Join Veejay Gahir for an in-depth discussion in this video Moving control points, part of Alias Essential Training.
- In this video, we're going to take a look at how to move control points and hulls using the Transform CV tool. In the control panel, right down at the very bottom, we have an option there. If we double-click that, we can open up a dialog box that says "Transform CV Options." Essentially, this is another controlled way of moving CVs and hulls. We can select which entity we're trying to move, CVs or hulls. Let's just start off with CVs. We're going to be moving CVs, and we're going to be moving, rotating, scaling, non-proportional scale, pivot, or proportional modification.
Let's start off with the Move function. We're going to move in XYZ. We can move View, Parallel, Project, Slider. We're going to take a look at some of these functions here. This is quite a complex command. It is a very long command with a lot of options. But we're going to go through the basics of what you'll be using initially, which is going to be just the straightforward standard Move function. Let's start off with XYZ. I'm going to go into F5, which is our top view. Let's move one of these CVs here. If I pick a CV like this, I can just move with my left mouse button, freely.
It's allowing me to move in X, Y, but not in Z, because I'm in the top view. If I control z this, go into my F8, and if I move with my left mouse button, now into perspective, I'm locked into X. Middle mouse button is Y. Right mouse button is Z. Let's control z out of all of those. Let's go into our top view from the perspective view. Let's make sure that we're in orthographic, which we are. Doing this movement, I can lock either X, Y and Z, as well.
If I was only interested in moving in one specific direction, I can lock, for example, the X, I can lock the Z, and now I can only move in Y. In this case, if I use my left mouse button, and notice that it's moving only in the vertical, which is the Y direction. If I use my middle mouse button, you'll notice that it's locked out of X. Again, my right mouse button will allow me to move in Y only. If I go into the perspective now, left mouse button, X is locked out. Y is fine with the middle mouse button, and the Z, or the vertical axis, is locked out, as well, because that's what I've selected here.
Let's uncheck those. You'll notice that, when I do this movement, it actually can be a little bit too erratic for me. It's moving too much. I can actually dial that down by using mouse sensitivity. If I change the mouse sensitivity to, let's say, 54, now I can do more granular movements. This is very important when you're doing Class-A surfacing. We can also select these predefined values, like so. For this example, we're going to leave it at one. Okay. Let's continue on. We're going to go from XYZ.
Now we're going to go to View. If I rotate, and I'm looking in a perspective like this, and I'm locked into the view now. So if I move this control point, even though I may think I'm moving it on the ground plane, if I go and rotate this part, now you'll see that I moved that control point off the ground plane because I was using the View mode. So just be careful with that one. That can get you in trouble if you're inadvertently in a View mode and you think you're trying to move it in X, Y or Z. Going to move Parallel now. In Parallel, I want to go back into the top view.
With Parallel, I select my first control point. Then what I'm going to do is, I'm going to select a hull. Now, a hull is a straight line between two CVs. In this case, we have a hull right here. If I select this hull, you'll notice that that CV now is moving parallel with that hull. If I select this one here, it's going to be moving parallel to that one, as well. I can use the Project function. Now, with Project, I can select the CV. If I pick this hull now, it projects it onto that hull and moves it along that vector.
I can do the same over here. The next option is Slide. Now, with Slide, what happens is, it takes the selected CV and it moves along the vector that's dictated by the hull between the selected CV and the adjacent CV. In this case, the hull between this point and this point and the hull between this point and this point is the only two vectors that I can move this particular CV in. This is good when you're doing tangency manipulation.
The next one is Normal. With Normal, I can select the CV, and as soon as I start to move, we get an arrow that indicates the normal vector. Essentially, this CV is being projected back onto this curve. Perpendicular to that curve is the direction of that CV movement, like so. Then we're going to be back onto XYZ. Let's do the same for surfaces. On a surface, we can go to pick a CV. Let's go to XYZ so we can pick a CV on this surface here.
With XYZ, I can move vertically, I can move in the Y, and I can move in the X. I can also move in the View, like so. If you're going to be moving in View, typically what you're going to be doing is going into a true orthographic view and moving it like that. There's only no danger of moving it in the missing axis when you do it that way. Okay. Parallel. I can pick this CV and I can pick this hull. Again, the movement is parallel.
