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olivierc

What's your favorite calibration print?

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Hello, my name is Olivier. I just order an Ultimaker kit this weekend, now I just have to wait. In the meantime, I'm gathering as much documentation and info as possible. I already have a list of upgrades to print, I'm learing about Cura, Marlin, temperatures, infills, stepping... as much as I can, even if for now it's just theory.

I'm a 3d modeller, that's my job, I work in cinema animation for a living, my objective it to print my own characters and I know it's going to be a long way before I can achieve that. I know it will take a lot of tuning.

That's why I'm asking, what is the object you generally print when you want to test your setting? There are many "calibration" things on thingiverse, but that's the problem, there are too many, and most of the time they are very specific, to test one thing only(retraction, overhang, levels...) I know those test objects are not as representative as a real "production" print, but I guess you guys don't print a 20cm tall yoda for every temperature tweak.

So I was wondering, what is the small object you print when you want to check if everything is ok before starting a 10 hours print?

Sorry if I'm not asking this is the right section or if it has already been answered ten times.

thank you, Olivier

 

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I actually like using Yoda at half scale and hollow with several perimeters to check filament settings as it gives a variety of quick movements, single walls in the ears, overhangs, and there are distinct features to be recognized. Plus, the print ends up as a product, not just a widget (Kids love it if you toss them a Yoda figurine and say Merry Christmas).

 

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All of them :-) I just print random stuff to test my printer, settings, and software tweaks (then again, I develop the software, so doing lots of different things is important for me)

Actually, as a 3D modeler, what would be important to learn is that "manifold meshes" are important, as well as "no intersecting faces".

As for the kit, the first 80-90% of the print quality comes from properly tweaking the mechanics and proper filament, the last 20-30% comes from tweaking the settings. (On some complex this can be different, but for most prints this is the case)

First thing you will most likely need to adjust is the short-belt tension. It usually goes wrong there for kit builds quality wise. As the printer works fine with lose belts, but won't achieve super quality.

 

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Thanks for the tips Daid, and thank you for your hard work on Cura. Manifold faces is not a problem for me, since I model for animation, my meshes are sooper clean, all quads and all. I'm more confused about the "no intersecting faces". Does that mean within the same mesh (i.e, folds), or does that mean you can't have separate meshes intersecting each other? I'm asking because, for instance, on this lower res version of yoda http://www.thingiverse.com/thing:10752 , you can tell the eye are separated meshes interesecting with the head (unless they have been "booleaned" together). Is that an issue? because most of my models are made this way. Does that mean I must merge eveything first? (hug, I hate booleans!)

 

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Ok, I gess it's not much of a problem, I can just subdivide the model a couple of times before merging (booleans work better with more faces) and then decimate it in meshlab (does a better job than maya).

But it's weird, when I load the stl of yoda in cura (failed to load it in maya, while I can export to stl), I can clearly see the two spheres inside the head, they have not been merged into a single mesh. If they had been merged with a boolean operation, I should not be able to see the spheres but just a single volume. So, unless I'm missing something, how come people can slice it with no problem.

 

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The spheres in the yoda eyes are causing problems, as they are printed hollow instead of properly filled. It's one of those models where it doesn't work as designed, but works good enough to get the proper results.

What happens, on a "basic" level, is that the code is doing kind of a "exclusive" boolean operation, where 2 pieces overlap, instead of filling it, it makes that part empty. (it has good reasons to do so, but it can give unexpected results)

But you can also have "self intersecting meshes" which is simply the same problem, but less easy to solve as you cannot boolean it together in most 3D modeling software. A simple example would be an arm, which is usually modeled straight and then animated with bones into the proper standing. With this animation you get internal triangles, usually at the inside of the elbow, that intersect with it's own mesh.

With this problem it's always "sometimes it works, sometimes it doesn't", but it's best to understand where the problems come from so when it doesn't work you can fix it.

(I like printing stuff extracted from 3D games, which do just about anything as long as it looks ok, so those meshes usually require cleanup for proper printing)

 

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ok, thank you for clearing that up. I will be very careful when preparing the models. while I'm planning to use cura and kisslicer, I have read that netfabb can fix this kind of things automatically (merginf interesecting mesh together)

Edit: btw, if a someone wants to move this thread to the Q&A section, since it's more about answering a n00b's questions than the art of printing :)

 

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Yeah, boolean'ing individual parts together is not a problem. As long as the object are closed (which is a requirement for printing anyway) maya or 3dsmax do that very well.

The harder part is like what Daid described, when a same object intersect itself. I'm particullarly thinking of hands, when you pose them in a tight fist, all the fingers intersect each other and with the rest of the hand. As far as I know, there is no way to self-merge mesh in maya or such. One way I see to solve it is to detach those fingers, cap holes, and boolean everything together (and eventually remove inner shells inside the first that might result from boolean) It sounds doable, but when you have plenty of those contact zones on a character ( elbow joins, arm pits, boobies...) it might become a nightmare even with a script to speed that up.

Edit: ok here is an example, if I want to print this guy : http://features.cgsociety.org/newgallerycrits/g98/219898/219898_1262725007_large.jpg

I already know some parts won't work, like the barbwire around the axe or the thin grid on the "mouth". The blue body part is modeled in one piece. So I guess I can boolean the belt and suspenders in, same with gloves and boots (I would print the grenades and axe separately and glue them later)

But the problem is his left arm (arm side on picture :) ), it's inter-penetrating the body, it actually looks better and more natural like this than if I had kept some space between the two. Is that an issue? and how would one solve that? Oh and same thing for the hand, just like I described above, the three lower fingers are touching each other

 

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If you have the model, just try running it through the cloud service for that. I suppose what I'm suggesting is that you limit the number of things that you make the cloud service do, as the more you ask of it, the more potential there is for an incorrect interpretation of what should be taking precedence.

 

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