Of course, both render engines are very different but I did not expect arnold to show such severe artifacts. I would have expected ray-intersection and displacement to be always computed in worldspace.Ī displaced 1x1x1 unit cube for example in Cinema Standard or Physical Renderer at the orgin and moved 200.000 units off the origin does not exhibit any visible shading artifacts (pictures attached). There are precision artifacts but within acceptable ranges, although more noticable then i would expect at 4000 units for objects 30m large with a camera distance of roughly 0.5 units. Unparenting, scaling and freezing transforms on them leads to more expected results. The precision issues of the asteroid as well as the intersection imprecision on the spaceprobe landed on the asteroid (both are previz versions of the asset) seem to come from the fact that they are scaled in object space.
I've since checked the scene and noticed that several transforms in the newest version of the shot are buffered in groups that have a scale of 15 while the asteroid (in the other thread) itself is scaled 1/15 to keep its world space size. However, we're getting almost as extreme displacement variations at 4000 units off the origin. The cube at 200.000 is, frankly, an exaggerated example and you're right that we should expect some precision loss. Known Problem? Any pointers to a possible solution?Īs mentioned here we're aware of float precision and have moved objects back to the origin during long takes before (mental ray, vray, c4d, arnold 4). We could not yet test any other system configurations. Testing was done on Win 10 machines running Maya 2018.6 and arnold 3.3.0. We're discussing downgrading arnold currently. I'm not usually one to cry "bug!" the first time there's an issue, but I'm pretty sure this worked flawlessly before, isn't our fault and might be a pretty serious bug. Screenshots and file attached.Īs we're working on a 360° 10.000 frame sequence theres no way for me to conventiently move the object to around world origin as a workaround, and short of baking the displacement into geo half a day of troubleshooting did not present any viable solution. Object space tranforms exhibit the same behaviour and this seems to be a world-space issue. The object gets progressively more destroyed the farther it is moved from the origin. The bahviour is reproducible with a simple cube and a camera parented to it. We noticed this behaviour in a scene containing several asteroids which are merely moved to roughly world 0,4000,0 units.
Everything seems to be fine at world origin, however as soon as we move the object displacement gets progressively less detailed and introduces severe shading artifacts. Displacement seems to dramatically loose precision with translation of the displaced object in worldspace. We just noticed a displacement issue with Mtoa 3.3.0 and Maya 2018.6 which currently is an absolute showstopper for a shot we're working on as it will be severly inconvenient to work-around.
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