Project. I can project it onto that hull. That movement is locked into that vector, as well. Now with Slide, because a surface has two directions, it has a U and V, positive and negative, we have four options to slide this CV with these four hulls. I can slide this direction, this direction, this one and this one. Normal. As soon as I start to move this, it's locked into a normal vector. Again, this point is being projected back onto the surface, and that is the normal vector that this CV is moving in.
Then we're back to XYZ. Let's switch to hulls. Now, hulls are specific to surfaces. So we're going to be focusing on this entity again. By the way, let's shade this up very quickly, so you can see the shape that we're looking at here. It's a reasonably complex shape. Let's go back to wireframe, and we'll cease that off. Okay. We're going to go to the Move command, we're going to move Hulls, XYZ. In this case, if I pick this hull here, it picks the whole hull and I can move right mouse button, middle mouse button, and the left mouse button.
Now, Parallel, if I try to select a entity to move this parallel to, it makes no sense. There are some commands that just don't work with hulls. Parallel is one of them. The other one is also Project. I wouldn't use those two with this command. It doesn't work well. Slide, let's use the Slide command. Now, with Slide, you see we have an option to slide along every one of those CV points. Now, this makes a lot more sense if we're in a top view and a more simpler entity. So let's go ahead and create a Surface, Primitive, Plane.
Let's scale this up, put on our CVs. In this case, I have to activate the command again. You can see we dropped out. Let's click that one time and let's go ahead and pick that hull. So we can pick any one of these arrows, and we'll move the whole hull uniformly, like this. If I pick one of the larger arrows, I can actually twist this hull. It's a lot clearer to see in this particular situation, but we can apply this same principle to the more complex surface. Let's go ahead, activate the command again, pick the hull, and you can see that we can twist or we can move in a uniform direction, like so.
We can move Normal. Again, if I pick any one of these CVs, it doesn't really matter which one I pick. I can pick and move the whole hull Normal. In this case, I'm going to pick this point here, like so. Now, if I try to pick on the actual CV itself, you see it's asking me, which CV do I want to use? There's two hulls there that it's identified. So it's better, if you're going to do this command, to actually pick off one of those CV points. Again, it doesn't matter which one you pick. What it's doing is, it's projecting that control point Normal back onto that surface, and that's the vector that it's going to be moving.
Again, don't pick on the CV. pick on one of the hulls. That will give you the right results. Then we're back to XYZ. Let's take a look at some other options for moving these control points in a more controlled manner. I'm going to take this CV here, and we can go to Move, or I can use this option here. Let's go to CVs. We're going to move in XYZ. In this case, what I'm going to do is, I'm going to pick this CV and I want to hold the alt down and snap it to that grid. Now, these grids are exactly 100 millimeters apart.
We can check that by going to Locators, Measure, Distance. Now, pressing the alt down, I'm just going to pick those two points. You can see, 100 millimeters. Now, this measurement is a locator, so I can just press the l to delete that. Okay. We're going to move this control point in equal steps now. What we're going to do is, click on Step Size, and we're going to lock the step size. Let's lock the step size to 10 millimeters. I'm going to pick this CV. Let's activate the command again.
If it drops out of the command, just activate it by clicking on the Transform CV tool and it will go red. Let's pick this CV. Let's click on Lock Step Size, set this to 10 millimeters, and with the right mouse button, I'm just going to hover above the CV and click one time, and it's going to move it 10 millimeters. So one, two, three, four, five, six, seven, eight, nine, 10. And it's exactly at 100 millimeters. I can go back the opposite direction. One, two, three, four, five, six, seven, eight.
And also, if I hold down the right mouse button, you can see that I'm not allowed to slide it. I can only move it in incremental steps. That's because I've got Step Size and Lock Step Size selected at the same time. If I switch off Lock Step Size, and I carry on clicking, it moves in 10-millimeter increments. If I hold my right mouse button down, I can then slide at the same time. I can slide, and then click the 10 millimeters increments, or slide by just holding that down.
That's the difference between Step Size and Lock Step Size. Proxy Display ... Let's take this off now. Proxy Display, very simply, allows you to see where you're moving from and where you're moving to. That's how you can move in a more controlled manner with CVs and hulls using the Transform CVs options.
- Manipulating views and entities
- Working with layers
- Creating curves
- Sweeping, extruding, revolving, offsetting, and blending surfaces
- Modifying geometry
- Moving, scaling, flipping, and rotating objects
- Trimming curves and surfaces
- Creating copies of objects
- Aligning, combining, and splitting objects
- Analyzing geometry
- Shading models