Issue with VRayBlendMtl - Interactive Rendering Freezing Object Animation

[szimano]

Hello,

We have encountered an issue with VRayBlendMtl, which is demonstrated in the attached video. Additionally, I am providing the scene file for reference.

The scene consists of an object linked to helpers, with two keyframes: a 360-degree rotation (the same issue occurs when keyframes are directly applied to the object).

The problem arises during Interactive Rendering—when moving along the timeline, the object and helpers stop animating, despite the keyframes still being present. The issue is best illustrated in the attached video.

This behavior occurs most often when any node is plugged into the "blend" slot.

Software versions:

• 3ds Max 2025.3
• V-Ray 7.00.04

Any insights or potential workarounds would be greatly appreciated.

Best regards,
Łukasz Szymański / MILLARC

scene
video

The material is not complicated, a simple blend.

[hermit.crab]

Thanks for the provided scene. Odd issue. It seems this is 3ds max related since I managed to reproduce it with both Arnold and Scanline. It happens when using the native Falloff map with a Falloff Direction, either Local XYZ or World XYZ, for a shader's reflections (tried Physical Material with Arnold and Standard with Scanline). With V-Ray, it also happens with a VRayMtl. The good news is that there's an easy workaround - instead of the native Falloff, use the VRayPluginNodeTex to load the "TexFalloff" plugin, where all native falloff settings are present.