3D printing for an architectural model

If you're 3D modeling an architectural model and you are running into a fragility issue when trying to upload this video goes into detail about how to fix fragility and thin wall.


Jessica : Today for Ask a 3D Designer is… There are a couple of things which are different about today. We are actually utilizing Google Hangout for the first time on Ask a 3D Designer so this is a very interesting kind of change. It’s going to be a little bit smoother and easier for other people to use, and we love to hear your feedback after watching the replay or while live streaming. If you have any questions, you can definitely utilize the questions up in your top… it will your top right. It’s six boxes and if you click on that there’s an option called Q&A. You can go ahead and enter any question that you have into that box and we’ll be able to answer them. I would like to introduce myself! My name is Jess Hedstrom, I’m a new community manager for Sculpteo in the US, and I have only been with Sculpteo for about a month now and I’m very excited to be with the community, and learn more about software when it comes to 3D printing. So, Alvise do you want to introduce yourself?

Alvise : I’m Alvise Rizzo, as every week I’m the product designer of Sculpteo, so welcome everybody to the new Google Hangout webinar.

Jessica: Awesome, how do you like it Alvise so far?

Alvise : Ah, it looks great for me!

Jessica : Yeah it’s pretty sweet right?

Alvise : Yes, sweet!

Jessica : So, just a couple pieces of news before we get started in the model that we’re gonna be kind of fixing today and answering questions about. The first thing I want to tell you about was a couple of blog posts that we have on the Sculpteo blog. The first one is MyDrivingPal , it’s actually a prototype that a company utilize Sculpteo to make, it’s a smart tracker while keeping all your information private, so it’s a really cool story, kind of goes through the arc of their kind of business model so definitely make sure you check that one out. We also have “4 things every power user does”, and so these are 4 tips that you probably want to check out and make sure that you’re doing, if you’re not doing them… hum, it will definitely help you level up in your skills, your modeling skills and also printing skills.
So those are just 2 of the blogs that I wanted to point out, we also have a Linkedin group, so if you’re on Linkedin, please definitely check this out. You can just search Sculpteo and you’ll be able to find our group. Our group is pretty active, answering one another’s questions, and really kind of just chat and share links about the cool things that they are up to. So that’s an another way to kind of join in on the Sculpteo community.
So now that all of that is on the way I’m gonna pass it over to Alvise and he’s going to tell us all about this model and where it came from and what it is.

Alvise : Thank you Jess. So first of all I’m going to share my screen *shares the screen* And you should be now seeing the Sculpteo’s homepage. I want to go through the whole process of uploading of this file. It’s very quick it’s just “Select File”, so why not showing it again? So it’s an architecture model and the name of the file is “architecture model”, I named it like this. I zipped it before to compress it for faster upload. It’s a good way to do that. You will save at least half the time in uploading the files. So, why today we are working on an architecture model? We are having a bit of issues from time to time with this kind of files in our printing process because there are many architects and architecture students that want to prototype their models and sometimes have issues because all what they do is scaling down these huge files made with architecture software like Rabbit or Autocad 3D or many others and what they actually create are scaled down versions of big models and not real scaled mock ups based on what they would like to do. So it’s a bit different creating scaled 3D printed real objects from model like real scaled buildings. So there are a couple tricks we’ve been developing recently so I’d like to show you. It’s very easy and we’ll save a lot of time for you and a lot of trouble for us in printing. I’m showing you how to fix an architecture model, a very simple architecture model this week.

Jessica : Can I ask you one quick question? What was the reasoning for the file being refused? What was the error message that was received?

