Ok,
Here's a simple, yet pointless example:
1.) Open a script editor, paste this code in, and execute it... so the
function is defined
def rebuildNode(node):
if(len(nuke.allNodes(group=node)) < 3):
nuke.createNode('Blur', inpanel=False)
return(1)
2.) Paste this Group into Nuke. It starts as an empty group. The
expression defined on the inputChange knob will call the function we
defined above. Anytime there are less than 3 nodes inside the Group, a
Blur node will be created. (To see it in action, Interact with the Group,
change the input, Expand the Group, delete the Blur, and then see it
recreated, etc )
set cut_paste_input [stack 0]
version 6.3 v1
push $cut_paste_input
Group {
name Group1
selected true
xpos 872
ypos -149
addUserKnob {20 User}
addUserKnob {7 inputChange}
inputChange {{"\[python -execlocal ret\\ =\\
rebuildNode(nuke.thisNode())]"}}
}
Input {
inputs 0
name Input1
xpos 878
ypos -161
}
Output {
name Output1
xpos 878
ypos -21
}
end_group
3.) Redefine the rebuildNode function to be this. (NOTE: change the path in
the nodePaste command to a .nk file that exists on your computer. I simply
ran "Export Nodes as Script" on a Grade node to generate C:/test.nk):
def rebuildNode(node):
if(len(nuke.allNodes(group=node)) < 3):
nuke.nodePaste(r'C:/test.nk')
return(1)
4.) Delete the Group from step 2 and then repaste it into Nuke again.
As far as I can tell, nuke.nodePaste() doesn't work in this context. I get
error messages like this:
RuntimeError: The Grade command is not allowed in a string or expression.
Is the nodePaste being interpreted as a code string for the expression to
execute?
-Paul
On Thu, Dec 1, 2011 at 10:45 AM, Paul Hudson <[email protected]> wrote:
> Hi,
>
> I am building a Group node that rebuilds it's internals based on what its
> input is.
>
> I have written a function that works fine when launched via the script
> editor, like so:
> rebuildNode(nuke.selectedNodes()[0])
>
> I am trying to trigger it when the input changes, so I tried putting my
> function in a Python Expression on a knob (in "series of statements" mode):
> rtn = rebuildNode(nuke.thisNode())
>
> This does not work and it appears to be a call to nuke.nodePaste() that is
> causing the problem. When I put a nuke.nodePaste() call directly in the
> expression I get this error:
> "RuntimeError: The Group command is not allowed in a string or expression."
>
> So the question is, Does nuke.nodePaste() not work inside a Python
> Expression or is it a context issue? In my original function I used
> myGroup.begin() before the nodePaste. I have tried it with and without the
> myGroup.begin() call in the Expression... doesn't work either way.
>
>
> Thanks for your help,
> Paul
>
>
>
>
>
>
>
>
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