Tom and Tracy Hazzard’s first international question is from Eduardo Martini in Brazil who asks about some tips for successful 3D print designing with Rhino. Although this is a little technically specific to Rhino, some of the tips are good for other 3D modeling programs as well. They share some key tips for using Rhino and what makes it a little different from other programs. Tom also uploads a video tutorial to show you the exact steps he goes through to make a better 3D printable model.
Listen to the podcast here:
Tips For 3D Print Designing In Rhino
We’ve gotten our first Ask Us Anything question from the country of Brazil.
I’m excited. We’re international. We have fans.
It’s great to know that our podcast is reaching far and wide across the world.
It’s rewarding because he mentions that he listened to all of them. I’d be so excited about that. I feel we pour a lot into them. It’s nice to have somebody listening.
It’s nice that some people are appreciating it.
In this case we have an actual voicemail message. We got a lot of email questions and other things like this, but this is a voicemail question and so I thought we’d play it.
It’s from Eduardo Martini in Brazil. Let’s go to the question.
“This is Eduardo Martini. I’m from Brazil. I have discovered your podcast. I have listened in all your episode and it’s good, nice tips and tricks. I have a question about designing a product or using Rhino. Maybe you can put some tips and tricks, easy ways to process it in Rhino. What are the steps you usually do from start to finish? It would be nice to see. Thank you.”
To go over how we designed something from start to finish would take hours and hours.
The thing is that it’s no secret we use Rhino. We’re a big proponent of it because we use it for some specific reasons for what we design, but not everybody does. Some of these tips that we’ll go over are universal. The settings might be different in your software. He asked about our process. We should start at the very beginning of our process and at least make a mention to the fact that we don’t start straight in Rhino all the time. We do research. We studied the market. We decide what kind of products. We go out there and we look at things. We create a concept and usually we sketch it because we design that part together. It’s a little easier to sketch than it is to be individual on the computer. It’s hard to team design on a computer.
For us the most important thing is mind share. We have to communicate with each other. We sketch initially. We usually have some idea of what we want to create by the time we go to the computer. While we do design in the computer as well, things change and evolve there. It’s important that you do have a concept first.
That’s where and how we start. We start by sketching.
I’m going to go over a couple of key tips for using Rhino and what makes Rhino a little different from other programs. Hopefully, that will answer the question as best we can.
We’re going to need to throw up a video at some point, maybe some tutorials for some specific things. It will be on our website because there’s so much more detailed information. Other videos and tutorials we can refer you to if you want to learn how to do something specific in Rhino.
The first thing when you are creating your Rhino file that you’re going to build your geometry in, you have to decide what the units are that you’re going to build it. Are you going to build in English units or metric units? This is my first tip and recommendation is that most 3D printers are all communicating and building the language of millimeters. You hear the term microns or 200-micron or 100-micron layer thickness. That’s all based on millimeters. A 100 microns is a 10th of a millimeter. You can start with the small objects millimeters as their template file. I recommend adopting the metric system, especially as you get into 3D printing.
We have an idea of what we want to make when we go to the computer and a sketch or other things. The reason we like Rhino is we’re designers. We went to art school. Rhino is primarily a surface modeling program. A lot of other programs only use three-dimensional primitives like a cube, a sphere or a cone. You add or subtract from them. You can do that in Rhino, but Rhino allows you to build things with surfaces. We generally are creating curves, two-dimensional curves of various shapes. An important thing to understand with Rhino is when you’re making three-dimensional objects, you can build parts with open curves or closed curves. Keep in mind that when you’re going to go 3D print something, your solid model needs to be a closed object. That’s key going forward.
This is different from other types of manufacturing techniques where you’re able to use those open curves or creating or rendering or something.
When you’re creating or rendering your animation or anything on the game industry, everything can be wide open. You just care about how it looks. Here you’ve got to care about the object you’re making in an STL file that’s got to be printed.
They call that water tight.
You have to end up with a watertight model.
It’s a closed, watertight and nothing is leaking.
We start with curves. We generally can extrude them or loft them. There are many different ways you can take a two-dimensional curve and make it into a three-dimensional object.
There are a lot of tutorials about how to do all of those things.
We’ll go through some of those in the video tutorial at some point ourselves because it’s important to see the many ways to do it. That’s what I love about Rhino. I have the most flexibility in creating things that I see in my mind. I’m limited less when I manipulate curved surfaces than when I do solid primitives. I mentioned solid models and primitives. In Rhinoceros, a solid model like of a cube or anything is called a polysurface. They consider it made up of surfaces even if it’s solid. That’s something you have to use too as the name polysurfaces. You make them into solid objects. You make what looks like a 3D solid object, but is it closed?
