- Building and detailing a space helmet
- Making a flexible duct
- Building details on round pipes
- Modeling organic objects
- Using the SrfSeam command to move seams out of your way
Skill Level Intermediate
- [Instructor] In this next demo, we'll build a beautiful space helmet and in a later demo, add some cool details. Along the way, we discussed how to work with seams which occur in both curves and surfaces. Let's take a look at the finished helmet here in this perspective viewport and you can see this seam I'm talking about right here. A seam is basically on the surface, in the interior edge so it won't occur on the exterior but it's captured internally. So, we'll discuss several ways to move those out of the way if they interfere with your work.
Also, you might notice if we look at this from the top, it's not around. So, we're going to to jump over now to start building this and we will use an ellipse for the revolve. It's little bit different but it's very cool and easy to use. One thing to note, if you're going to build your own geometry here, this is a degree three ellipse which is not the default. If I turn on the control points with F10, you notice there's many more control points than your normally see. So, you can build it either with the ellipse deformable option or with a normal ellipse and then do the edit rebuild.
Let's turn the control points off with F11, I'm going to make sure I've got the correct O snaps on here. I've got the end point intersection and perpendicular that will get me going good. So, let's go to the front viewport, zoom out just a little bit. I do want to keep my perspective open here so I can make sure I snap right on that intersection. I'm going to draw with a control point curve. I'm going to start at that intersection. I could also start this in perspective, that'll work just fine so I click there, looks like it's snapping correctly.
However now, I want to make sure to keep this clean, I'm going to go up perfectly straight. So, I'm going to hold down Shift. Now, we can zoom out just a little bit more and make this helmet profile. The last thing I want to do is hit that edge again perpendicular so we do that with a perpendicular snap which is already on and so that should come over perfectly 90 degrees from the last point I selected, and if I want to turn it back on with F10, you can verify that because these two are perpendicular to the edge where they stop or the axis where they're going to be revolved.
Now, we're ready for the first surface operation. I'll turn them those control points off with F11. So, like we mentioned it with revolve, this is very similar command. I'm going to go to Surface and right below Revolve is Rail Revolve. We do have to select several items here. So, it's important which order you pick but just watch the command line to be sure. The profiles, the curve we just drew. The rail is the ellipse and then we need an axis. So, I'm just going to use the snapping here at the origin and then that point that we ended with at the top.
Okay, let's double click Perspective and inspect what's going on here. Now, you'll see, this is our original curve, I'm just going to hide it for a second, and we've generated a seam. Now, this will be a problem. I'm going to show you exactly why and then we'll do this more than once. So, let's go ahead and just assume we're going to build this visor section here. I'll do that with another control point curve. One tip that'll help you make cleaner geometry especially in these offset areas is try to cross at 90 degrees.
By that, I mean I'm going to go right through that edge and make it rounded and then exit also at 90 degrees. So, this would be very sharp, that's kind of the opposite direction, and this is relatively 90 degrees through and just pass right through. Okay now, that's kind of inside there, that's fine, we're going to use the project command and get this curve onto the surface and then we'll talk about this pesky little seam and how to get rid of it. So, I want to use the curve from object.
If you don't have this toolbar open, you can also go Curve From Objects and Project, the very first command. You do have to be in the correct viewport because the grid will tell it which direction to go, reading the command line, it says, "Select curves," that's just the one we drew, right click or Enter, and then pick the surface. Now, as soon as I right click to accept, you'll see what happens in perspective. It projects both directions and maintains the same shape and it's closed, so it's really nice.
Now, we've got a surface to trim or split. Let's do that and look what happens with the seam. Split this over here on the left or main toolbar. I'm going to split the overall helmet, right click, and then select that curve. Remember, when you project, it's guaranteed to touch. That's why it's really handy. Okay, looks like it's split out and if I rotate around here, you will see the problem. This is two separate pieces. So, why wouldn't we move that seam around to the opposite side where we have no detailing or objects happening? Let's do that right now.
I'm going to go ahead in hit Control + Z a few times I just undid the split. I think, that's all I need to do, it's just one time. So, here's the seam. The command to move a seam especially in conditions like this where it's inside the surface. We can go to the Surface, Surface Edit Tools, and Adjust Closed Surface Seam. It's asking me to select the surface and the seam is now able to move anywhere I wanted to go.
I'm going to snap it over here right to the back and you'll notice, it is away from all the work I just did. So, we can go ahead and do the splitting and offsetting as I'm about to show you and we don't have things breaking into different pieces. That's the first way to move the seam, the surface seam command. I'm going to actually show you a second way before we go any further. So, I'm going to the surface and delete it. I'm also going to delete this projected curve there and we'll maximize the perspective viewport.