Alvise : The reason provided by the printing center was “File too fragile”, but this can be sometimes a lie. And the reason I’m going to explain it right now. We have the file here, we’re moving to the review tab to access the fragility check, and in this fragility check we’re showcasing fragile areas in a red color, and as you can see in this model at this scale (190cm long, more or less), we have some red sticks in the middle of the building, and we have a huge red area here, so our technician by watching this fragility check has been recognizing that this bug part was too fragile to be printed. But the real reason for this red color is not fragility but is another one. You can find it out with this cutaway tool, it’s very useful to check what’s happening inside the model, so I’m just sliding this button and I can choose the axis I want to cut away here on the right corner of the screen and move my cutaway position with the slider. I’m going to set it exactly in that red big part we were seeing in the solidity check and watching inside you can see that as I was saying all the parts that composed the model are kept separated in this file and are now intersecting. So when the solidity check tries to understand the thickness of each part it’s actually watching the intersections between each parts, so it’s recognizing those intersections as thin elements that are not. So what we want to do when we have this kind of model is to delete all the internal geometry or all the internal intersections that we don’t see from the outside and it’s creating problems while printing. So this kind of problem is not automatically repaired by the website when you upload the file because not every model require this kind of reparation because most of the time we don’t have this kind of intersections like here. But we do provide additional algorithms that can be used by everyone.

Jessica :Sorry I have a quick question for you! Before we get into the algorithms can I ask you can you zoom on that trouble spot just from the outside just not the cutaway view? Because you can’t even tell that those, like columns, are going down into the rest of the model from the outside. You would need that cutaway view to see what’s happening on the inside, right?

Alvise :Yes, exactly, that’s why we provide it. It’s very good to always check what’s happening inside the model. Even before uploading your file, always be sure that there’s no additional geometry inside, because if you’re doing for example a rendering for a video game or other application for your 3D model, this will not matter at all. But in 3D printing, we’re transforming all this information into real materials, so the machine is going to take in consideration every part of the model, even the internal ones. So that’s why this part has been refused.

Jessica :That’s amazing, thank you so much Alvise.

Alvise :That’s how architectural software works. Every part, every element is considered as a single standalone element, so every column is separated from each other, every floor, the roof, and every element is kept separated in the mesh.
So let’s go to find out where this repairing algorithm is. We have to access the repairing environment. First of all I’m going to “My objects”. It is the library where, in my account, all the models that I uploaded so far during these webinars are, and I’m going to the last one I just uploaded, the architecture model. Clicking on this arrow on the top here, this little window pops out and I move to Design Settings. I access the Design Settings of my 3D model. I have the viewer here again and a lot of other options, but what I want now is this button “Check Repairs”, so everytime you upload a model in Sculpteo, we check if this model is appropriate for 3D printing. If it’s not, we run a quick automatic algorithm, that is the one that’s been running on this model, and we try to repair it and most of the time we’ll do it. And there are specific situations like this one where the user is required to judge by himself whether to apply or not a different algorithm. In this case for example, about the architecture model, I know that there can be the usual problem of intersections, so I’m changing my repairing type. So in this window I see the Automatic algorithm selected, this is the one that’s already been running. I’m opening this new window and I select a new one. There’s a bunch of different options. We’ve already been talking in some previous webinars about another type of reconstruction that was the Visible Reconstruction, that was working for a figurine if I remember correctly. Today we are going to use the normal Reconstruction Algorithm. As you can see it’s also good for architecture models so you can use it. And the algorithm is running, I think it should be fast. Yeah, it’s already done.

Jessica :Wow, it’s already done.

Alvise : Yeah. It’s good to get a check. So for example here I see that the algorithm did some mistakes. I can change some parameters so these tresholds… Well sometimes this happens when the threshold is too low, so I’m just going to move it a bit up to see… 8 percent more… Let’s see if something changes… Yes, so that hole has been closed and now it looks exactly like before externally, but inside it should be different.

Jessica :Sorry, can we check that out? Are we able to do the cutaway view and see that it’s been taken away or?

Alvise :To access the cutaway view again we have to go back to the previous environment because we don’t have cutaway view in this repairing environment.

Jessica : Okay.

Alvise :So, we click on Continue. So we have applied this new repairing type, this new algorithm to the model. Let’s go to the solidity check. So, yeah, the big red area is now green, and we can use the cutaway view and slide it to see that there’s no more stuff inside. So what the algorithm did is cutting the shells that was composing the model at their intersections and then deleting everything that was not visible from the outside, and then stitching those new created shells again. The model has been correctly repaired.

Jessica :That is awesome, what is the name of that algorithm, the one that you recommended for architecture?

Alvise : It’s simply called Reconstruction.

Jessica :Reconstruction, ok, the Reconstruction algorithm, perfect!

