Join Veejay Gahir for an in-depth discussion in this video Keypoint curves, part of Alias Essential Training.
- I want to show you another very powerful curve creation command and that's called the Keypoint Curve. So let's open up Keypoint Curve Toolbox and we're going to start off with the very first one which is circle. So let's switch to a true top view and with circle selected, let's double click that. You can see they're very simple options and we're going to go with the default settings, say Go, and the first point is going to specify the center of this circle. So I can hold my alt down and we can snap right to the center of the grid like so.
Second point allows me now to specify an exact radius so the value changes as I move my cursor. I can also open up my Information Window which is Ctrl+5, and if I look at the Information Window, under Attributes I can also specify an exact radius like this. So this is a very powerful command and it allows me to have full control over this particular entity. I can also pick the entity and scale it, like so. I can also pick one of those keypoints and drag it.
Now, you have to use this icon here to Drag a Keypoint so let's pick this icon and let's just drag this keypoint and it changes the value of radius for that particular circle. Now, one thing you want to try to avoid here is using Cv/Hulls to modify the shape here, because as you can see, if I pick a Cv, and move it, you're going to basically distort the shape. And if I go back into my Information Window, pick the actual circle here rather than the Cv, you'll see that the ability to change a radius has disappeared because it's not a true circle now.
Okay, so let's move on. With Ellipse, again, very similar, very simple default settings and we're going to go with that. First point and then second point, so major and minor axis are completely editable so if I now go to my Information Window, there's my Major Axis so I can dial in a value there, Minor Axis, I can change as well. Again, I can use the Drag Keypoint option to change the size of the ellipse and change the major and minor axis as well.
Alright, so let's delete that. Let's go to the next one which is rectangle. So with rectangle, first digit, second digit, very, very simple command and again under Information Window I can change the Width and I can change the Height as well. Now you'll notice as I'm creating these keypoint entities, we're getting these grey lines appearing and these are called guidelines. So when I create an entity using this particular function, Alias will create a guideline, and essentially it's just a way that I can snap to a specific point that's already been created from a keypoint entity and it just helps me align my data effectively.
So let's delete that data, but you'll notice once I delete that data the keypoints disappear too. Even when I delete the entities, sometimes the guidelines will remain and to delete them, very simply go up to Delete Guidelines or the hotkey G which we've setup before. Okay, so move on now to the arc and this is one of the most useful functions that I use and that's the 3 Point Arc so if I double click that, again, very simple options, first point, second point, third point. And you'll notice now that it's snapped to one of those guidelines, so the guidelines are useful but they can become a little bit of cumbersome at some point.
So in this case here, I'm going to delete these guidelines just by pressing the "g" command. Go up to the Information Window, again I can change the radius value here, let's make it 1000, like so, and also I can use the drag function to change the radius as well. Let's delete that. Let's look at the next option which is this one here, double click, so Arc with 2 Points. So let's say go to that, and there's the arc with 2 points.
Again you can change the value using the Information Window. Now you can see these guidelines appearing here, now this guideline here is tangent to the end of this arc, and this guideline here is tangent to the end of this portion of the arc, and also this one here is perpendicular so I can now go ahead and specify another point right on that guideline and let's say another one on that guideline, and then I could put a radius in here. Again, it's just to help you create data but sometimes you may not need them and then just very simply press the "g" command to delete.
So moving on now, we're going to go to the next option which is arc 10 so double click that. So this is creating an Arc Tangent To Curve Options. Now, sometimes it's very difficult to try to remember all these options and even I struggle sometimes and it's just a case of understanding that you can create the entities and you just have to go and find the right icon within the Keypoint Curve Toolbox. So this one creates an Arc Tangent To a Curve Option, so let's see what the prompts are telling us. So the first prompt says Select a curve at location to make the arc tangent from.
So it's kind of helping us a little bit with the information that we need. So first of all, let's go ahead and create a circle like so. Let's go back to this option here and let's pick a point on this circle, it's looking for an arc or a circle. The next option then would be to pick a point out here like so and you'll notice what it's doing is actually creating an arc that turns into that initial entity that I selected. So delete guides, let's move on now to this one here which is the Concentric Arc Options which really is a parallel function.
So let's say go to that, so select an arc to make our concentric to. So let's pick this one here, and then we can pick a point out in space and then we can specify a region of that offset circle that we want to keep. So again, you can see how these guidelines can gather very, very quickly, press "g" to delete. Let's move on to the next option here, which is line. So double click, again, very, very simple option, let's say go, pick one point, pick the second point and we can also snap with the alt function.
Again you can go to the Attributes and you can change the Length to an exact value. Let's press "g" to delete those guidelines. Let's go to the next one which is polyline. Again, very simple, it allows me to create a continuous polyline like so. And this is where the guidelines really can help you create 90 degree corners like so. Okay, we'll delete that. And we're going to move on now to parallel, parallel, again, very simple.
Pick an entity, pick a parallel distance, and then pick a portion of that parallel line like so. Let's delete the guidelines. And angle now, so again, look at the prompt box at the top there, it says, Select a curve to make line at angle to. Kind of confusing but what it's asking you to do is select a line that we're going to create the angle from. So this is the line that I've selected and this is going to be the angle. So let's go to our Information Window and let's see what we can do with that.
So you can see that the Angle here is 322, let's make it 300, like so, let's press the "g" to delete guidelines, now let's clear up this work space a little bit by deleting some of these entities. So the next one we're going to move on to now is this option here, which is creating a line tangent to or normal to an entity. So let's double click that and let's see what the terminology is for that. So in this case there are no options so we can't really see what the command is but let's have a look at the prompts at the top.
So if we click this one time, it says Use a mouse or enter a start point so we can pick a start point here. Now in this case, it's not asking for a curve so we can pick a point in space. Now it's telling us to Select a curve to make the line tangent to. So let's make it tangent to this circle. So really what it's doing is creating a line and it tans off on that circle, at that location, nearest to where I digitized that point. Let's move over to the next option. So, you can see by the actual icon, we actually do need to have two circles here so let's go ahead and create another circle like this, and let's go to this option, Select a curve to make the line tangent from, so let's just pick this one here, and we can also then pick this curve here.
We can go from this side to this side as well. And the last one is perpendicular. So in this case we're going to make a line perpendicular to an arc. So it says, Select a curve or a surface curve to make the line perpendicular on. So in this case, we're going to pick a point on this curve and then we can pick a point out in space, and then that will be 90 degrees or perpendicular to that particular curve. Let's delete all of these entities. The next option we have here is this one here which is arc.
It's not specifically just an arc, it's labeled as arc but really what it does is, I go back over to it, it's the Line-arc Tool. Okay, so with the Line-arc Tool let's just use the alt and we're going to snap a line like this. And now what I want to do is I'm going to create the third digitized point and that creates a circle that tans nicely from the end of that specific line and I can always hold the alt down to snap to a gridpoint, like so. Then I have the option to use the guidelines so I can use this guideline and create a line like this and my next line will help me setup my circle, so you can quickly build a profile like this.
Now, again, I don't really use this. If I'm going to create something like this, I'll create separate lines and then fill it so it blends in between the two. Nevertheless, it's an option that's available. Then you can always go ahead and break these at any point, so if I say break to pick a point, I will break those keypoints accordingly like that. Again, we can use the drag, and we can change the shape of this particular line arc like so. So that's Keypoint Curves, very useful because you can always go to the Information Window and change the attributes of those particular entities.
- 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