Extracting different EXR channels from single image import node...?

[rawalanche]

Is it possible? So i do not have to duplicate numerous import, and then have to rewire them all once the input changes? I tried several different nodes with names indicating they could be doing what i want them to do, but i did not find a node that would extract different EXR channel (for example reflection pass) from an image import node.

[Steve_Curley]

File > Import > [navigate to the .exr and highlight it] > Right-click the filename > Import All Channels. I think - worth a try 😉

[rawalanche]

Thanks for quick reply, but this unfortunately does not work. It just creates compound with all the duplicate nodes inside. So if i for example have 20 channels, and i get an updated output, i still have to go through each single node and change the file path. 

[Steve_Curley · Accepted solution]

But they are at least all in one place inside the "tool". Might be possible to have a Python script ask for the new filename and replace the the existing ones (one per Image Import node) with the new one, or effectively click the Reload button for each node (if the filename is the same). Sadly I know next to nothing about Python, but there are some examples provided which might provide some pointers.

Looking at the Channel assignments they do seem to be tied to an Image Import node, which is presumably why the Import All Channels creates multiple input nodes rather than a single node with multiple outputs.

[rawalanche]

Yeah, seems like scripting is only possible way in this case. Thanks for your effort 😉

[Steve_Curley]

With any luck one of the local gurus will notice this and at least confirm/deny the possibility (of a script). Looking at:-
[CompositeInstallDir]\Resources\Scripts\Actions\multiChannelImport.py
which is (apparently) what the Import All Channels actually does, would suggest that it is (possible).

[FalconCrest]

Scripting is possible the only way, I feel your pain.

[rawalanche]

It is just a minor thing though. I am really glad composite is now back in the game as i know how to avoid crashes (having more than one frame in my composition) 🙂

[Steve_Curley]

I'm just glad they now include a decent compositor with Max - even if it does crash occasionally 😄