Like maya, the original hda (the reference) is untouched. Any changes you make are stored in the hip, the equivalent of making reference edits in maya. The padlock goes red, dive inside and it no longer dimmed, you can edit away. If you want to make changes you can go back to the top of the hda, r.click and choose Allow editing of contents. If you dive inside the hda when the padlock is gray you'll see the nodes inside are dimmed you're literally locked out of making edits. In maya reference terms red means you might've made reference edits, gray means you've made no changes. Red means its unlocked and you might've made a local change, gray means its locked and matches the definition on disk. reverting any changes (the maya equivalent of deleting all reference edits).push those changes out of your hip and into the hda on disk (the equivalent of opening a second maya, opening the reference, editing and saving it).make modifications to the hda in the hip (the equivalent of maya reference edits).Now you have an HDA, you can do a few things with it: Lock states, editing and saving and reverting hdas Kiran points out an even easier method than drag and dropping parameters is to hold down alt + middle click the parameter and it will automatically add to the type properties. They'll be automatically channel referenced onto the top of the hda, super handy. The simple trick here is to put the dialog to one side, dive into your hda subnet, select nodes, and drag and drop parameters you want to control directly into the 'existing parameters' region. This is for you to customise the interface. Houdini shows you the Edit operator type dialog.Also be clear about the save location, if its just for you, fine, put it in your home folder, but you probably want to put it somewhere more public if its to share with others. The default is to prefix with your username, I usually remove that. R.click on the subnet, Create Digital Asset.If you see it, that's an HDA, and you can dive inside to see how the sausage gets made.Īgain several ways, but here's how its most often done: The clue is to look for the padlock icon next to the node. It's also worth noting how many native Houdini nodes are HDAs. Once you realise that all an HDA is a bunch of nodes saved together on disk, it all becomes a lot easier to understand. HDAs when defined will appear in your tab menu rather than expecting you to go File -> Load reference, which is neat.There's workarounds and tricks, but thats the ideal scenario. HDAs are supposed to be saved in a shared central location if you're in a big studio, meaning pipeline environment variables and all that.When you edit HDAs, you do it per node, one at a time. There's no 'maya reference editor' style thing to get a central overview of all HDAs used in the hip.As well as dumping a bunch of nodes to an external location, you can also put parameters on the top of the hda to control nodes within it, which is a trick you can't do with maya references.

Saving and updating is kind of magical and in-place, needs a mild leap of faith to trust its working.You can't just go File -> Export on a bunch of nodes, you need to use the HDA workflows to export.

They have a few features that make them a little more complicated than maya references: You export a chunk of a hip to an external file (eg c:/projects/library/coolthing.hda), now those nodes live somewhere else on disk, and you can bring them into your hip like a reference.

4 Load $HIP/hda on hip load via hou.sessionĪ Houdini Digital Asset is like a maya reference.

3 Lock states, editing and saving and reverting hdas.

Cant type in houdini engine maya