Join Dave Schultze for an in-depth discussion in this video Prototyping part 4: Closing the model, part of Rhino: Tips, Tricks & Techniques.
- [Instructor] Next up we continue from prior lessons where we decided the design was ready for a 3D printout. I made a second copy of all the surfaces, put those on a new layer, named it Prototype, and now in this video we focus on closing it up. Right down here we can go ahead and just, since that's already off, go ahead and collapse that down and keep it out of the way. Now all work on that layer group design is turned off and left alone for this demo. Let's maximize perspective view port by double clicking, and first I want to talk about the goals here.
We want to connect all the geometry along its edges to make sure it's closed or joined into one single piece. That means there can be no openings. Openings typically are manifested as naked edges, or even worse, naked points. Any of these problems we find will be addressed in later videos. In this video we're going to talk about just closing stuff up. So, you'll notice when I click on the penguin there's some different parts here. Before we go ahead and try to join those, there's about four different ways you'll notice on the screen, let's revisit some definitions.
So, this box is obviously opened because you can see the top, but it is also a polysurface, which is defined by having multiple surfaces joined along one or more edges. So, you'll notice when I click on it it lights up, but there is no cap or top, so it is an open polysurface. The reason I point this out is because closed polysurfaces also can be technically called solids, but the thing a lot of people don't understand is you can go back and forth. You can extract or explode a solid and work on different parts and then rejoin it later.
So, to quickly demonstrate this I'm going to pick this lid here. We'll do the Rhino move command and we're going to snap from the endpoint to the endpoint. That should be perfectly aligned up there. Now, nothing has happened and I want to point out another mistake a lot of beginners make, and that is they will group stuff together, pick a bunch of parts and group. So, that is the wrong process for prototyping. Obviously you can have stuff in a group that doesn't even touch along edges or endpoints of a line, so it's important to first un-group in the scene.
So, back to this example, we've got the top. It should be in perfect position, and if I pick the box by hitting down Shift, I can now join them because those edges are perfectly shared and touching. We can use ctrl + j on Windows, cmd + j on Mac, or little puzzle piece here. So, you'll notice it kind of blinks. If you look at the command line at the top it says two surfaces joined into one closed polysurface. There's another quick way to tell if things in the scene are also closed or open.
You can select them and go over to the properties panel. It'll tell you immediately whether it's closed or open. With those definitions out of the way, let's proceed to closing up our penguin model right here. I'm going to show you four different processes and it all depends on the current state of your geometry. We'll start with some of the trickier ways and then work our ways down toward a Boolean Union, which is definitely the easiest way to join stuff up. Now, over in this eyeball section we've got some geometry overlapping, so I'm going to go ahead and just pick the penguin surface here and hide him temporarily.
The ctrl or cmd + h will get that out of the way. Now, I'm noticing that I've got this surface here separated. I remember I split it out and I used that for texture mapping. For prototyping we can't have this condition, so I'm just going to delete these little floaters and we can close it back up very easily. We don't need a join, we end up with an extra seam. I like to make this a little more clean. So, I'm going to go over to the trim command and right click to get un-trim, so amazing we get to close stuff up.
That's a really cool technique. I've mentioned it before, but people are always amazed and seem to forget. So, you can always... Anything that's trimmed back you can get the original part restored. So, that takes care of the eyeball part. We still have this lid part. Now, I'm assuming I was pretty careful here and these guys touch on the inside along that edge, so I should be able to pick both and just to be a little fancy I'm going to pick the other one, too, and I'm going to run the join command right now.
So, these two will not be joined together. Just edges that touch, so this is a really cool way to speed things up if you've got a lot of repetitive elements in the scene. So, again this is ctrl or cmd + j to join or we can use the puzzle piece. Looking at the command line, four surfaces joined into two closed. So, we're in great shape so far. Let's right click on the light bulb to show the original geometry. I think it's pretty important not to use the hide command too much. If I need something away for a long enough time, definitely move it to another layer and turn that off because it's too easy to forget where stuff is.
Okay, our second way to connect stuff is down here at the beak. Now, you'll notice that the penguin overall is open and this beak part here is also open. You can tell there's an opening on the inside, but I was smart enough to get these two surfaces to completely and totally overlap. So, you'll see that right there on the side view. Now, since they're both open I could do a Boolean operation. That's usually people's first try. However, if the surface normals are not in agreement, our union will end up having a subtraction.
So, to avoid doing this multiple times, which you can do if you like, I prefer to use the split-split operation for anything that's not entirely closed. So, let's go ahead and click on split. Now, before I start I'm going to split the first part, A to B, and then just reverse, repeat, then split B back to A. If they both completely overlap it is a perfect solution for any two entities that overlap. So, let's go forward now, split A, right click to B, let it finish.
Right click now, since we're outside the command, which will repeat the command, and split B back to A. So, I'm right clicking it each time. Now it tells me at each step the surfaces of the beak and body, both split into two parts, that tells me successful. You can also zoom inside here and just check it out. So, there's the overlap I was talking about earlier, and these pieces can now be deleted, so any overlap, just get rid of it. So, this is a process we've talked about many times in modeling.
We call it split-split, throw away the garbage. So that means our final step is just to select either of them, then select the other side, A and B both, and we can join them up with the cmd or ctrl + j. Okay, those are joined up and they're still open, so we're not done. We're going to move on to number three. This is a super simple, we're getting easy now. Super simple way to connect stuff. So, this looks like this little flipper was blended to the body, they're all separate parts.
Blending typically does not connect them, so we can just Shift pick all these pieces here and cmd or ctrl + j to join. So, interesting, it says that we are now closed. So, let's reexamine that, we're going to click on the body. Looks like the beak and both little flippers are joined. The eyeballs are not, also the feet are not. So, we'll save that for the very last technique, which I find the easiest to use.
So, we're just going to select... We'll do this in actually a couple stages here. I don't like to throw too much at Rhino. Just kind of take my time and if there's a glitch then I don't have to go back quite as far. So, I'm going to Shift and click on these three parts, two feet and body. Then we go to the solid menu, we have Boolean areas down here and we're going to do the Union. Okay, it does take a little bit of time, and now all that stuff that was generously overlapping is now trimmed or Booleaned perfectly.
You can also double check if you like to do this. Just come inside here and there's the void for the feet inside the body. This could look kind of weird, seeing stuff inside out, so I only do that as a last resort just to double check. Now we've got the eyeballs up here, I think those are the last things to check. Let's pick both of those, Shift click, Shift click so we've got all three parts, and to make things a little bit quicker you can always go up to the command line and that should be the last 10 or 15 things you did.
If I can just pick that, usually it's faster. It's a little bit of processing and now that should be one closed surface. I am noticing the properties tell me it's open somewhere, so the property dialogue is telling me there is an opening. I'm not seeing it, but I have a suspicion that it's probably a naked edge. We're going to cover that in the next video. Let's just wrap it up by saying the requirements for designing and rendering models versus prototyping models are almost the exact opposite.
Design models can be open or even incomplete since you usually view or render them from one side. Prototyping, like we're doing now, requires a lot more care, as we'll see in the following videos where we begin to explore and fix a few of the more common problems.
- 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
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