A new video tutorial (and scene file) has been added to the Learning section of the site. This tutorial covers a new feature in Houdini 9.5: The Wedge ROP. Wedging renders a specified ROP multiple times, each time varying some parameters in the .hip file. This is useful for exploring how changing parameters will affect the final product in things such as simulations.

http://www.sidefx.com/index.php?option=com_content&task=view&id=1396&Itemid=132 [sidefx.com]

great tutorial. Im surprised others have yet to comment.

That watermark post-script is awesome.

You show the method of using the Wedge ROP with parameters, how does it differ when using it with takes.

Will using the $WEDGE with the watermark script automatically show the parameters that have changed between each take? Im not sure on that part.

But great tutorial. Keep it up.

$WEDGE is a variable that will contain the Prefix parameter on the wedge rop, followed by an underscore, followed by either the Name paramter or if Name has been unassigned the channel, followed by another underscore, and finally the value from the wedge.

so if your:
prefix is wedge
name is empty
channel is ../../obj/sphere_object1/point1/diffr
and the current wedge value is .5

$WEDGE will be wedge_diffr_0.500000

If you are wedging multiple parameters at once, say

../../obj/sphere_object1/point1/diffr and ../../obj/sphere_object1/point1/diffg

Then your wedge values will end up being something like:

wedge_diffr_0.000000_diffg_0.000000
wedge_diffr_0.500000_diffg_0.000000
wedge_diffr_1.000000_diffg_0.000000
wedge_diffr_0.000000_diffg_0.500000
wedge_diffr_0.500000_diffg_0.500000
wedge_diffr_1.000000_diffg_0.500000
wedge_diffr_0.000000_diffg_1.000000
wedge_diffr_0.500000_diffg_1.000000
wedge_diffr_1.000000_diffg_1.000000


Wedge wouldn't create a variable out of everything that has changed between takes, but only the values that would be declared in the wedge rop.


As far as running a Wedge on a mantra node rendering specific takes, the Wedge ROP does appear to be able to bypass values in a take whether or not that parameter has been included in the take or not. So, that is something to be aware of.

Allegro
Wedge wouldn't create a variable out of everything that has changed between takes, but only the values that would be declared in the wedge rop.

ahh thats what i thought. I guess you can rename your takes with descriptive names name then right?

So i dont really understand the “By Take” Wedging procedure.
On the help it says.

Wedge Method

Controls how the scene is varied.

By Channels
Each of the Wedge Parameters is …….

By Take
One wedge is performed for each immediate child of the given parent take. The output driver’s take parameter is set to each child take’s value.

Im not fully clear on that.

Oooooh, sorry, I misunderstood your question. I thought you were talking about rendering a mantra node that had a specific take assigned to it.

In the case of you changing the Wedge Method to “By Take”

$WEDGE will equal Prefix_TakeName
So if you have created at take called take1, and it is a child of Main, if you were to render your Parent Take as Main, you will render take1

so $HIP/$WEDGE.pic might equal $HIP/_wedge_take1.pic

You could use this as a workflow to render all your takes in sequence rather than using a string of mantra nodes to render all of your takes.

When wedging takes, the node does not give you the option of wedging channels as well.

See the attached file.

ahh tottally get it now.

So if i wanted to wedge by take, it would basically spit out both takes iun sequence, and if i was clever with my naming certin key parameters would be visible if i used the post render script and then if i want to test a few parameters on a single take then i would use another wedge rop and use the wedge by channel method.

thank for you help on this stephen.

would there be any interest in having a button or whatnot that could create takes based on the wedge?
so in the video example you could generate 3 takes based on the anglular velocity?
might be worth thinking about?

i think there would. If it was an option that could be enabled and disabled. and maybe an adjustment in the take list, if you could view takes generated by the wedge so no one gets confused.