Has something changed to maxscript access of the VrayMultiSubTex between vray 3.40.02 & 3.60.01

[Y.Adam]

We have a maxscript for submitting things to the renderfarm which does all sorts of things, one of which is creating a VrayMultSubTex with a buinch of Paremeters.
It works fine in 3ds Max 2015 with Vray 3.40.02 but in 3ds Max 2018 with Vray 3.60.01 I get an error.

this is the line that's throwing the error.

refalpha = (VRayCompTex name:"reflectie alpha" sourceA:wcol sourceB:refocc operator:3)
refglas = (VRayMultiSubTex name:"reflectiemask glas" texmap_num:1 from_id:1 default_color:(color 0 0 0) color_1:(color 0 0 0) id_1:1 texmap_1:refalpha texmap_on_1:true)

this is the error it's throwing:

-- Error occurred in anonymous codeblock; filename: ; position: 448; line: 8
-- Runtime error: Property is read-only: texmap_num
-- MAXScript callstack:
--    thread data: threadID:24220
--    ------------------------------------------------------
--    [stack level: 0]
--    In anonymous codeblock; filename: ; position: 501; line: 8
--        Locals:
--            refalpha: undefined
--        Externals:
--    ------------------------------------------------------
--    [stack level: 1]
--    called from top-level

was this parameter not read-only in previous versions ? what happened ?
I uncommented it and it appears to work, but why would this work previously ?

[alexander.kazandzhiev]

Hello,

As long as I remember it's been a read-only property nearly from the beginning, as the logic behind the texmap number is a bit more complex, you can find a description here: https://docs.chaosgroup.com/display/VRAY3MAX/Multi+Sub-Object+Map+%7C+VRayMultiSubTex#MultiSub-ObjectMap|VRayMultiSubTex-MaxScriptAccess

Best regards,
Alexander