#cycles render engine

A couple or renders of my BMX 3d model available on the Sketchfab store!

A couple or renders of the car 3d model available on the Sketchfab store!

[ID: Two sets of image comparisons, testing three Pixel Filter width values on two camera angles of a 3D render. The consistent information is listed across the bottom of each comparison, including the credit:

Models, textures, and tests by CJ Gladback Pixel Filter Type: Blackman-Harris Cycles Render Engine, Blender 4.0.2 512 samples denoised and mixed with original in compositing

The compositor nodes overlay the images to the right of this information; the rendered image is denoised using its normal and albedo passes, mixed with a factor of 0.8 over the original image, denoised again, and mixed over the original image with a factor of 0.975 for the final composite.

Both comparison shots feature a green plaid blanket in golden hour lighting, folded around the shaft of a cane and fastened with a leather belt. The first shot is closer up and from above, focused on the curved folds of the blanket where they bend around the cane. The second is from a glancing angle to the top of the blanket and further away. Each image compares a pixel filter width of 0.5 px, 1.5 px, and 2.5 px. In both, there's a strong wave-like pattern called moire in the 0.5 px example, most visible where the weave of the fabric is compressed, either from bending away from the camera or shrinking into the distance, on the folded blanket edges and, in the oblique shot, on the top of each blanket layer. The 1.5 px example nearly eliminates the moire, only a ghost of curves cutting through the woven patten where the 0.5 px distortion was most extreme. The 2.5 px examples are both very soft, completely eliminating the moire but also smoothing the details of other materials in the shot. End ID]

Yesterday I learned what the Pixel Filter in Cycles does! It would make sense if I had heard of it (I've followed plenty of people trying to create 3D pixel art and the automatic antialiasing that the filter represents would have to affect that). But I don't recall ever touching that set of parameters in the Film render settings before.

That changed yesterday while I was being productive in anything but my handful of equally-high-priority items and happened to open Blender Artists to check their support section for questions I could answer. And lo! There was one about Blender seeming to post-process renders to the detriment of a fabric texture, even when the artist had requested no denoising nor other compositing functions. I've had my share of suspected glitches when Blender's image viewer just doesn't handle an irregular zoom well, but the artist confirmed it had the same issue when viewed outside the app. How bizarre! Obviously it required some research.

Thankfully, from photography, monitor troubleshooting, and more™ I'm quite familiar with the term moire (shoutout to my once-classmate Hannah Paz-Westbrook who's done whole series' of paintings exploring it). So I was outfitted with a helpfully specific search term that turned up a past struggle with moire on a dense pattern rendered in Cycles -- and their solution was to render a larger image and scale down and widen the "pixel filter." I had to look up where that even was and in the process found an old discussion on what it does.

But the new knowledge wasn't complete until I could do a few tests to see how it could be applied...and once you have your tests and images are nicely labeled for your own reference, obviously you gotta publish them. So behold!