Sorry for my english, is not my native language.
So, I been printing since the last year, only tiny models, and today is my first day printing a large model.
Is a skull of a hospital patient, I’m a bit nervous about the performace of form 2 in this field. The STL file has a lot of acute edges and a lot of bone resorption, and i think is a really difficult printing. I need help selecting the correct angle. Thank you!
I’m afraid you’ll get quite a vast amount of supports no matter how you orient it, and most of them hard to remove
Are you creating the .stl in Osirix or? Is the scan a conventional CT or a lower dose CBVT? Since CBVT has difficulty distinguishing between actively (but incompletely) ossifying structures and actual gaps, are you compensating for that, or is that requested? Is this preparation for planning a surgery or diagnosis? If you can try to separate out large sections with anatomical boundaries that you could recognize when reassembling, you can be more-specific with your supports. Another thing you can do is to create assembly jigs (either outer or inner, using boolean) before sectioning, and these will help you align the sections after printing. Using the clear resin, you can get away with fewer and bigger sections with fewer supports.
It is for planning a surgery. Is a conventional CT. Firts i create a 3D mask from Slicer, and segment the bone structure, making sure that the “craneolacuneas” (the gaps in the posterior region of the skull) were the actual size. Then i export de STL file.
It’s a really graet idea to separate large section, i think if a crop the skull in the midline and print separeted and then make the asambley it could work, what do you think?.
I just finish to make the supports on the skull, what do you think?
I just finish
Very good processing. I think it works best to create the boolean ‘jigs’ to span across where you will segment, then carefully segment where areas are thicker or more distinct boundaries, print, then re-assemble using the alignment jigs…
I second this-
I, too, would break it up along areas of the the thickest and most contiguous possible skull- and model stand off structures linked to each separate section that would offer larger keyed mating surfaces that you could use to stabilize the sections for reassembly, then cut off the stand off jigging.
That is, each section of skull would have a “tree” attached- that mated along a wider area to the Tree attached to the adjacent sections of skull. a surface wide enough that you could literally clamp them together by, or slide pins thru for registration, without affecting the model itself,
In this way you could separate it into shallow concave sections, that you could orient for the minimal necessary support, and gain access to cleaning off the interior supports.
I am posting just to provide an alternate description of the same idea Darick proposed…
Thank you for your answer! The two descriptions of the process are really helpful.
I think I need to do more reserch before printing this patient. I don’t know what a boolean is… :(. But I do know how to segment the skull.
I’ve been told that there is a way to attach de parts of the printing with some kind of resin, like a glue.
But I will try to do de “JIG”, maybe it’s easier than it sound.
If someone of you have an example of the process it would be very helpful! Thanks You!!.
what software are you using to model in?
What we are describing would be easier with some than with others,
So— say you had a thin shelled sphere… like so
i divided this one into 3 parts.
then I built three separate standoff support jigs- each has a plane with registration keys that mates to the jigs on the adjacent two parts. I merge each jig with its section of model.
I can then separate the model parts and orient them to print with the least number of supports- and Rely on the jigs to hold the parts in registration for gluing them together.
after which the jig can be cut off from the model,
The jigs can be less regular than I show them… and they can be as complex as needed to support the lace like structure of your model… they will add stiffness for you to remove the printing supports- and you design the jig to be accessible for removal after assembly.
you can use clamps or clothes pins to hold the jigs together for assembly so that you are not placing deforming stress on the model itself.
Also- while I cut the model and the jig such that their separation planes matched- I did this because it was fast and easy for demonstration… the model itself can have a more complicated separation as determined by where the model is substantial enough to cut… just avoid cutting a jigsaw puzzle- like locking shape…
Oh! what a great idea! I totally think it would work! I been using blender, but i don’t know if you could do this kind of structures. My knowledge about 3D modeling is limited, so i think i need to practice a lot to make this kind ofJIGS!. If you could recomend me a software i will be very greatful! I will try in blender what you show me!
i use multiple modeling apps… but my primary for anything going to print or mill is FreeForm. Its rather costly… but they do make a less costly version called Sculpt.
But having relied on it for 15 years… its still the best app out there for this kind of work.