So, we just talked about seams on surfaces, let's talk by the equivalent of seams or end points as they're sometimes called on curves 'cause they actually tell the surface where the seams will fall. So, let's select this ellipse, I'm going to go to the Curve menu, Curve Edit Tools and there's a very similar command to the surface one, Adjust Curve Seam. You'll notice it's over here which is the spot that causes all the problems to begin with. Let's just take that point and just drag it and then snap it to the rear side.
Right click when you're done. Now, we should be able to repeat the command and get that seam exactly where we want it. Surface, Rail Revolve, we have a profile, we have the ellipse, we're going to define the axis here and there it is, the seam is now right back. It's not super obvious but it's right there underneath the curve and that was all generated because of the seam on the curve. You definitely notice is not in the front. So, we're finally ready to go ahead and continue the visor detailing here.
We want to switch to wire frame view, that makes it easier to see. I'll draw that line again. Again, we're going to try to keep it going through perpendicular if possible when we cross and go outside. It looks pretty clean. Let's go ahead and get that projected, I'm going to select Curve, Curve From Objects, Project, here's the curve right there, right click to accept, select the helmet, right click again, and now, we're just about done.
So, we've got that curved back on the surface, the seam is on the back and not going to interfere. So, we go ahead and do this split operation. We're going to split the helmet, right click, and then pick the one curve, accept. So, there's one nice clean piece and now, we finally get to my favorite part of this process. We're going to leverage existing geometry here to create an inside face and an edge at the same time. We'll use the surface offset command with a couple of modifications.
Surface, Offset Surface. One of the questions we have to answer here is which direction I definitely want to go in, then, I want to make sure the distance equals 10, so go ahead and change that if it's not defaulting to 10. Typically, it'll be one every time you reboot the computer and every single time, you will have to say Solid=Yes, that will default to No every time, and it looks like we're ready to go. So, I'll just right click to accept. When it completes, you may be initially confused but trust me, this is going to be a fantastic process here.
We have got a solid piece of geometry because the offset, we have a second surface, and because of the solid option, we have an edge. So, there's two of the three we actually need and it's a simple process here, just to remove the exterior. I tend to go with this command here, not Explode but right click to extract. So, we're going to select that outside piece now. So, we only used it as construction or temporary geometry. So, I'm going to right click to accept that and then hit Delete.
There we go, we've got this beautiful offset with edges going down perpendicular from every single position all the way around the perimeter of that visor. Let's go ahead make one more detail here. I'd like to make a fillet or chamfer along this edge. Actually, now that I think about it, there's so much curvature going on here. Let's just contrast that with a chamfer or square 45-degree edge. To do so, I typically will join these together, use the solid command.
so select both or hit Shift to add them. Control + J is the shortcut to join. You can verify that just because they all light up. I'm going to go to the Solid menu, Fillet Edge, and Chamfer's located right inside there. We have several options grouped together but in case you didn't know where Chamfer was, it's buried under Fillet. Select Chamfer Edge, I'm going to modify the distance just a bit from the default of one, I'll just pick three, and then we'll go around this edge right here.
Just in perspective, it's really handy 'cause I can now move around a make sure they went continuously and there's no gaps. Looks like it's complete, so I can right click, and get the previews. Again, this is a lot of geometry so it's going to take a bit of time to calculate, and it also seems a little bit messy, that's actually not the case. We have a lot of isocurves here. So, if you want to get a better or cleaner view, you can just select them again and come down here to Isocurve, just turn them off.
It should look pretty close to the original example that we talked about the beginning of this demo. I'd like share one final tip here. A lot times when students are building stuff, they tended not to make as many changes as they should because it's a complicated process and they don't want to go back and mess it up. Here is a great tip to get away from that situation. What I'm going to do is I'm going to separate some of these parts here and then show you an amazing way to untrim the original geometry. It should save you a ton of steps.
So, I'm going to go back to the Extract which is right click on the Explode. I'm going to zoom in here, I'm going to pick that chamfered edge, right click, and now, I should be able to select all those separately and if I want, just move them away. The point I'm trying to make here is that anytime you have a surface that has been modified, Rhino always remembers the original components, and we can get them back. So, what I want to do here is right by Trim, use the right click for Untrim, pick that edge, and Rhino has found it, put it back in place.
So, I can make additional changes and tweaks. So, two things to remember. First, the ability to experiment is critical. Don't forget to use the untrim when you want to go back without rebuilding from scratch. And second, when working with organic shapes, use the surface seam or curve seem to get that seam out of your way.