Python Rop: part 1 — Intro

This post will be a short tutorial with multiple purposes. Its a solid intro to HDA building for beginners that will yield something actually useful. For more advanced users it might contain some useful tricks, and serves as a quick tutorial on how to build the node which will likely take under an hour.


Convenience. We often talk about creating conveniences. It usually implies something that does not add any new feature or functionality; it simply enables a user in a more familiar or intuitive way. A python Rop simply provides the familiar python interface available in other context to Rops.

While the pre and post scripts exist on many the included Rops, many third-party Rops, especially those for render engines, may not. This allows having that additional functionality without altering the shipped Rops or having to maintain wrapper otls ā€“ just to encapsulate multiple nodes elevating their interfaces to a single one ā€“ per node.

A third use is for altering the network during evaluation at render generation time. There could be any specific needs that would require render time evaluation of the graph or require adhoc alterations. Having a python sop couldbe valuable for prototyping, debugging, and adhoc one-offs where no real development resources are necessary.

This is a cool little node and when we are done walking though the tutorial will have a useful tool in our Houdini arsenal. I am working in non-com and have made the Rop available for download for those that want it to dissect along with the tutorial or to skip the tutorial all together. I will try to make a normal HDA available in the near future. I would appreciate it if you like the HDA and want to share it, you send them to the blog so I can see interest in various projects I make available to plan future posts.

With that said, lets get to building.