Aside from simplifying/streamlining the example above I’ve since replaced TransformPosition with TransformVector equivalent as per compliance with the TransformPosition deprecation status due to precision concerns.
This node is deprecated due to major precision problems when used to derive world pos away from the origin! Use the WorldPosition node instead.
Whatever I try, offsetting the pivot leads to precision issues resulting in the black shimmer appearing.
There is also already an open ticket around this issue (UE-42379): Unreal Engine Issues and Bug Tracker (UE-42379)
So I’m building some wind materials and using RotateAboutAxis to convey realistic foliage deformation. However, whenever I try to offset the PivotPoint (aka local offset transformed to world space) a black shimmer appears flickering all over the mesh. Is this a precision issue ? It only seems to work when inputting world space Actor position without any modifications to it local → world space.
In an unrelated sidenote, RotateAboutWorldAxis_cheap is broken on the Y-axis, so unusable ?
Here’s a fix for Y being broken with RotateAboutWorldAxis_cheap, in the process I also fixed the flipped X rotation. So now everything rotates in the correct direction on all axis.
As a side note, there is nothing stopping you to input local position and local space pivot such as (0,0,0) to rotate in local space. Just remember to transform the result to world space before inputting in WorldPositionOffset.
So the name “RotateAboutWorldAxis_cheap” might be pigeonholing it a bit.
This seems to be a shader compilation / driver issue ? It does not appear on a AMD 5700XT but can sometimes appear on a Nvidia RTX 3070. (tested on 2 different RTX 3070 cards)
