Not about the node editor specifically, but there are some example Python Octane scripts in this thread:
https://render.otoy.com/forum/viewtopic.php?f=30&t=43086&p=208809&hilit=python#p208809
Also, here is a script I wrote to convert Octane Materials to native Cinema 4D ones, mainly so the textures are picked up by FBX export to Unreal. It shows you examples of some of the Octane nodes etc. It's a little crude, but every line is commented. When it comes to finding out the ID's for different Octane nodes, you can drag them into the console & then add '.GetType()' & hit enter - that will give you the numerical ID for that Octane node.
"""
OctaneToC4d
v0.1
Written by Graeme McDougall for Painting Practice
Copyright: Painting Practice (www.paintingpractice.com)
Written for Cinema 4d R20.057
Name-US:OctaneToC4d
Description-US:Converts selected Octane materials to Cinema 4d materials, as best as possible
"""
import c4d
from c4d import documents
ID_OCTANE_MATERIAL = 1029501 #Here we define more readable IDs for any integer IDs we are using
ID_OCTANE_IMAGE_TEXTURE = 1029508 #To make our code more readable
ID_OCTANE_COLORCORRECTION = 1029512
ID_OCTANE_INVERT_TEXTURE = 1029514
ID_OCTANE_MULTIPLY_TEXTURE = 1029516
ID_OCTANE_MIXTEXTURE = 1029505
mainLayerId = 526336
def CheckSelection(doc, mats): #Checks selection & returns a list of only the Octane materials
oct_mats = [] #Create an empty list, to later store any Octane materials
if mats: #If there are any materials selected...
count = len(mats) #...get how many
for i in range(count): #for each one...
if mats[i].GetType() == ID_OCTANE_MATERIAL: #...if it's an Octane material...
oct_mats.append(mats[i]) #...add it to our list of Octane materials
return oct_mats #Return the list of Ocatne mats
def GetTexture(doc, oct_mat, channel): #Gets a filename from a particular channel of an Octane mat
image_name = None #Create an empty variable to store the image name
image_shader = oct_mat[channel] #Check the texture link & load shader in variable image_tex
if image_shader: #If one is found...
shader_type = image_shader.GetType() #...get it's type
if shader_type == ID_OCTANE_MULTIPLY_TEXTURE: #If it's a multiply shader...
image_shader = image_shader[c4d.MULTIPLY_TEXTURE1] #Get the first shader in it
if image_shader: #If we found a shader of some sort
shader_type = image_shader.GetType() #Load it's type into the tex_type variable
if shader_type == ID_OCTANE_MIXTEXTURE: #If it's a mix shader...
image_shader = image_shader[c4d.MIXTEX_TEXTURE1_LNK] #Get the first shader in it
if image_shader: #If we found a shader of some sort
shader_type = image_shader.GetType() #Load it's type into the tex_type variable
if shader_type == ID_OCTANE_COLORCORRECTION: #If it's a colour correction shader
image_shader = image_shader[c4d.COLORCOR_TEXTURE_LNK] #Get the texture in it's texture link & replace the image_tex var
if image_shader: #If we found a shader of some sort
shader_type = image_shader.GetType() #Load it's type into the tex_type variable
if shader_type == ID_OCTANE_INVERT_TEXTURE: #If it's an invert shader
image_shader = image_shader[c4d.INVERT_TEXTURE] #Get the texture in it's texture link & replace the image_tex var
if image_shader: #If we found a shader of some sort
shader_type = image_shader.GetType() #Get it's type
if shader_type == ID_OCTANE_IMAGE_TEXTURE: #If after checking all this, we have an image texture shader..
image_name = image_shader[c4d.IMAGETEXTURE_FILE] #Read the filename into the image_link variable
print image_name
return image_name #Return the filename, if found
def ReAssign(doc, oct_mat, c4d_mat): #Assigns the new Cinema 4D material to the texture tags
obj_link = oct_mat[c4d.ID_MATERIALASSIGNMENTS] #Get the link list for the Octane Material's assignment
link_count = obj_link.GetObjectCount() #Get how many objects are in the link list
for i in range(link_count): #For each of them...
tex_tag = obj_link.ObjectFromIndex(doc, i) #Get the texture tag
doc.AddUndo(c4d.UNDOTYPE_CHANGE, tex_tag) #Add an undo for the tex tag change
tex_tag[c4d.TEXTURETAG_MATERIAL] = c4d_mat #Replace the Octane Material with the Cinema 4D material
tex_tag.Message(c4d.MSG_CHANGE) #update the tex tag
def RebuildMats(doc, oct_mats): #Rebuilds each Octane material as a Cinema 4D material
c4d_mats = [] #Create an empty list where we store our new Cinema 4D mats
count = len(oct_mats) #Get how many Octane mats we have
for i in range(count): #For each one...
