How to set 'inputs' for the Merge (AiMerge) node with an array of operators in python api

[markus.ng]

I'm trying to set the 'operators' attribute on a procedural node that i'm setting in Arnold Python api.

The following code will return the error:  
============================
# Error: : parameter inputs is an array of type NODE, not STRING # 
============================

My attempt was to create an array of strings and then set the 'inputs' Merge node to the array of strings (list of the names of the operator nodes) 

I can't find any clear docs or examples on how to create an Array of nodes or how to set the 'inputs' for the Merge node.

Thanks!

#================== code starts =======================

from arnold import *

AiBegin()
AiLoadPlugins(os.getenv('ARNOLD_PLUGIN_PATH'))

#ctx = arnoldUtils.AiContext()`
geo_filename = "c:/test/chr_test.ass"
asset_name = "chr_test"
node_name = asset_name

cur_node = AiNode('procedural')
AiNodeSetStr(cur_node, 'name', node_name)
AiNodeSetStr(cur_node, 'filename', geo_filename)
string_replace_win_name = '%s_string_replace_windows'%(node_name)
n_replace_win = AiNode("string_replace")

AiNodeSetStr(n_replace_win, 'name', string_replace_win_name )
AiNodeSetStr(n_replace_win, 'selection', "*")
AiNodeSetStr(n_replace_win, 'match', "/n/")
AiNodeSetStr(n_replace_win, 'replace', "n:/")
AiNodeSetStr(n_replace_win, 'os', "windows")

print "=============== create string_replace lin"
string_replace_linux_name = '%s_string_replace_linux'%(asset_name)
n_replace_linux = AiNode("string_replace")
AiNodeSetStr(n_replace_linux, 'name', string_replace_linux_name )
AiNodeSetStr(n_replace_linux, 'selection', "*")
AiNodeSetStr(n_replace_linux, 'match', "n:/")
AiNodeSetStr(n_replace_linux, 'replace', "/n/")
AiNodeSetStr(n_replace_linux, 'os', "linux")

print "-------------- setup array string"
l_op_str = [string_replace_linux_name,
            string_replace_win_name  ]
num_ops = len(l_op_str)
print "======================AiArrayAllocat:"
# create String object with predetermined size
#operator_AiArray= AiArrayAllocate(num_ops, 1, AI_TYPE_STRING)
operator_AiArray= AiArrayAllocate(num_ops, 1, AI_TYPE_STRING)
cur_index = 0
# populate list
print "before loop"
for cur_op in l_op_str:
    print "adding to aiArray:%s"%cur_op
    AiArraySetStr(operator_AiArray,cur_index,cur_op)
    cur_index +=1
print "=================create AiMerge"

asset_aiMerge_name = "%s_aiMerge"%asset_name
node_aiMerge = AiNode('merge')
AiNodeSetStr(node_aiMerge, 'name', asset_aiMerge_name)
#
AiNodeSetArray(node_aiMerge,"inputs",operator_AiArray)

#============== end code =====================


'''
#Example .ass merge with operators, output as exported MtoA

procedural
{
 name /aiStandIn/aiStandInShape
 visibility 255
 matrix
 1 0 0 0
 0 1 0 0
 0 0 1 0
 0 0 0 1
 override_nodes off
 operator "/aiStandIn/aiStandInShape/input_merge_op"
 filename "N:/render-caches/arnold/grimm/gm01/seq_00999/shot_0555/depts/lgt/geometry/chr_king_c/chr_king_c.0004.ass"
 auto_instancing on
 declare dcc_name constant STRING
 dcc_name "aiStandInShape"
}

string_replace
{
 name fixpath_aiStringReplace1
 selection "*"
 match "/n/"
 replace "n:/"
}

string_replace
{
 name fixpath_aiStringReplace2
 selection "*"
 match "/N/"
 replace "N:/"
}


merge
{
 name chr_test_aimerge
 inputs 2 1 NODE
"fixpath_aiStringReplace1" "fixpath_aiStringReplace2" 
}

[Stephen.Blair]

Here's how I do it for polymesh.shaders, you should be able to do something similar for merge.inputs:

n = AiNode( "polymesh" )

s1 = AiNode( "standard" )
AiNodeSetStr( s1, "name", "aiStandard1" )


s2 = AiNode( "standard" )
AiNodeSetStr( s2, "name", "aiStandard2" )

s3 = AiNode( "standard" )
AiNodeSetStr( s3, "name", "aiStandard3" )


shaders = AiArrayAllocate(3, 1, AI_TYPE_POINTER)
AiArraySetPtr(shaders, 0, s1)
AiArraySetPtr(shaders, 1, s2)
AiArraySetPtr(shaders, 2, s3)

AiNodeSetArray(n, 'shader', shaders)

[Stephen.Blair]

The C++ code for MtoA uses a AI_TYPE_NODE array, so maybe that's the way.
I haven't tried it yet...

[markus.ng]

Excellent, thx. It's using a combination of

AI_TYPE_POINTER and AiArraySetPtr with the node object to be added.

Thanks for your help!

Here's the working code:

======================

asset_name = "chr_test"
node_name = asset_name

cur_node = AiNode('procedural')
AiNodeSetStr(cur_node, 'name', node_name)
AiNodeSetStr(cur_node, 'filename', geo_filename)
string_replace_win_name = '%s_string_replace_windows'%(node_name)

n_replace_win = AiNode("string_replace")
AiNodeSetStr(n_replace_win, 'name', string_replace_win_name )
AiNodeSetStr(n_replace_win, 'selection', "*")
AiNodeSetStr(n_replace_win, 'match', "/n/")
AiNodeSetStr(n_replace_win, 'replace', "n:/")
AiNodeSetStr(n_replace_win, 'os', "windows")

string_replace_linux_name = '%s_string_replace_linux'%(asset_name)
n_replace_linux = AiNode("string_replace")
AiNodeSetStr(n_replace_linux, 'name', string_replace_linux_name )
AiNodeSetStr(n_replace_linux, 'selection', "*")
AiNodeSetStr(n_replace_linux, 'match', "n:/")
AiNodeSetStr(n_replace_linux, 'replace', "/n/")
AiNodeSetStr(n_replace_linux, 'os', "linux")

l_op_nodes = [n_replace_win,n_replace_linux]
num_ops = len(l_op_str)
operator_AiArray= AiArrayAllocate(num_ops, 1, AI_TYPE_POINTER)
cur_index = 0

for cur_op in l_op_nodes:
	AiArraySetPtr(operator_AiArray,cur_index,cur_op)
	cur_index +=1

my_aiMerge = AiNode('merge')
AiNodeSetStr(my_aiMerge, 'name', "my_aiMerge")
AiNodeSetArray(node_aiMerge,"inputs",operator_AiArray)

AiNodeSetPtr(cur_node, 'operator',my_aiMerge )

======================