adobe RGB color space, and Renderman's linearize conversion expects sRGB color space. Certain pixels in the rug fell outside of legal 0 to 1 floating point linear color. This rendered, but the de-noiser got confused by the values in the diffuse coefficient pass and would either ignore the pixels or fail completely if the rug was visible. (hint; the rug is almost always visible in this page's panels)

Right now I'm re-rendering the cameras for the panels, and will be doing the final drawings and inking tomorrow (thursday) to hopefully finish this page by Friday. The setback means I only get one page done this week, but at least I figured it out. And if you've read this far then I commend you for your dedication.