Sweep with guide curve

Uploaded by rdomunkynet on 14.02.2011

>> In this tutorial, I'm gonna go over the sweep feature using a guide curve.
And in doing so, also introduce the idea of defining a reference plane using the normal
to curve definition, which is very useful when you're doing sweeps.
So sweeps are where we are taking a profile and basically sweeping it along some kind
of a path to create, create geometry.
So almost always with a sweep, you're gonna draw your path first, so let's just get
onto our front plane here, and I'll just draw a spline for our sweep path,
and I'll do something, I'll do a simple curve.
Something like this, okay.
Now let's say, I want to, I want to sweep a circle along this path
to create something like a, a bent rod.
The question is, where do I draw the circle?
Because I don't have any planes, I can't really draw it on the,
on the right plane here because it's in the middle of the path.
I really want to be able to draw it at one side or the other of the path.
But I don't have any planes out there that make sense.
And, really, you want to draw your profile, so that you, in most cases you want
to draw your profile so that it's normal to the path, meaning it's,
it's kind of perpendicular to the path in a 3D sense, so that it's,
it's going to be extruded straight out along that path.
So what we need to do here is actually define a reference plane using a particular
definition type, which is called normal to curve.
So I'm gonna insert reference geometry, insert reference geometry,
oh, I'm still in my sketch here.
Exit my, exit my path sketch, and let's call this path.
So insert reference geometry plane.
And I'm going to select my path, and one of the two endpoints here.
Doesn't really, in this case it doesn't matter which one.
And you can see when I do that, it automatically knows that I,
I want to do this normal to curve definition type, okay?
So basically what that means is that the plane that is defined here is defined
in such a way that the path, the curve that I selected is normal
to it at the point that I selected.
Meaning that the curve is coming straight out of the plane.
This is exactly what I want for defining a sweep profile, okay?
So do this, okay.
Let's call this my sweep profile plane.
And now if I start a sketch on this plane, it's real easy to draw my profile.
The origin, those right words is right where the original curve is touching,
my path curve is touching, and it looks
like I don't have automatic relations turned on, let me turn that on, okay.
So let's say I've got, that's my profile, that's the, the diameter of my,
of my bar stock or whatever I'm, I'm doing here.
So I'll exit this sketch, and now I can do a sweep.
So swept [inaudible] face, it asks me what's my profile.
I'm gonna say sketch two here.
What's my path?
It's this path curve here, okay.
And so the profile is swept along the path, easy enough.
Now one more thing I can do is, I can add a guide curve that changes the size
of the profile as it's swept along the path, so let's do that.
So I'm actually gonna, I'm gonna undo that swept [inaudible] space,
let me rename this to profile, okay.
So, and let's get this plane out of the way too, let's hide this.
All right, so I'm gonna do a guide curve now.
Again, I'm gonna do this just for convenience on the, on the front plane.
It's, it happens to be the same plane as my, as my path here,
but it doesn't necessarily have to be.
So I'll start another sketch here, and let's say I, I want to start something like that,
and then maybe it's gonna get a little thicker out here and thinner in here,
and end up flaring out like that, okay?
So I would expect my profile as it goes along here to get bigger out here,
smaller in here, and then bigger again, okay.
So let's see if this would work.
Let's call that my guide curve.
Okay. So again, I'm gonna do swept [inaudible] space, what's my profile,
this one, what's my path, this one, and then guide curves, choose a guide curve.
And I click on that, and it says no.
Well it doesn't say no, but it doesn't show me a preview.
And, when I click on okay, it says it's invalid,
it does not intersect the section plane.
Which means it doesn't, it doesn't intersect my profile basically.
All right, so let's go back and fix that.
I have to make sure when I'm doing my guide curve that it intersects the profile here.
So I'm gonna add a relation to help me with that.
I'm gonna choose the end of the guide curve, and I'm gonna choose my profile,
and I'm going to add a pierce relationship.
Pierce means kind of what it sounds like.
Basically if I rotate this around you can see that this profile
on one plane is being pierced by this curve coming in from another plane,
and they're coincident at this point.
That's basically what the, what the pierce means.
Okay, so now that we've got that relationship in place we can go back and try again
with our swept [inaudible] space.
So again, profile is this one, path is this one, guide curve, and I'll select that.
All right.
So now I've got a shape where the profile is going along the main path here,
but it's also being influenced by the guide curve,
in that the guide curve is making the profile larger and smaller
as it goes along the path, okay?
So you can get a lot of interesting geometry just from that simple tool in the,
in the swept [inaudible] space.