3ds Max morph not exporting correctly using bend and FFD lattice modifiers

[PatrickRyanMS]

This morph is a simple bend of a plane to simulate a piece of paper curling. The morph was done in both Maya and Max where the plane bends up and down. As you can see in the video below, the Maya version correctly bends the plane up and down as authored using a bend deformer. The Max version us using a bend modifier to bend the plane in one direction and an FFD 4x4x4 modifier to bend in the other direction to determine if the issue is with the particular modifier. In both cases, the morph moves the plane translation as well as always bending the plane in the same direction causing a double transform if both influences are set to 1.0. It doesn't matter which modifier is added to which morph, they both deform the mesh incorrectly in the same direction.

bendMorphs_mayaVmax.mp4

The pivot for the bend modifier in Max is set to the edge of the plane to get the correct deformation. I also did the same experiment with the pivot in the center as created and added bend modifiers. While the origin of the bend correctly moves to the center of the plane, both bend modifiers deform the mesh in the same way when exported to glTF, even though they were authored to bend in opposite directions. The notable change is that there is no translation of the mesh in the morph like there is when the pivot is moved to the edge of the plane, suggesting that part of the issue relates to the mesh pivot.

Attached are sample Max and Maya files with the bend morphs set up as well as gltf files exported from Max 2023 and Maya 2023 using exporter v20221031.2. Additionally there is a Max 2023 file of the bend morph without moving the pivot from the center for comparison. The morph deformations are still wrong on export, but there is no translation during the morph.

max_morphBug.zip