V-Ray Script Access - Can I even do this?

[charlie_peckar]

Hello,

I'm trying to write a python script to perform some repetitive actions, but I am struggling with the V-Ray Script Access Documentation (https://docs.chaos.com/display/VRHIN...+Script+Access).

I'd like to perform the following actions for each item in a list of material names:

1. Create a new material duplicated from a template material
2. Rename the new material
3. Swap it's diffuse bitmap for a new bitmap from a list

Is this possible with the tools provided by Chaos?

[nikolay.bakalov]

Hi,

In short:
1) Yes
2) Yes
3) Yes

Consider that you have a template V-Ray material already existing


Since every V-Ray material has a Rhino material table entry, you all non V-Ray changes using a regular Rhino API calls.
Afterwards you use V-Ray API calls to take care of the V-Ray specific materials

Here is what you need to do.

import Rhino
import rhVRay as vray

mtlTable = Rhino.RhinoDoc.ActiveDoc.RenderMaterials
templateMtl = mtlTable[0]

# make copy of the template material, and change its name.
newMat = templateMtl.MakeCopy()
newMat.Name = "/MyNewMat"

# Add the new material to the material table
mtlTable.Add(newMat)

# Modify V-Ray properties - e.g. change the diffuse texture bitmap
with vray.Scene.Transaction() as f:
    vray.Scene.Plugin("/MyNewMat/VRay Mtl/Bitmap/Bitmap").file = r"D:\y5.png"​

And here is the result if you run the script

[charlie_peckar]

Thank you Nikolay! This is very helpful and I will go this route next time

This time the solution I found (with my limited scripting knowledge) was to manipulate .vrmat files as they are saved in plain text format. Your solution makes much more sense!

[nikolay.bakalov]

Manipulating .vrmats is also an option. There is an API for that as well, so you do mot need to parse XML files, or have certain knowledge about the format.

[charlie_peckar]

Can you point me towards the documentation for that API please?

[nikolay.bakalov]

You can check the VRay::Internal::StructuredVRMat class in the AppSDK.
There is no official documentation, but the API is fairly simple to use

[charlie_peckar]

Hey Nikolay, I'm trying to use the AppSDK in RhinoPython, but i seem to be getting this error message. Am I doing something wrong?

RhinoPython runs ironpython 2.7.12. Is that a problem?

imput:

import vray

output:

Message: cannot import vray from python27

Traceback:
  line 37, in import_module, "C:\Program Files\Rhino 7\Plug-ins\IronPython\Lib\importlib\__init__.py"
  line 17, in <module>, "C:\Program Files\Chaos Group\V-Ray\AppSDK\python\vray.py"
  line 1, in <module>, "C:\Users\charlie\AppData\Local\Temp\TempScript.py"​

[nikolay.bakalov]

that won't work. RhinoPython is IronPython 2.7, and appsdk is implemented on CPuthon

it should work with Rhino 8 though. They switched to CPython 3.9 there