Alvise : We’ve been talking about, as I told you already, I think like a month or two, about another type of reconstruction, that was the Visible Reconstruction. What’s different between these two types is that the visible reconstruction is remeshing the model so it’s actually creating a new mesh

Jessica : Ok

Alvise : That way of reconstructing is good for very organic models or figurines like the example that we had because it’s kind of smoothing out every edge. That is what we don’t want in this case, since it’s an architecture model every edge needs to stay sharp so we didn’t remeshed it, we just cut and delete the geometry that we didn’t want.

Jessica : Perfect, that’s awesome!

Alvise : Alright, so we solved the main issue that was all the unwanted geometry inside, but we still see red parts in this solidity check. We now know, because we have been applying this reconstruction already, we now know that these red parts remaining on the model need to be fragile parts for sure. So I have to be 100% sure about that, we can check the thickness of these parts simply by zooming in a bit to find the area we want to analyze. And we just left-click on the red part, and this measuring tool appears, telling us that the thickness in that exact point is just 0.4mm, so too thin for the material we’ve been choosing, white plastic in this case.
So we now have another issue. The issue is fragility in some areas of the model. And we need to bring this measure to at least I would say 1mm. 0.8 is the minimum required for white plastic. You can find all these information on the materials page. We know for experience that is 0.8, so twice of what is now. So let’s quickly show how to solve this problem. I’m not using our automatic thickening tool this week. We’ve been going through that tool in detail last week, and we also underlined that it’s a very good tool once again for organic models because what it does is kind of smoothing out those red areas with the green areas. So doing so, applying this kind of tool in this case, these red areas will kind of be fused, merged with the green areas around it, and this way all those sharp edges will disappear and it’s not what we want. What we want to do is make those parts thicker and reupload them. So I’m going to a test software, I need a specific software to do so. I can’t modify manually geometry in the website, unfortunately. I’m doing that with 3DS Max.

Jessica : Can you repeat that? I apologize, you kind of cut out for a second

Alvise : Yes. Alright, so I was just saying I’m not using the automatic thickening tool to thicken the model, because it’s not appropriate for this kind of application. Our thickening tool will tend to smooth sharp edges, so it’s great for organic figurines or this kind of models like the example last week, which was perfect, it worked great. It’s not good when you want to keep sharpness on edges, and that’s the case of our architecture model.

Jessica : Ok, perfect. So what system are you using for correcting this itchy?

Alvise : It can be done with several softwares, any kind of software that can open a STL file is able to do what I’m going to do now more or less, so you can do it with Blender or whatever, Maya. I’m doing today with 3DS Max 2015, it’s a software by Autodesk.

Jessica : Perfect, awesome!

Alvise : But it’s a simple operation that can be done with the software that you perhaps already have installed on your computer. So I’m going to recall the original file before the one that I uploaded on the website. When I import something in 3DS Max I’m always unchecking these options because it’s making the importing very slow, so I really prefer to uncheck these options. Even the Weld option, even though I’m going to weld the model again in seconds. I’m going to explain you why exactly. So here is the model, so I’m not going to show you how to thicken every part of the model because it’s kind of repetitive. I will just thicken this red area that I’ve been zooming in before in the website, so this kind of external barrier here.
So, I’ve been importing this STL file in 3DS Max, and if I want to select the entire barrier, since it’s a separate element, because it is the way It’s been modeled, I should be able to do it with the Element Selection, but when I use it in this moment you can see that it’s only selecting triangles, that’s not what we want. And the reason is because I didn’t weld the object, so every triangle is considered as a separate element by 3DS Max in this moment. So what I have to do if I try to edit it is right-click first in the model and convert it to an Editable Poly, and then open my Modifier Tab, scroll down to find out the Vertex Weld Modifier, and apply it to the model. This threshold here should be ulled down to the minimum, because all the triangles are already in the perfect position, I don’t need to really weld them together, they just need to be recognized as one single part of the model. So 0.1 as a threshold is enough. And if I now apply another Editable Poly on top of that, and I go back to the Element Selection tool, I’m now able to select these parts singularly and make everything is faster than selecting each triangle individually. So I will select all of them, all these parts at the same time, keeping Ctrl button pressed and then left-click my mouse. I will simply scale these parts in one direction, to make them thicker, so nothing special, an operation that can be done in any software, with SkecthUp, anything that can read the mesh file. So I’ve been selecting all this side, then detaching it with this button here under the Edit Geometry Tab. Detach it from the rest of the model, so I have two objects here on the left of your screen and I’m going to hide the main part of the model to work just on this one. What I want to do is, as I said, scale this part in only on the Y axis in order to make it more or less twice thicker than it is now. So the Select and Uniform Scale to appear to the top, I need to right-click on it so that this window appears and I’m able just to type the transformation on the Y axis from center. So what happened is that my part moved, this means that pivot of the object is not centered, so let’s go back and let’s center the pivot in the middle of the object. This color gizmo here represents the pivot of the object, and it’s outside the object, so if I transform it, the transformation refers to that pivot and moves the object, that’s not what we want. So to reposition this pivot, I’m moving to this Tab, the General Tab. Ah sorry, the Hierarchy Tab, the third one just after the Modify Tab. And I’m going to click on Affect Pivot Only, and then under Alignment here, Center to Object, so the moment I click it, you can see that it’s now in the middle of the object. Go back to the Modifier Tab, and let’s now try to reenter 200%. And now the object has been correctly scaled.

