3ds Max Visibility Property not working properly for Railclone objects with V-Ray GPU.

[dennis_chaplin]

Hello,

I'm trying to make an animation where several railclone objects appear and disappear. I was thinking on just animating the 3dsmax visibility property (from 0 to 1 and vice-versa), but this doesn't seem to work when I try to render with VRAY Next. The railclone objects always stay visible, regardless of the visibility property's value. This happens when the railclone object has a "multi/sub-object" material assigned. When a VRay Material is assigned directly, the Railclone object's visibility partially works. In this last case, the object follows the 3dsmax visibility property (disappears if set to 0.0), but the shadow is still there. Are there any solutions out there for this?
Setup: 3ds Max 2018, V-Ray Next, Railcone 4.21
Thank you!

[fixeighted]

This should help
https://forums.chaosgroup.com/forum/...illity-channel

[dennis_chaplin]

The solution above works efficiently for a few objects. However, the scene I'm working with has 60+ different objects appearing and disappearing through time. I believe I would need to create 60+ different materials to achieve this and it doesn't seem too practical.

[fixeighted]

Sure, I understand, though it's one of those situations where it's not a click'n'go solution.
Visibility channel isn't going to do it alone in any case, plus it just is horrible to use, at least in my experience.
Another solution is to matte the various objects, separate the shadows also, then combine and animate them in post.
Cryptomatte could be of real use in this case. At least you have more immediate control and rapid feedback on timing.

[dennis_chaplin]

In this particular animation, objects only appear and disappear at a given frame (think of a timelapse). So, there is no transparency at any given point (and no back-face issue); the objects are either visible or not. I think the Visibility Property is a good way to approach this: keys are either 1 or 0, for visibility. The keys can be copied to multiple objects and just be adjusted. I thought this basic property would be fully implemented under GPU and for railclone objects, but it's not.

I know I can collapse the railclone objects to editable polys and the visibility then works. However, it is important for me to keep the parametric modeling and not add an extra step in the process.