Ok, I have a stupid quiestion, so what? Can anybody explain me this, please?

I had quite a heavy scene, about 1GB textures on a few hundred of objects.
I applied (by script) one instance of HDA shader for every geometry. 1 HDA but 200 objects = 200 shaders.

At some point I realized that I made a mistake and I have to rewrite my shader. I open a new scene and made from scratch a new shader, I called it the same as old one and saved to another library in my OTL path.
Shader is completely different, only parameter's names match.

When I opened my scene, Houdini automagically loaded new otl, found shader of the same name (but made from scratch - this was not a version of old one) and applied new definition to my scene.

I thought that the work flow is that I, by my self, install OTL then choose new definition among available, then Houdini tries to match definitions. But Houdini turned to be smarter here than I thought.

I was happy with this but it completely surprised me at the same time. The new shader could be completely different entity. How Houdini knows that this was a new version - just by name?

thanks,
sy.

Take a look at the options in the Windows > Operator Type Manager. I think it looks at timestamps.

yeah, go through the Windows > Operator Type Manager and see what's up
also go through the help on these topics…
HDA paths, updates etc are a very big, complicated issue (to be honest) - but it's worth it.
issues like this take days of meetings here to resolve - there is a great deal of flexibility in HDAs, but you have to understand the implications of your choices.

I'd also recommend reading/view Jeff's Old School Blog(under the Learning section). There is some great hda information there.

I definitely should look at it again (plus read Help(again) ) but in the same time I use HDA since their introduction. The only thing bothered me was a way Houdini deals with replacing scene content presents in many otls. What if my hda “constant” would be CHOP operator not shader? This was my concern.

Houdini 9 loads now any otls present in otl path. This didn't happen in 8 as I remember. I don't fill this is wrong, I was just surprised.


sy.