VrayMultiSub - MASH - vray proxy - twosided - randomness bucket errors

[ali_cgi]

Hi I'm assuming this isn't a mash problem, I'm getting severe render bucket differences when using the new random hue/ sat features in the vraymultisub texture node.
All render buckets appear random to be picking random colours.
Im distributing vrayproxys with two-sided vray shaders "plants" via a MASH setup. Maya 2020 vray5 both the latest service packs
If I switch the multisub back to object id the problem is resolved, presuming as all are then the same ID so therefore no randomisation.
This happens with both, render id and instance-id randomisation. Havnt tried others but renders fine once in object id mode
Easy to reproduce just follow above setup with some 2sided plants.
I went through every vray setting to debug this as thought it was a render setting problem. So I'm confident there's either a problem with multisub or some incompatibility with mash.
Please help urgent

[Dimitrina.Milanova]

Hello there,

Can you please attach a scene, with which you are able to reproduce this problem, so I can have further look into it.

Kind Regards,
Dimitrina Milanova

[ali_cgi]

Hi yes do you have an email address I can send to, it is not something I can share publically and may be quite large with linked assets

[Dimitrina.Milanova]

Hello again,

You can send the scene to this email: dimitrina.milanova@chaosgroup.com

Kind Regards,
Dimitrina Milanova

[yolov]

Hey ali_cgi , We got the scene, but I'm not quite sure I see the problem.
Can you post an image of what the problem looks like, so we're sure we're seeing the same thing?

There's a few materials using MultiSubTex in different modes and so far I have a few observations:
One of them is in Texture Switch mode with a simple value (2) selected, which means that all objects with this texture will receive texture 2 from its list.
There's another one in Texture switch mode, where a floatConstant passes a value of 8, which means all objects with this MultiSubTex will receive texture 8 from its list.
Is this expected?

Then there's 3 more MultiSubTex textures in "Object ID" mode. In this mode the obejcts with the texture are expected to have an Object ID assigned, but I can't find any Object IDs on any of the objects. Also this mode just reads the IDs and assigns the textures from the MultiSubTex list, without any randomization of hue/sat/gamma.
The modes that allow hue/sat/gamma randomization are the "Random By ..." modes, have you tried using Random By Node Name?

In any case, an image where we can see the problem will help us further look into the scene.
Also if you can share more details about what the expected result is, that would be great.

[ali_cgi]

Hey, I'll try and package up a simplified scene at some point, those constants and texture switches don't relate to the problem you could just apply a basic vrayshader to the floor,. It's just the plants, 2sided materials, the problem arises when the multisub tex are in render id or instance id mode with values in hue, sat, gamma randomness, if you then bucket render the plants you will get random differences per bucket, I have resolved this issue by not using vrayproxies within mash, just the regular meshes/ shaders, so pretty sure there's a vray / mash incompatability going on or a bug.