Join Veejay Gahir for an in-depth discussion in this video Additional notes on sweeps, part of Alias Essential Training.
- In this video, we're going to discuss some situations that you may well come across when using the Rail command. Let's zoom into these entities here. Let's open up Rail, and I'm going to select Generation Curve one, Rail one. So we're in a monorail situation. We're going to pick the generation curve as this one and the rail is going to be this one here. Very predictable results. No problems there. We're going to undo this. We're going to pick this as our generation curve and this curve here as our rail curve. You'll notice the generation curve jumps to the location of the rail curve.
Now, if this is not what you wanted, you want to hold the position of the generation curve, all we have to do is go to Fix Curve and click on Generation Curve as the fixed curve. Now, this solution only works when you're using monorail. You can have a gap with monorail, but you cannot have a gap with birail. Let's take a look at this. In this case here, we're going to go with two rails with one generation curve. Here's our generation curve. Then we can go with primary rail here, and this is going to be our secondary rail.
Again, predictable results. No problems there. Generation curve, rail one, rail two. Now we have an error. Alias is basically telling us, "You've got a gap between these two entities. "This is not going to work." Again, when you're in a birail mode, you cannot have a gap between your generation and your rail curves. Let's undo that. Let's take a look at this scenario here. If I shade this model up, you'll notice that this model comprises of separate entities.
We got one surface here. We got one surface here. Another surface there, there and there. And they're all broken at different locations. Let's go ahead and see what we can do about this. If we go back to wireframe, and I'm going to open up the Rail command, we only have one generation curve, but we have two rails. There's not an option within this command to have two-plus rails. So let's see what happens. We're going to pick this as our generation curve, going to pick this surface as just our rail one, and this one as rail two.
We can switch on Continuity Check. You can see that we've matched with positional continuity here. But the surface itself is a pretty undesirable result. It's skewed over like this, and that's because rail two and rail one have different lengths. Now, what we can do here is, we can click on Curve Segments. You'll notice that these little markers appear. I can change these markers by just dragging them back, like that. So at least we've got some sort of a rail configuration now for this particular distribution.
Now, at the same time, we can change this to tangency. Now, I can go with Rail one, Tangent, Rail two, Tangent. Or I could just go straight to the top and say Tangent. Even though there's no surface for the generation curve, it doesn't matter. Alias will ignore that command, but it will apply tangency to rail two and rail one. And we've matched tangency here, so that's quite a good result. Okay. So let's zoom out a little bit here. We're going to go with Next. With Next, this is going to be now our generation curve. This is going to be our rail one and our rail two.
Again, we have a very strange result because we have a skewed surface here. But we can take these curve segment points and drag them back. You'll notice as I get back to more of a radial type of distribution, the surface jumps into a single span, rather than a multiple span like this. So this is a better result for us. What I'm doing here is just eyeballing this into a nice, even distribution. Let's go with Next again. We're going to pick this as our generation one, rail one, and rail two.
Again, this is a very strange result, but we can fix that. Let's take this point, drag it back to here, like so, and let's click on Next. That's our generation, that's our rail, and that's our rail two. Let's go back to Top. Now, you'll notice that we've added a segment in here. Let's see if we can remove that extra segment. Right now, it's two by one. One of the ways that we can do this is, we can go back into one of these surfaces.
It's probably going to be this one here, because this is the generation curve for this surface. Let's go back in and do a query edit. We're going to pick that surface. Let's go back and let's see what we can do with these curve segment points. I can play with these curve segment points, and there may be a point where I can actually reduce that segmentation. But it doesn't look like I can achieve it there. This is as far as it can go, so that's going to be the best we can do. But it's not a bad result. We have two segments here, on this surface, but everything else is single segment.
Let's go ahead and delete those locators and just check them again, just to make sure that everything is green. Press l. I'm going to go into this view here, pick Objects, and just for sanity check, I'm going to go and click on my CVs. And that's what I'm looking for, is a nice, even distribution. What I don't want to see is rogue points flying off into space, which can happen quite easily in a command like this. In this case here, we're going to go ahead and just shade this model up. That's our basic shading. We can go to horizontal, vertical shading.
That doesn't look too bad. And then we can also go to a little bit more interrogation, with higher-quality shading like this. Finally, we can go to visual state shading. This is a pretty good result. But we could go back in there and redefine those curves and rerun this at a later stage. But for a concept, that's quite acceptable.
- 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