How to use the Script SOP for modifying vertex attributes

General TouchDesigner Discussion
1

I’m trying to modify the vertex attribute in a ScriptSOP and can’t quite get my syntax worked out.

def onCook(scriptOp):
	mesh = scriptOp.inputs[0]
	scriptOp.copy(mesh)
	
	for i in scriptOp.points:
		i.Cd = 1 # this works to set the point attrib color Cd
		#i.uv = 0 # this does not work because my uv attribute is on the vertex
	
	return

to loop through vertex I’ve tried this

for i in scriptOp.vertex:

but ^ this also does not seem to work?

I’ve looked through the op snippets and it would be useful to see more modifying of attribute examples, like bringing in a piece of geo and modifying point, prim and vertex attributes. Eventually I’ll need to wrangle more data types in geo and the python commands to access those counterparts.

2

According to the docs, a Vertex instance is always contained within a Prim object.

So looping over all vertices can be done like this:

def onCook(scriptOp):
	scriptOp.clear()
	sop = scriptOp.inputs[0]
	scriptOp.copy(sop)
	
	for prim in sop.prims:
		print("primitive: ",  prim.index)
		for v in prim:
			# do something with v, which is a Vertex
			print("vertex index in prim: ", v.index, "uv attribute for this vertex : ", v.uv.val)

I did not yet succeed in changing the uv attribute values for a vertex like this, not sure if that is supported atm

3

Thanks Idzard,

Unfortunate that uv vertex doesn’t work. I guess ill do the old SOP >>> DAT trick, modify my values, then do the conversion back from DAT >>> SOP. I wish modifying SOP attributes was easier to script natively in SOPs, but maybe someday.