Hi all,
I’m trying to export a Rhino model for to .STL for a 3d print, I understand there are certain things I need to make sure of like everything needs a thickness etc. Any advice on what I should do to get an error free model to the 3d printers?.. any website links would also be helpful.
Thank you
Martin
Hi,
You might have a look at the Rhino tutorials page, specifically the section on 3D printing…
–Mitch
Thanks, I’ve been looking at that link and others, just wondered if there were so tips from others not perhaps covered. I haven’t found too much yet about the scaling down of the model and then adding thickness. For example I have a model I will need at 1:100 and 1:500, I’ve been told by the printers it’s best to scale it down to the physical size in Rhino and then add 1-2mm thickness, some workflow tips/videos on that process would be useful.
If you have a “solid” model and are planning to print it hollow/wall thicknessed, there will be some work involved. Generally this is called “shelling”. Before going through the procedure, check how much material/time/cost will be saved by hollowing out the model. For smallish parts, it might be minimal, and thus your time invested in doing so will be wasted.
If you decide it’s worth it to shell:
If you are scaling down from full size, do that first, in general the tolerances are in your favor when you scale down, so it it was all joined up before the scale it should be well within tolerance after. Once you have scaled, you will need to inspect all details to make sure that they are not too small for the printer to print - if so you will have to thicken or remove them. You can also do this before scaling as long as you take into account the fact that it will be scaled afterwards. Remember that at 1:100 or smaller, what you are creating is essentially an abstraction of the original, and that you generally neither want nor need the level of detail you have at 1:1 (the machine can’t reproduce it, and you mat not be able to see it anyway).
If the part is not too complex, you may want to try the Shell command and see if/how it works. It might work well, fail miserably or something in between. If it doesn’t fail disastrously, but leaves you with some small open/problem areas to fix, that still might be the best route - do that and then fix the problems “manually”.
If you are unable to shell the object successfully in NURBS, you might try meshing the model and then doing an offset mesh. For this remove at least one surface (or cut a hole somewhere so that the model has an open spot), them mesh the model with appropriate settings. Then try OffsetMesh, solid option, with your wall thickness. Check the model carefully afterwards. If the offset mesh has some problems, you may be able to repair them with Rhino’s mesh tools, but they are much more limited than Rhinos NURBS (surface) tools.
One quick way to check if the model has a minimum wall thickness everywhere is to use the Contour command to cut a series of slices through the model and then examine the slices to see if there are thin spots. You might want to do this in a couple of different directions. It helps if the slices are grouped by slice plane (command line option.)
That’s about as much advice as I can give for a general procedure.
–Mitch
Thanks for the advice Mitch, very useful, I’m a bit embarrassed by what I first sent them now! I guess they are used to receiving crappy data from new clients though 
Sure, it’s a learning process… Anyone who is in the fabrication industry is used to receiving client data of all different qualities… Up to the fabricator to decide how they want to deal with it, ranging from outright refusal to grumbling acceptance to benign help… If you find a fabricator you like (and who likes you), try to develop a working relationship with them and find out what’s important for them, what you can improve for the next time, etc…
–Mitch