oct_mat = oct_mats[i] #Read the Octane Material into the variable oct_mat
c4d_mat = c4d.BaseMaterial(c4d.Mmaterial) #Create a new Cinema 4D material
name = oct_mat[c4d.ID_BASELIST_NAME] #Read the Material's name from the Octane mat...
c4d_mat[c4d.ID_BASELIST_NAME] = name #...and name the c4d material the same
diff_file = GetTexture(doc, oct_mat, c4d.OCT_MATERIAL_DIFFUSE_LINK) #Get the texure filename from the diffuse channel
if diff_file: #If we did find a texrure filename...
diff_shader = c4d.BaseShader(c4d.Xbitmap) #...create a new empty bitmap shader...
diff_shader[c4d.BITMAPSHADER_FILENAME] = diff_file #...and load the filename in there
c4d_mat[c4d.MATERIAL_COLOR_SHADER] = diff_shader #Assign the bitmap shader to the material's colour channel...
c4d_mat.InsertShader(diff_shader) #...and insert it into the material
opac_file = GetTexture(doc, oct_mat, c4d.OCT_MATERIAL_OPACITY_LINK) #Get the texture filename from the opacity channel
if opac_file: #If we found one...
opac_shader = c4d.BaseShader(c4d.Xbitmap) #...create a new empty bitmap shader...
opac_shader[c4d.BITMAPSHADER_FILENAME] = opac_file #...and load the filename in there
c4d_mat[c4d.MATERIAL_ALPHA_SHADER] = opac_shader #Assign the bitmap shader to the material's alpha channel...
c4d_mat.InsertShader(opac_shader) #...and insert it into the material
c4d_mat[c4d.MATERIAL_USE_ALPHA] = True #Activate the alpha channel
normal_file = GetTexture(doc, oct_mat, c4d.OCT_MATERIAL_NORMAL_LINK) #Get the texure filename from the normal channel...
if normal_file: #If we found one...
normal_shader = c4d.BaseShader(c4d.Xbitmap) #...create a new empty bitmap shader
normal_shader[c4d.BITMAPSHADER_FILENAME] = normal_file #...and load the filename in there
c4d_mat[c4d.MATERIAL_NORMAL_SHADER] = normal_shader #Assign the bitmap shader to the material's mormal channel...
c4d_mat.InsertShader(normal_shader) #...and insert it into the material
c4d_mat[c4d.MATERIAL_USE_NORMAL] = True #Activate the normal channel
bump_file = GetTexture(doc, oct_mat, c4d.OCT_MATERIAL_BUMP_LINK) #Get the texure filename from the normal channel...
if bump_file: #If we found one...
bump_shader = c4d.BaseShader(c4d.Xbitmap) #...create a new empty bitmap shader
bump_shader[c4d.BITMAPSHADER_FILENAME] = bump_file #...and load the filename in there
c4d_mat[c4d.MATERIAL_BUMP_SHADER] = bump_shader #Assign the bitmap shader to the material's mormal channel...
c4d_mat.InsertShader(bump_shader) #...and insert it into the material
c4d_mat[c4d.MATERIAL_USE_BUMP] = True #Activate the normal channel
rough_file = GetTexture(doc, oct_mat, c4d.OCT_MATERIAL_ROUGHNESS_LINK) #Get the texure filename from the roughness channel...
if rough_file: #If we found one...
rough_shader = c4d.BaseShader(c4d.Xbitmap) #...create a new empty bitmap shader
rough_shader[c4d.BITMAPSHADER_FILENAME] = rough_file #...and load the filename in there
c4d_mat[c4d.MATERIAL_USE_REFLECTION] = True #Activate the Reflectance channel
c4d_mat[mainLayerId + c4d.REFLECTION_LAYER_MAIN_DISTRIBUTION] = 2 #Change the Default Specular to a Beckmann type
c4d_mat[mainLayerId + c4d.REFLECTION_LAYER_MAIN_SHADER_ROUGHNESS] = rough_shader
c4d_mat.InsertShader(rough_shader) #...and insert it into the material
ReAssign(doc, oct_mat, c4d_mat) #Assign the new Cinema material inplace of the Octane one
c4d_mats.append(c4d_mat) #Add the new mat to our list of Cinema 4D materials
doc.InsertMaterial(c4d_mat) #Insert the Cinema 4D Material in the document
doc.AddUndo(c4d.UNDOTYPE_NEW, c4d_mat) #Add an undo step for the new material
return
def main():
my_doc = documents.GetActiveDocument() #Get the active document
my_mats = my_doc.GetActiveMaterials() #Get the selected materials
my_oct_mats = CheckSelection(my_doc, my_mats) #Checks the selected mats & returns only the octane ones
if my_oct_mats: #If we did find Octane materials...
doc.StartUndo() #Start the undo chain
RebuildMats(my_doc, my_oct_mats) #...re-create them as Cinema 4D mats
doc.EndUndo() #End the undo chain
c4d.EventAdd() #Add an event
if __name__=='__main__':
main()