Houdini: Implement Load Asset LOP HDA

[BigRoy]

Changelog Description

Implements a LOPs (Solaris / USD) asset loader to reference or payload in files into the Solaris stage.

• Has separate parms for project_name, folder_path, product_name, version and representation that describe which product to load. Changing any of those parms will trigger an update to load that particular version, as such - you can dynamically drive these using any way Houdini allows you to, e.g. the project name and folder default to respectively $AYON_PROJECT_NAME and $AYON_FOLDER_PATH representing the project and folder of your current context.
• Has parms and functionality to automatically attach a 'version' thumbnail if the version entity being loaded has one. Disabled by default but can be enabled, resized, etc. per node.

Additional info

This is a further enhancement from this OpenPype PR ynput/OpenPype#5831
Some of that can also be seen in the presentation I gave at the Ynput Summit 2024 here.

We have actually used an OpenPype-equivalent in production. Nonetheless I still expect many bugs (and feature requests) so input is greatly welcomed. I'm inviting you to break it and provide feedback. Also provide screen recordings if you get stuck so we can see how "other users" try to use it. @fabiaserra @MustafaJafar @moonyuet @antirotor you are cordially invited.

I did a pretty quick refactor to AYON, so testing is greatly appreciated! :)

---

Other visual reference of a 'similar' implementation by @fabiaserra here.

Testing notes:

1. Load and manage USD assets via the Load Asset LOP (and should also work via the manager)

[BigRoy]

@iLLiCiTiT this also uses some logic to store a temporary thumbnail alongside the scene so that Houdini can display it - in the screenshot with the PR for example the checkerboard image above the node bottom right. There may be much better ways, but for now I just wanted to highlight this uses some version thumbnails logic from ayon_api.

[MustafaJafar]

I had to make these changes on my side to make it work.

[MustafaJafar]

I have two suggestions to make this HDA more fun.

1. A button to select folder path (which is the same as the button in the publisher UI)
   This logic works on my side.

"""Select a folder path."""
from ayon_core.pipeline import get_current_project_name
from ayon_core.tools.publisher.widgets.folders_dialog import FoldersDialog
from ayon_core.tools.utils.host_tools import get_tool_by_name
from ayon_core.hosts.houdini.api.lib import get_main_window


project_name = get_current_project_name()

main_window = get_main_window()
publisher_window = get_tool_by_name( tool_name="publisher", parent=main_window)

dialog = FoldersDialog(publisher_window.controller, main_window)
dialog.exec_()

selected_folder_path = dialog.get_selected_folder_path()

print ("asset name:", selected_folder_path)

2. A button to select a USD product name.
   This snippet works. it gets a list of usd products within a particular folderpath

import ayon_api

project_name = "Robo"
folder_path = "/Assets/Character/bigrobo"
my_product_type = "usd"


id_only = ["id"]
folder_entity = ayon_api.get_folder_by_path(project_name,
                                            folder_path,
                                            fields=id_only)
my_folder_id = folder_entity["id"]

my_usd_products = ayon_api.get_products(
    project_name,
    folder_ids = [my_folder_id],
    product_types = [my_product_type]
    
)

print(list(map(lambda p: p["name"], my_usd_products)))

irrelevant to this PR.

3. I think adding a product type selector in the HDA can be used to enhance the previous code snippet. which can be a starting point to have a generic loader. where the digital asset acts as a container and nodes inside it are created based on the data in each loader.
   I'm not sure if I rephrased it correctly. but, I hope you get me.

[BigRoy]

I have two suggestions to make this HDA more fun.

Yes, please. I'd love there to be buttons that show a mini-list dialog to pick from. Feel free to make a PR to my branch with those features. it'd be greatly appreciated 😍 - I looked into it in OpenPype but the dialogs then weren't to trivial to hijack into but if you have a good hack for AYON, go for it!

Would you be able to contribute?

It would be a major help for this loader HDA tooling anywhere in Houdini. :)

I had to make these changes on my side to make it work.

Interesting, seems like I might have missed pushing a few commits - because it did work for me.

[MustafaJafar]

Would you be able to contribute?

I was born ready to contribute 🤓..
Hopefully, tomorrow I'll tinker around it.

[MustafaJafar]

This is super cool and it works.

I didn't test some of its features : thumbnails (I don't have products with thumbnails) and load options (look fine as it's just straight forward copied parameters).

[Lypsolon]

Here are some things I found.

Sorry for the one commit I made; I will leave it as comments from now on.

Also, I have one question in case you tested it. In the on_save() function in pipline.py, there is a call to a function that apparently only exists in the Maya lib.py, and it errors on save. I'm not sure if it does that for you, too.

Lovely stuff btw.

[moonyuet]

Tested successfully in Houdini 19.5

[MustafaJafar]

It is so cool!

[BigRoy]

Sorry @moonyuet @MustafaJafar I accidentally re-requested the review on the wrong PR.

[MustafaJafar]

It's working as cool as before

[MustafaJafar]

@moonyuet @BigRoy any last words before merge ?

[moonyuet]

@moonyuet @BigRoy any last words before merge ?

no, it can be merged.