the doc said:The usefulness of this node is very esoteric.
yes i don't really understand what's different with invoke,and don't know how to use it.
anyone can make a simple example file please?

Even though I definitly don't belong to the esoteric group that understands this node, I've put together a very simple example of how to maybe use it in its most basic form.

Generally you just convert a node, subnetwork or compiled node graph to geometry with the attribfromparm SOP (or create your own geo and attributes, change them or w/e) and then execute the network with the invokegraph.
The node documentation already explains it better than I can.

Maybe you already know all this but I have attached a file with everything I could figure out about this node so far.
I would definitly welcome a better answer about this as well if someone has a bit more in depth knowledge.

wow I didn't even know this node existed...
also the notion of geometry graph is totally new to me.

thanks for the example file Gorrod

Paul also did a nice video about invoke block which is closely related (and has a similarly vague help page)

https://www.youtube.com/watch?v=2eZZ_nSuSwk [www.youtube.com]

Another more or less practical example is creating new 19.5 husk procedurals. I've created a simple one here: https://www.sidefx.com/forum/topic/85494/?page=1#post-369964 [www.sidefx.com]

Also I remember somebody asks about calling parametrised geometry operation but with the limitation "hython only": https://www.sidefx.com/forum/topic/84322/?page=1#post-364485 [www.sidefx.com]

You'll definitely use it if you need it

I think right now it's mostly about hython or any other context where you need efficient access to sop. Solaris is the perfect example.

However I think using compilable operations is only going to evolve in the future. For example solaris layout brushes could be refactored to use compiled graphs. Generally using sop inside usd and probably storing those graphs in usd natively. etc

I can only speculate, but another thing is people keep asking for Houdini Engine that can be used in runtime. That will never happen However imagine that the part of the engine responsible of compilable networks is lean enough and can be extracted in separate runtime. This can unlock access to runtime geometry processing to any application (either from authoring and executing perspective).

Anyways currently Invoke Graph is a very low level node. When time comes to actually separate compilable networks to the new thing it'll definitely get much nicer ux.

Back in the day I made a crude version of this:



Now with the dictionary attributes and parameter serializing, etc you can do a lot sophisticated operations. One major use case for me in production is to have some kind of repetitive process like a post process to be invoked in multiple places without having to copy paste the same thing, and without creating an HDA just for this.

nice!! thank you all