Jessica :Perfect, and it didn’t change.

Alvise : And it didn’t move, it’s still in the same position and it’s twice large in the Y axis only.

Jessica : Awesome.

Alvise : Let’s unhide the rest of the model. So there are now two separate elements and I should do this operation for all the parts that I see red in my solidity check. So when I work in this kind of operation, I always keep my solidity check in Sculpteo’s website open in a screen or in a part of the screen to check which are the fragile parts and then I keep my software in another window to actually do these reparations.

Jessica : Perfect, so this shows than you can kind of bounce between the two and see what you need to repair in your 3DS Max based on what Sculpteo is recommending. It’s really interesting because I heard people say that before that they use our website to kind of check for errors, and that’s basically that system you’re talking about… Emm, and just to let you know we have about 3 minutes left, so if you want to go ahead and share like the most vital important information from this point we can kind of ,may be go a little bit quicker!

Alvise : Yeah we can resume what we’ve been talking about so far. It’s an architecture model and that it’s kind of simple but it’s still presenting the most common issues from architecture models. They are made of several intersecting parts that are kept separated in the model, they represent different shells. So first thing to do when we note this thing, thanks to the cutaway view, is to apply a Reconstruction Algorithm that is been specifically developed by our Developing Team for architecture models. You can do it by your own, it’s very easy and it’s in the Design Setting of your object that you can find in your Object Library. So it’s a bit hidden but once you do it once you can find it very easily every time. After the algorithm has been applied, we notice that the data’s just been repaired. We find out there are still some red parts in the solidity check, they are fragile parts of the model, they are still fragile. So we went back to the modeling software, 3DS Max, even if it might not be the original software where the model has been modeled on. We’ve been just editing the red parts that we saw on the solidity check and that’s it. I’ve been doing it just for a small part, you can repeat that for all the fragile parts that you have, and at this point I can just quickly go back to 3DS Max. You see that I have still 2 parts on the left because I have been separating them before. I have to remerge them in order to export the modeling correctly, so I’m to click on Attach this time, and it will select the second part, and I have one single part again. In this configuration the model can be exported again as an STL file, reuploaded to Sculpteo, and the Reconstruction Algorithm reapplied if necessary, and then 3D printed.

Jessica : Awesome, I was going to ask you about that if it automatically kind of factors in the reconstruction that you did or if you have to do that again. So, thank you so much for going into detail with that Alvise, I totally appreciate it and I’m sure our viewers do as well.

Alvise : Thank you for asking.

Jessica : Yeah absolutely! Once again this has been Ask a 3D Designer, you can catch this every Tuesday at 9 o’clock PT if you’re in the US. So, once again, if you have any questions of if you want to provide any feedback for our new Google Hangout Setup or any additional questions referring to Alvise’s kind of walkthrough. My personal email is jessica.hedstrom@sculpteo.com Perfect, so I think we are going to end that there!