Switching regularly between Houdini and XSI, I often miss the Softimage passes system. Houdini gives us several options to render the same animation with different “render settings” in one hip file, but nothing so fast and easy to manage than the XSI passes system.
As this little diagram illustrate ( made with dial, a simple but very usefull free tool) , it looks like it is possible to build an HDA to mimic Softimage system in Houdini (if we considere that an object node with an “object merge” sop looks like a partition).
The HDA interface is there to allow the user to quickly set those “object merge/partition” with a material and some rendering option (only Phantom for the moment to mimic the primary ray toggle we could add using an override on an XSI partition).
The trick is to limit the scope of the mantra rop used by this HDA to only the “objects merge/partitions” from this HDA. The way I found is to use a null named “out_passe” below the object merge and a null named “not_passe” not connected and used for render and display.
Then I use a pre-render script like this one :
“opset -r on /obj/`opname(”../..”)`/partition_0/out_passe”.
and a post-render script like this :
“opset -r on /obj/`opname(”../..”)`/partition_0/not_passe”.
There is maybe a simple way to limite the scope of a rop to only one object node but I was too leasy to investigate more :-p.
Here is a little demo of an early version of this HDA.
For now each “passes” has its own renderer like in XSI before V6. A global/local system for the render options could be possible but it is so easy to link parameters and build its own rendering panel in Houdini that I don’t want to add such a feature.
To finished here is a picture of a famous french point break. No relation with the passe sytem, but I just don’t want that you call the police !
2 responses so far ↓
Delaney // July 24, 2008 at 6:17 am
why not just use Houdini’s built-in Takes system? as a former XSI user I can tell you it works great.
frenchdog // July 24, 2008 at 6:29 am
Takes are not so easy to setup than an xsi pass.
For example, if you need to create a new pass ( a funky pink material on several objects) you must create a take, and for each objects, assign the funky pink material.
Most often in Houdini I create a new object and merge inside all the objects I want to be pink. But then, I must exclude this “merged object” from other render rops. I find this workflow slow and that is why I create this digital asset.
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