Goldberg Polyhedron

Hi all,

Just got my form 1+ up and running, and am looking to print some awesome objects. One of the examples that has been shown on the website is the Goldberg Polyhedron.

I got the .STL from George Hart’s website, and dropped it into preform and scaled it down to 0.7. However, when I generate supports, they go all the way through the model, into the inside where it would be impossible to remove. And this occurs even after unchecking the interior supports box.

I apologize for the noob question, I’m reading everything I can to become better at making models for this machine and printing them. Any advice you have for trying to print the Goldberg Polyhedron or generating supports in general would be great!

Thank you,

I too have seen the new supports go straight through my objects. I did have interiior supports turned on, but in my case it was the trunk of the support penetrating the model, not just having supports inside a closed form. I repositioned the part slightly, and it jiggled the handle enough to stop doing it, but it was very weird.

The Goldberg Polyhedra is characterized by shallowly sloping geometry - because of the lack of sharp points or overhangs it’s a pretty good bed that you can print it without internal supports ( disable internal supports by unchecking the relevant box in the generate supports dialog). You might have one or two that poke up through the mesh, but they should detach relatively easily. Good luck with the print!

Um, he said he already tried that right in his post… It’s just a bug that needs to get sorted out. I know it is, because I’ve hit it too.

We’ve printed a bunch of Hart parts — they can be tricky. One thing to note (shading aside) — is that the spheres are robust and basically self-supporting, so only need supports on the bottom. When I’ve printed them, I’ve just done manual supports — or done auto-generated and then removed all of the supports that cut through.

I’ll pass this on as a support corner case, but I am worried it might be hard for the algorithm to determine whether a body is ‘closed’ or not, especially when it’s full of holes! I’m no expert though.

From an outsider’s point of view - it is VERY hard.
Essentially, such a part doesn’t actually have any ‘closed’ portions or anything even resembling a ‘closed’ portion.

What might help, though, is adding a new option in addition to “Internal supports” that toggles on/off supports that stem from the object itself. In other words, if it’s on, support generation behaves as it does now, but if it’s off, Preform only makes supports that “grow” from the base, never from the object itself.

Edit: Obviously, that wouldn’t completely fix the problem, as there would still be supports growing from the base and through the object, but: a) those can be minimized by adjusting the density; and b) they can be snipped off at the base and manouvered out of the object. Like i’ve said - it might help :slight_smile:

Here is my print of the goldberg sphere oh and a knife I did as well. haha