Join Veejay Gahir for an in-depth discussion in this video Tubular Offset, part of Alias Essential Training.
- In this video I want to show you another function called tube offset. So let's go to surfaces, rolled edge, tube offset. Let's take a look at some of these options. First of all, let's zoom in to this front cluster of surfaces and we're going to set the value for tube offset at 50 millimeters and the surface we're going to create a tube. So let's pick the edge. We've got chain select on and auto-update as well. So very simply, what happens here is we just create a tube. We're using the edge of that profile and it basically sweeps a circle around there like so.
Now we can take this and we can change it from tube to a groove. Now you'll notice it fails here because you can't create a groove from an edge. We have to have some real estate inside of this particular set of slabs. So let's undo that and let's go ahead with groove and pick these curves on surfaces. Now you'll see with groove we have the option to create this type of data. So let's shade that up. Now with groove we can flip that groove to the outboard portion.
We can just click on flip here, and it will flip it outboard like that. So again, remember we can't use groove with this particular type of data here. We have to have real estate inside. So undo that. The other option we have is none. If I pick these curves on surfaces, what will happen is it will generate these curves on surfaces for me, but no surface data. So I could use these for my rails if I'm doing a sweep command. So let's undo that. I'm going to go back to tube and I'm going to go ahead and pick this edge here like that.
We've created our tube. Now we've got some other options here. If we shade this, I'm going to take my tangent offset and I'm going to slide that to a value of one, and I can slide it to a value of minus one. So what this does here is it takes the value of one, which is 50 millimeters, and it's basically slid this tube so that it starts right on the edge of that opening. If I change the value to one, it slides it along the surface 50 millimeters like that. I can also at the same time change the normal offset from a value of minus one to a value of one like that.
So in this case, I want to change the normal offset to a value of minus one, which should be -50 millimeters. Let's say next to that. So let's go ahead and shade this. Now you'll notice that we have a slight discrepancy here. This data is poking through those slabs at the top. So if we've offset this value of one, which is 50 millimeters and inboard 50 millimeters, why are we getting data poking through at this portion here? Well the reason for that is that when we execute this command, the normal vector that's used is from the edge that's selected.
So the normal vector from this edge here is very different to the normal vector that's 50 millimeters along this surface. So if I go to wire frame, and let's just click on normal vectors, these are normal vectors that show you the direction. So you can see that this normal vector, which is the one that's being used, is very different to this vector here. I'm going to delete this tube. By the way, I'm going to show you very quickly how I set those normal vectors up. So let's go ahead, pick those two surfaces. First of all, clean up this data here by just taking these curves on surfaces and deleting them like that.
So if I take these two pieces of data like this and go object, edit, offset, I can offset that data inboard, I can offset it outboard. We're just going to go to a value roughly like this and then press the space bar. So now what we've got here is two offset surfaces like this. Let's delete the original vector data like that. What I'm going to do now is I'm going to very simply create a line from the end here to the end here. That's the normal direction. We can do the same for this portion here.
These are the curves on surfaces, so control alt, pick that, pick that. Now I've got the two vectors set up. I can just simply delete the offset surfaces, and that's my normal vectors for those surfaces. Now again, just to demonstrate this very clearly on this set of data, I want to select this data, hide unselected, and if I go to the back view, you'll notice it comprises of two surfaces. This surface here is completely flat, so the normal vector for this point here and the normal vector for the offset inboard is going to be exactly the same.
This one here obviously is a curved surface, but they are tangent. So let's go ahead and create the tube offset again using this data. So under surfaces, rolled edge, tube offset. So we're going to pick this edge. Let's shade that up and make sure that it's going in the right direction. Which it is. If I say shade now, you'll notice that again, we have some protrusion through the top here because that normal vector and this one are different. But down the bottom here, the two normal vectors are exactly the same.
So we have very little if at all any protrusion from that tubular surface.
- 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