Solid polysurfaces around can be either open or closed. You need them to be closed. There’s a place in Rhino where you can go and look at the object properties of any little 3D or 2D or line object within your 3D space. You can look at the object properties and the details of it. It will tell you exactly what it is. Get familiar with that if you don’t already know it because you will need to know what state that object is in order to use it going forward and know how you’re going to use it.
An important point to make is that if you do these steps all along the way, it makes it better, less repairs to your file, less messed up geometry that won’t 3D print properly. While you can repair your files later, if you build solid geometry from the beginning, every time you want to make a modification or an iteration, you’re starting out with a solid framework.
In those details, in the object properties and in another place where you can check the quality of your mesh file, which is what an STL becomes. It will tell you if you have a valid geometry or an invalid geometry and why. If you end up with an invalid geometry, it’s probably because something along the way wasn’t closed, smooth and the geometry had less integrity.
If you take a couple of seconds along the way at every stage and just check it, it saves a lot of time and energy later repairing.
We talked about curves that can become three-dimensional objects. The way we do things, we build things more organically out of many different parts and combine them. You use Boolean operations to do that, usually a Boolean union to combine things where you can subtract things with a Boolean difference operation that they call in Rhino and that’s fine.
Would you consider that similar to in a 2D world where you have layers and you’re combining your layers?
That’s a good way to think about it. In fact, in Rhino, you can have even layers of three-dimensional objects to help organize them and keep track of them, especially if you have a lot of different pieces and parts. Conceptually, you’re absolutely right.
You’ve got to combine them because you’re going to print one part.
Even if you’re maybe doing a two or three-color part and you’re going to have multiple pieces, you’ve got to take tens or hundreds of pieces and combine them into 1, 2 or 3 final pieces. You’re combining them and as you combine them, you want to keep tracking those object property details. That will tell you if you have a valid polysurface or an invalid polysurface. If you have an invalid one, you want to analyze that. There are a lot of analytical tools in Rhino to help you see if you have some open seams or holes and fixing them along the way is recommended. Let’s say you’ve got your three-dimensional object built in Rhinoceros and you’re ready to export that for 3D printing. There are better ways to do that than others and those are some of the tips we want to give you.
Here’s the next key thing, and this has a direct effect on your STL file quality. You can set the absolute overall tolerance of your entire 3D world you’re building things in and that’s in Rhino in the units. You can get to that where you adjust units. There’s a setting called absolute tolerance. I typically set mine to 0.05 millimeters. That is equivalent to about 50 microns. I have a 3D printer that can do 50 microns. The default is even finer than that. Why do I not do that? Because my 3D printer can’t achieve that kind of fine tolerance anyway.
You want to see the visual of what you’re looking at in the computer to be equivalent to what you’re going to be printing.
Not only that, if you’re building a three-dimensional model with a finer tolerance than your printer can print, you’re wasting overhead and file space of that 3D file. You’re making it more complicated, more information than it needs.
What if somebody is selling up a file on a 3D download site like Pinshape or one of those sites? They don’t know who’s going to print it. What would you recommend then?
I think 50 microns is still fine. Maybe one micron if you want to go 0.01 on that absolute tolerance. That would probably be the finest that I would ever think you’d have to do. I don’t know how many printers are printing at layer thicknesses of 1 micron. Probably some at Shapeways or i.materialise are able to do that, but not much finer than that for sure. The default tolerance is 0.0001. You see that’s so fine. It’s ridiculous. It makes good rendering, but you can never print anything that fine. This tolerance is important. I would say set it to the minimum dimension of the layer thickness of the printer you’re going to print on. That’s the recommendation there. When you have your 3D object and you want to export it as an STL, there are a couple of different ways in Rhino to do it.
I’m going to tell you the way I recommend it and what I found to work best. You can take any 3D object in Rhino and say export selected, choose STL as a file type and do it. When you do that, you have less control over the quality of that file. I recommend first you select the object and use the mesh command. Mesh command gives you all of the settings possible because all STL files are not created equally. Different programs save different resolutions of files. Here in Rhino, you can adjust it to have many more polygons and vertices, which is finer or purer.
We need a tutorial on this one. This would be a great little one for you to do a little screenshot.
