Using Meshmixer's automated fixing techniques - Meshmixer Tutorial

- [Instructor] Let's talk about how to fix, in an automated way, downloads you get from online. So let's say we're looking around, and you have a resin printer, and you find this calibration block that I happened to model for another resin printer that I was trying to calibrate. You think, oh this will be a great thing for me to test out, let's download it. So you download the STL, and you bring it into Meshmixer, and Meshmixer shows it like this. And so it has some errors right off the bat. If you don't see these blue lines, or they're hard to see, or they're not showing up as you see them here, if they look something like that, just make sure that your, under shaders at the very top here, under the second shader over, which is just the default Meshmixer shader, which shows these pink faces, and the gray faces. You've seen in some other videos that the pink faces are the inside of the model, and the gray faces are the outside, so we don't want to be able to see any pink at all. So there are some issues with this. Now, some automated fixing techniques may or may not work. If you press the W key, W for wire frame, you can see that this model is very, very simple. Meshmixer doesn't really like simple models, so we'll see if the automated techniques actually work with this. Now we have a couple of issues with this model. This area right here is just empty. This is completely missing the top, so we're going to need to fix that. And if we zoom in here, I'm going to hover my mouse right here and press the C key, C as in center, which centers my view right where my mouse is, and now I can zoom in. You see that there is actually a face here, but because this is blue, this is an open boundary. So there might be something else going on inside. A good way to do that is to see, go into shaders, go to the right one here, which is the x-ray shader, and drag it in, and try to look around and see if there's anything else going on. In this case, there's no other inside geometry, so this might be a really good case to use some of the more easier tools. But sometimes your model is so complex, it's really hard to see with that x-ray shader. So you can, just in kind of an easy way, go into this select tool, and select the areas that you want, and then just hit the delete key. And it'll delete it, and you can see if there's anything else kind of intersecting inside of there, and when you're done, just go up to actions, to undo. You have to, maybe do that a couple times to get it back. And then clear the selection right here. So there's nothing really bad going on here. So let's see what the automated tools do. If you go into analysis here, to inspector, some things will pop up. Now this blue means an open boundary, and the blue means an open boundary here, and the pink means this is an object which falls under the small threshold, therefore it would be deleted if you clicked this pink button. If you drag this down, you can actually turn it into an object where it will try to make it solid. But for something like this, it'll be kind of a bad effect. And I'll show you why. So let's try to click on this. So that's pretty good. Meshmixer did a really, really good job at closing the top off here. But now, if we try to delete this, and fill this in, it actually did a good job with that as well, but there's an easier way to do that. In some models, this can be a really hard thing to fix. Because Meshmixer has to kind of guess where to put geometry when there's already geometry there. So for something like this, it's always kind of good to go into edit, to close cracks, so edit right here, up to close cracks. So watch this triangle right here as I say close cracks. It just disappears. So as I always say, it's always good to go into analysis, let me actually undo that close cracks. It's good to go into analysis and inspector first, but don't always think that that is the best tool to get things done. This is just a shortcut showing you obvious issues in your mesh, but you don't actually have to click these when there might be other options that are better. So in this case, the close cracks command, and I invite you to go look at the close cracks specific reference tutorial, but it says, I'll zoom in here, that this line, this edge, and this edge, from here, are in exactly the same place. So what you do when you go to edit, to close cracks is, it just merges those two into the same. It essentially welds those two together. And you get a much more predictable result than in the inspector where you had to delete this entire thing, and then refill it. The inspector in this case worked pretty well, but in lots of other cases, you maybe don't want to delete it and refill it, you just want to weld those together. So that's always a really good thing to try if you want those things to be closed. This is a whole nother ball of wax. So if we go into analysis, to inspector, Meshmixer does a great job at closing that off. That is how you should start evaluating all models. Make sure that you're in the default mode here, the default shader, and then go to inspector. If you have some issues with your mesh, like something like this has a flipped normal, right, so this is now the outside facing out. If you go into inspector, the inspector won't show that that's an issue. Because technically it still is a proper mesh, because it goes from the outside, it flips to the outside on the other side of this, and then back to the regular orientation. So if you have a whole bunch of flipped normals inside of your model, that is not going to show up in the inspector. We'll need to do something with that later. So that's why it's really, really good to be in this Meshmixer shader, because these other shaders have an inconsistent kind of look with flipped normals, and it's kind of a weird effect. It's always good just to kind of train yourself to look for that pink color. And that pink color is a flipped normal. So we'll deal with a little bit more advanced techniques in the next video, but this is how you would kind of start off your evaluation of models you get from online download sites.