hi,
currently working first time with the Op_Id. Got it working but had a few questions.

I am working on a Project which has lots of Elements and when I read out the Op_Id in the viewport i get a different Result (ID) than in the render.

Also my objects range over 50000 ids and i dont really know why. is there some way to reset the Object ID's?

Its not a big issue as i get it working in the comp but its a bit frustrating finding the Id's atm. Maybe I do something wrong?

Before I was using my own shader with a custom MaterialID pass with color code i rendered out as a seperated pass. Might this be a better faster option?

any suggestion?
thanks in advance.

Op_id It's the unique id of the OBJ that generated the geometry (see OP_Node::getUniqueId() in the HDK). However, it increases monotonically for each operator created while Houdini is running; so the longer your session lasts and more ops you create, even with New Scene in between, the higher this number will be.

That was a quote from half dan. It really depends what your doing. I find op ID for comp to be only useful in very certain circumstances. Your better off creating a matte in a shader often or not. It just really depends what the end goal is.

Rob

thanks for your answer.
i'm just trying to get some quick alpha masks from them later to be used for grading.
I have now setup a custom ID Parameter in a Mantra Shader and use this one which just seems more flexible, artist friendly.

anyway is there a way to reset the ID after a long session to avoid high numbers?

Also is there a way to disable both the Op_Id and Prim_Id Passes if you dont need them?

Hi,
Theres nothing to turn off as you put it, you just don't turn on the image outputs in the mantra ROP . The best set up to make your own ID shader based / SOP attribute , is here in a post I made.

http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=28648 [sidefx.com]

Rob