We’ll do a little video tutorial of this because it’s important. Here’s the thing, though. In that mesh settings, there are all sorts of different settings you can play with that are going to affect the quality of that file. I can simplify it for you because you’ve set the absolute tolerance of the whole file already to match what the finest your 3D printer can do. There are only two things you need to worry about. There is a setting called minimum distance edge to surface. You want to put in the same value as the overall tolerance of your file. Match that number. That’s pretty easy. The last thing is minimum initial grid quads. I usually put somewhere between 500 to 1,000 in that minimum initial grid quads. What that does is takes your entire object and divides it over a grid of that many. If I say 500 grid quads and I have something that’s two inches tall cube, it’s going to divide it by 500 grids in each of those dimensions and then break it up into those triangles. That is how you can change the fineness of your file.
It’s very much like a resolution setting and once you choose it, you can hit the preview button and it will tell you in the command line of the program how big that resulting STL file is going to be. That gives you an idea of, “It’s only made of one-megabyte file. Maybe that’s a little too low resolution. Let me increase the grid quads. I’m making a five-megabyte file.” If it’s a pretty simple jump with a lot of flat surfaces. That’s probably okay for me. If you got an organic object with a lot of curved surfaces, you want to increase that amount of grid quads and the resolution of that file.
For example, the tie which we show all the time on our website and on videos and stuff. How big was that STL file?
It’s probably 40 megabytes at least.
It can be extremely complex. That’s a nineteen-hour print for an example of complexity.
It fills almost the entire build volume of the MakerBot printer that we printed on.
That’s where you see that the size of it is also in comparison to the actual complexity and resolution of what you want to print.
You’re going to do some trial and error on this one. You’ll also see that when you do the preview, it shows you the mesh. If you have a curved surface, you want that mesh to be dense and you want the appearance of that mesh to be more blackened on the screen. We’ll show this in a tutorial. After you create that mesh, there is a function in Rhino where you can check that mesh. This is important to do. It will tell you simply, is it a good mesh or is it a bad mesh? If it’s good, don’t worry about it. You can export that file to an STL and print it. If it’s a bad mesh, here’s where you have some choices. You’ve either got to go back in the process, look at your geometry and try to fix some of what’s wrong with it and go through the process again to this point or you can export as an STL still. It will let you export a bad STL if you want to and go to a program like Netfabb or some other program that’s going to repair the problems with that mesh. You have some choices. These are all important. There are some things that you’re going to have to experiment with and find out what works best for you.
It depends on what you’re making. What about some of those plug-ins like Rhino emboss and Rhino gold that we’ve tried over times, are they worthwhile for people?
That’s one of the things I love about Rhinoceros in general is that if you have a particular specialty or field that you work in, there’s probably a Rhino plug-in that addresses some of your specific needs. If you’re in the jewelry industry, they’ve got a plug-in for that. If you are in aerospace, they’ve got a plug-in for that. They have a plug-in that will make it parametric, just like SolidWorks if you want. Rhino is a versatile program because of that. It has a lot of power. That’s why we recommend it and I’m sure you’ll find something useful to you.
People get attached to the CAD program because you spend so much time invested in learning the program itself. It’s hard to switch. You have a productivity drop.
Even though the principles are the same, it definitely will slow you down tremendously to switch from one to another. I could use another program, but I’d be a whole lot less productive if I switched tomorrow.
For us, Rhino has been worth the investment in time and energy to learn because we’ve been able to use it for many different product types. From extremely large furniture pieces to morphic beanbags. We do like all sorts of crazy upholstery and hard products. We do the fine detail with our 3D printing. It’s been expansive for us and that’s good that we already have the skillset.
It’s got a lot of capabilities and it probably will meet your needs regardless of what your industry is. There are other very good programs out there and we’re not disrespecting them.
We are teaching our young daughter Tinkercad. It’s fine to go for those. It depends on where you’re going and what you’re making.
What level you’re at and what works for you. It’s a very hard question to answer. I thank you very much, Eduardo, for sending the question our way. We’re very happy to hear from you.
Tom is always happy to talk about technical stuff too.
This is more technical than our typical episode and thanks for bearing with us, those of you that this is not your cup of tea. In any case, hopefully it helps you, Eduardo. You can always follow-up with a more detailed question in a later date.
To view our possible videos, tips and all those things, you can go to HazzDesign.com. Go to the blog section and it will be right in there. If you have questions or further detailed questions, the more specific, the better. You can do it via the send voicemail link that’s up the top of the page on pretty much every page of our website and also on any social media @HazzDesign.
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