Proper modeling for 3D Printing question

mdimeo

Hey guys, I have a question about a freelance gig I may be picking up soon. A high profile client may want me to model something SIMILAR to this (this is ripped from my portfolio) with the intention of 3D Printing it. Now they told me they don't know the work flow but will expect me to.

Keep in mind, I'm not actually printing this model, but I was told to expect what I will be hypothetically building to have a similar level and detail, with exposed bolts and everything.



Now I have a couple of questions.

I saw this posted in a different thread. http://www.cadspan.com/info

This company will generate an entirely new mesh by "shrinkwrapping" what you send them. This appears to be the ideal way to go, as expecting me to model something with that much detail as one contiguous mesh is just absurd.

However, the company may decide to go cheap and tell me that I need to provide the mesh myself, and won't pay for CADspan's conversion.

If this is the case, what else are my options?

I would say that modeling something like that as one contiguous mesh is next to impossible. Are there any advanced boolean tools I can use?

How about the new Zbrush exporter? Can I import the high res mesh from max/maya into zbrush, and then export it out?

I'm just trying to plan ahead and prepare for the worst...CADspan is definitely the way to go but I need a plan B.

Thanks guys!

cryrid

Do you know what kind of printer it is? I've dealt with two different ones at work (plaster and plastic) while printing a lot of armored vehicles, and both allowed the mesh to have polygon islands. The only catch was that they had to intersect / be pushed into the other islands a tad bit so that the islands wouldn't be printed as seperate objects.

The work flow we've been sticking to is simply:
1 - make sure there are no open edges
2 - if you're using floating geometry, make sure they collide into the surface
3- delete anything that is just going to get broken off (the antenna and wires on yours for example)
4 - Re-enforce anything that looks like it might get broken off but is critical to the object (we'd often just float some extra cubes or cylinders to give things more of a connection into the main body)
5 - Try to hollow it out as much as you can while keeping it strong if its bring printed with the plaster/powder printer (the material is more expensive). Plastic prints are cheaper and have different automatic options for how much material is used inside the print, but plaster prints are solid.

ericdigital

My day job is modeling armor for 3d printing as well, and it definitely matters on the machine. If the 3d print is going to be made into a mold there is things you need to think about, like exaggerating the size of bolts and things like that so they print with enough detail. Depending on the build platform of the machine you may have to break it in half. We work with a pro-jet machine that has a 7inch max build platform, so if anything is over 7 inches you have to cut it. It would be ridiculous if you have to model something as all one mesh, with us we shove things through each other and the whole nine, prints fine. Though that could depend on the machine. Just like cryrid said, just important to make sure things are fully intersecting.

Cost things, like hollowing out areas may also be important to the client. Since the less material used = better

really just everything cryid said, he hit some great points!

mdimeo

excellent advice guys, thanks a bunch. I'm sure when the client figures out if this will actually get printed, they'll have more info about the printer itself (I currently have none) and I'm sure I can ask someone that works at the company how to best approach it.

thanks!

arrangemonk

in former times people printed their models out to paper and then filled the papermodels with pu-foam

teh cabels on the side wouldnd seem critical to me, if they would be intersecting with the tank itself

Microneezia

Im also interested in 3D printing. Is it common to require a continuous mesh? Ive never had this problem when using a C&C machine - but that was for cutting foam. Couldnt you take all the seperate pieces though and project them in Zbrush to make a single continuous mesh? I dont think the huge polycount will matter.

cryrid

Im also interested in 3D printing. Is it common to require a continuous mesh?

I'm not sure how common it would be, but we've used a ZPritner 450 and currently a Dimension 1200es, and both allow for non-continuous meshes. You just have to keep in mind that if it isn't connecting in the 3d mesh, it's not going to be connected when it prints. In some cases you actually need to make the model non-continuous if you want the printed model to have moving parts; printers like these can be accurate enough that you can make rotating turrets, gear cogs, and even wrenches that open and close.

CheeseOnToast

Which software do you use cryrid? To speak to the printer I mean? Magics RP or similar? I've been asked for a continuous mesh for an Objet printer, and it's a major pain in the arse.

Couldnt you take all the seperate pieces though and project them in Zbrush to make a single continuous mesh? I dont think the huge polycount will matter.

You can, but expect to be doing a whole lot of tedious cleanup.

DarthNater

I did some 3d printing (sorta) a little bit ago. I made some molds for pouring soft plastic fishing lures. It was a very basic design (nothing like your vehicle), but let me share this with you:

STL Check is you're friend (in Max anyway haha), you can also use Mesh lab, it has tool to check your mesh for printing...

cryrid

Which software do you use cryrid? To speak to the printer I mean

CatalystEx for the plastic / Dimension, Z Print for the older plaster one.

ericdigital

For us, any parts that are going to be moving, like hatches or the copula we print separate so they can be assembled after. Anything that sticks out kind of far, antennas, tall lighs etc we make a little hole on the main body then give the piece a peg and glue it in after, to prevent it from breaking. With most machines, making sure you have a proper amount of polygon's is really important since you could end up seeing faceting. Or if you have a plane that isn't perfectly flat when it gets triangulated you'll end up with a big nasty facet down the middle and that's always a bummer.

We generate all our .STL files using Deep Exploration then check to make sure everything is air tight in magics, though that not the cheapest software to have access to.

Cadspan

mdimeo, a few comments on here, while hopefully avoiding any spam. I am new on here but I assume it is frowned upon.

There are stl editors that do a pretty darn good job of "booleaning" incredibly detailed meshes together, but they are tremendously expensive. For your workflow it would be better to use a service bureau with a lot of experience in that sort of thing and just pay the hourly rate. As noted above, magics and deep exploration are a powerful combo, but you would need to do a lot of 3d printing to warrant their purchase.

or

You can use cadspan. There is a free trial that you can use to find the appropriate settings for the tank you have pictured, which will give you the knowledge needed to use cadspan for your production part. There are single use and monthly pricing options that will likely come out to less than 1% of the 3d production budget so it should not be a problem to price the usage in to the model.

or/and

You should determine the material/resolution needed for your final 3d print and find a service bureau that will print the final part. have a conversation with them about what their requirements are for a print. Some printers will allow multiple shells, allowing you to create everything as separate components and the parts will simply fuse in the printer. Some printers will not allow this.

Note: there are other considerations that need to be factored in. Interior volumes need to be solid, normals must all point outward, no holes or gaps (the part(s) must be water tight), and many printers will not allow coincident or intersecting triangles. The cadspan team is currently writing code to automatically address all of these issues to make 3d printing accessible to all markets.
A great number of these issues can be checked bu uploading your data to a service provider like shapeways. They have an automated system that helps check files. I have only used it once, but it seems like a pretty easy verification system and also has automated pricing.

I hope this helps. If not, let me know where I can clarify details for you and I will.