Hi everyone,

I'm currently developing a custom ROP node within the /out context, and my goal is to retrieve data from upstream nodes in the graph. The purpose is to "split up" the output process and publish individual portions to a database. For this, I need access to the upstream nodes in the node graph.

Initially, I considered using the SOHO system, but it seems SOHO is more oriented towards rendering workflows. From my understanding, it provides access to the render scene and the node that triggers the SOHO script, but not the broader Houdini Scene Graph, which makes sense given its rendering focus.

I also noticed that the Deadline node leverages a callback script, but this method didn’t work as expected when I tried to integrate it into a chain of nodes. For instance, when I added a null node at the end of the chain, the callback didn’t behave as I anticipated.

Here are my main questions:

- Is there a way to execute a callback script upon issuing a Render command in Houdini, with access to upstream node information?
- Alternatively, would it be feasible to adapt SOHO for this type of operation, even though I’m not dealing with a rendering context?

Since I don’t plan on generating any output, it seems like a pre-render script wouldn’t be the ideal solution. Any advice, suggestions, or insights on how to approach this would be greatly appreciated!

Thanks in advance for your time and assistance!