Hi guys.
Welcome back to Game Character Rigging with Houdini.
In this video, we're going to make our first digital asset.
It's not going to be too taxing, but I think it's quite an important tool to have and I tend to get
a lot of use out of it, especially in rigging.
So what is it?
Well, it's a rig pen, which is just a simple control object that we can drop into Houdini.
And what it does is basically a pen shaped thing like that with parameters for the length.
So we can adjust the length and parameters for the radius of the sphere as well.
And what we use this for is in certain situations, the the transformation handles and the objects that
an animator wants to manipulate can be sort of quite hidden within the volume of the geometry.
So it's often useful to provide a very clear indication of something that the animator can grab on to.
So the plan for our character model is we're going to have a rig pinned to control the jaw.
So if you imagine the jaws pivot point being back here, the rig pen will stick out through the bottom
of his chin and pop out there indicating to the animator that that's a control that you can grab onto.
Likewise for the head, the pivot point will be down here somewhere, but we'll have a control object
at the top of his head again, indicating to the animator that that's an object that you can grab onto
to control the relevant body parts.
You'll see these quite a lot in animation rigs and they're really useful.
I tend to put some as well the shoulder blades facing back as well.
So just to make it easier to sort of box select those control objects if you want to rotate both shoulders
at the same time, some rigs like to use them for the finger joints, so you might find them sort of
looking like this.
So you can very quickly just drag a box selection to grab all those three control objects and animate
them as you see, as you see fit.
So with that, like I said, it's not the most taxing piece of digital art that will do.
However, it is very useful.
So let's get started.
I'm going to drop down a geometry note.
I'm going to give it the name pin.
It's going to make a little bit of space for myself in the network view.
I'm going to drop down a sphere.
On the line
and a copy, two points.
So we want to copy the sphere to the line.
Okay.
I'm just going to drop the size of that sphere down.
So it's going to middle, click and drag to create a pen type looking thing.
And in the two points, you can see we are copying it to both points.
We don't want that.
So we can just specify a point number one to copy it to the top and then merge those two streams together.
So we get a complete object.
And there we go.
Those are pen.
And at the end, I'm just going to append a color node so we can set a color and give it my default
rig green, which indicates a control object.
Okay.
So there we go.
That was pretty taxing.
I'm sure you'll agree.
So I'm going to jump up a level and I'm going to right click on that and create a digital asset.
Okay.
So you pop up with the digital asset creation.
I'm going to save that to my HDR in my hit folder.
So if you remember back to the project that we created at the start hit point to that project.
And in my HDR folder, I'm just going to call Rick Pen Digital Asset.
Rick Pen.
That all seems good.
So I'm going to hit except.
Okay.
So we're just going to revert that layout.
And in the parameters, the basic parameters, here we go.
So we can specify that it requires and inputs a maximum input of one we're not really to foster by having
a minimum and but maximum input is going to be one.
We don't want to ever have more than one input to this.
It's going to be basically used just to grab transformations.
Okay.
So over in the parameters, we can sort of we can we don't need to see the render tab so we can make
that invisible and the misc type as well.
We don't really need to see that so we can make those things invisible.
The transforms obviously very important to as and we'll want to make sure that those positions and rotations
are available.
You could, as this is a fold kinematic control primarily you could hide the translate and just focus
on the rotate.
We shouldn't ever need to use pivot, pivot, translate or pivot rotate so you could possibly hide them.
But just for the sake of this, I'm going to I'm going to keep them all visible.
Okay.
So now we need to populate this with the parameters that we want to to add to our digital assets.
So to do that, I'm going to drag across a folder and drop it on the root.
And call it rig ten parameters.
Apply that, and I'm just going to dive into my rec pin asset.
And grab the sphere uniform scale and just drag that into my rec pin folder.
I'm going to grab the length.
And drag that into the rec pen.
Also going to drag this direction because this will come in handy.
And put that in there as well.
I'm also going to grab this color so we can specify a color for our pen.
And with that we should be pretty much done, apply and accept.
So if we jump up now, we've got a neat folder where we can manipulate how we need this pen to look,
and we've got access to the transformations as well on there so we can set key frames and things like
that.
One more tweak that I want to I want to do that's quite important is the rotation order of this control
object needs to be aligned with our bones, as we've mentioned before.
If you think back to the distant past, when we looked at the Rubik's Cube analogy whereby if you know,
we need to know the rotation of the Rubik's, we need to know which way up to hold the Rubik's Cube
involved in order to solve it.
Likewise, this big pen needs to match the bones rotation order and the bones rotation order by default
is opposite r y x.
So we'll make sure our rec pen has that very same rotation order so that Houdini can translate our input
into the correct rotation.
So that's quite an important step.
So with that, we're going to save that note type and match the current definition just to lock it back
up again.
So that's.
That's saved it to a desk now so we can simply drop down our rec pin.
And there is, in fact, is that one.
And I've got a couple in there from previous builds, so don't worry about that.
You should have it in your digital assets folder.
Okay.
So one sort of visual tweak that I like to make just to indicate control objects in my network view
is I like to set the shape to the circle and if you want it to come as default, you can hold down control,
grab the shape and drop it onto the notes.
That will save that shape as a as a default, if you like.
So I find that quite useful.
Likewise, on the color, I tend to set all my animal friendly control objects to this light green.
It makes them very easy to see.
And again, if you just hold down control, you can drag a color onto a note and that will save it as
a default.
So every time you drop down a rec pin, it comes in with with the look that you that you're expecting.
Okay.
So like I said, it's not the most exciting piece of digital art that we'll ever do, but it's, you
know, a useful tool.
And we can position these where we need them to be.
We can alter the direction of them so we can make sure the orientations are correct.
Yeah.
So useful.
What I'd like to do as well is make it super easy to grab.
So what I can do is I can just grab the digital asset and drop it onto my rigging shelf tool.
Okay, so now to place one of these down is just a matter of clicking and where's it gone?
There is just a matter of clicking on the on our shelf tool icon, which is really quick and useful,
admittedly not maybe as quick as just tapping tab and typing it out, but you know, it makes it makes
good sense to have it visible.
One tweak I'm going to make finally is just to tweak the icon.
So I'm going to jump over to options.
And I've managed to find an icon in the rigid body tab that is looks pin like, so we're going to borrow
that.
So it's the rigid body parent constraint.
We're going to copy and paste that in there.
So I'm going to apply and accept this cancel out of that.
So if you look now, we've got a nice little rec pin icon on our custom shelf tool, so make it really
quick just to drop down our new rick pins.
Okay.
Like I said, not the most exciting piece of digital art will do today.
But I think for the next couple of videos, we're going to jump into some python code and populate the
two useful tools that we've put on our.
On our shelf there.
So I hope you ready to do a bit of coding.
And I shall see you hopefully in the next video.
Thank you.