Enivob
Wouldn't you need to create the materials inside a material library instead of the /mat context? Perhaps alter your hou.parent path to point to a Solaris-based node?

hou_parent = hou.node("/stage/materiallibrary1")

Enivob
I'm no Solaris expert, but I think Solaris is built on pathing, so where things are located is highly important.
I altered your code, and it worked to create a material subnet inside a material library on stage. However, the subnet was empty in both test context. Maybe Solaris isn't recognizing it because there is no actual material in the subnet.

asCode()

node.type().name() = "subnet"

cdordelly
Hi!

I haven't checked your code but, maybe you can explore the voptoolutils.py (located inside the python lib on the Houdini installation folder), you will find the code that is used to create the vanilla Karma Material Builder and the others based on subnet, maybe you can compare the code to see if something is missing in your version.

For example, this is the code use to create the Karma Material Builder subnet node:

import voptoolutils
mask = voptoolutils.KARMAMTLX_TAB_MASK
voptoolutils.createMaskedMtlXSubnet(kwargs, 'karmamaterial', mask, 'Karma Material Builder', 'kma')

Of course you will need to explore the functions inside

createMaskedMtlXSubnet()

and so on.

Hope that helps,

hou.node("/path/to/subnet").setMaterialFlag(True)

CrisDoesCG
Ok so for the solution on how to create a Karma Material Builder using Python, there are two ways:

1. Doing it yourself, something like this (sorry for the messy code):

import hou

INHERIT_PARM_EXPRESSION = '''n = hou.pwd()
n_hasFlag = n.isMaterialFlagSet()
i = n.evalParm('inherit_ctrl')
r = 'none'
if i == 1 or (n_hasFlag and i == 2):
    r = 'inherit'
return r'''

destination_path = "/PATH/TO/THE/MATERIAL/DESTINATION"
destination_node = hou.node(destination_path)

subnetNode = destination_node.createNode("subnet","NAME_OF_YOUR_MATERIAL")
subnetNode.moveToGoodPosition()
subnetNode.setMaterialFlag(True)                  

parameters = subnetNode.parmTemplateGroup()

newParm_hidingFolder = hou.FolderParmTemplate("mtlxBuilder","MaterialX Builder",folder_type=hou.folderType.Collapsible)
control_parm_pt = hou.IntParmTemplate('inherit_ctrl','Inherit from Class', 
                    num_components=1, default_value=(2,), 
                    menu_items=(['0','1','2']),
                    menu_labels=(['Never','Always','Material Flag']))


newParam_tabMenu = hou.StringParmTemplate("tabmenumask", "Tab Menu Mask", 1, default_value=["MaterialX parameter constant collect null genericshader subnet subnetconnector suboutput subinput"])
class_path_pt = hou.properties.parmTemplate('vopui', 'shader_referencetype')
class_path_pt.setLabel('Class Arc')
class_path_pt.setDefaultExpressionLanguage((hou.scriptLanguage.Python,))
class_path_pt.setDefaultExpression((INHERIT_PARM_EXPRESSION,))   

ref_type_pt = hou.properties.parmTemplate('vopui', 'shader_baseprimpath')
ref_type_pt.setDefaultValue(['/__class_mtl__/`$OS`'])
ref_type_pt.setLabel('Class Prim Path')               

newParm_hidingFolder.addParmTemplate(newParam_tabMenu)
newParm_hidingFolder.addParmTemplate(control_parm_pt)  
newParm_hidingFolder.addParmTemplate(class_path_pt)    
newParm_hidingFolder.addParmTemplate(ref_type_pt)             

parameters.append(newParm_hidingFolder)
subnetNode.setParmTemplateGroup(parameters)

You will obviously need to delete the nodes that are inside the network, create the outputs and the necessary nodes. But this gives at least a base that will be recognized by Solaris when trying to import it via `sceneimport` node. Also this will give you more control in comparison to



2. Following this video [youtu.be], this works inside a LOP network, but won't work inside any other regual material network. Here is the code:

import hou
import voptoolutils

mask = voptoolutils.KARMAMTLX_TAB_MASK

viewer = hou.ui.paneTabOfType(hou.paneTabType.NetworkEditor)

kwargs = {
    "pane":viewer,
    "autoplace":True
}

voptoolutils.createMaskedMtlxSubnet(kwargs,"karmamaterial",mask,"Karma Material Builder", "kma")

Thanks to u/EconomyAppeal1106 from this thread [www.reddit.com] who pointed me to their video.

import hou
import voptoolutils

mask = voptoolutils.KARMAMTLX_TAB_MASK

sel = hou.selectedNodes()[0]
root = sel.parent()

materialLibrary = sel.createOutputNode("materiallibrary", "MaterialLibrary")
kmaPath = materialLibrary.createNode("subnet", "karmamaterial")
voptoolutils._setupMtlXBuilderSubnet(kmaPath, "karmamaterial", "karmamaterial", mask, "Karma Material Builder", "kma")