3D printing and stl files?

[Tom]

Hello-

 

I apologize if this has been answered before but I did a search for "3d printing" and ".STL" in the AM forums search and it came up blank...so here goes:

 

When exporting an .STL file with AM17, does the mesh need to be continuous to be recognized by the printer?...or can there be multiple models intersecting each other, without there being one unified mesh? (see picture)...

 

In this simplistic picture there is a sphere (figure A) with some of the points pulled out..and then there is a sphere (figure with a cylinder intersecting.

 

Are both of these models "legal" to the 3D printer? Will both models "print out" accurately?

 

Thanks for any insights...

 

Tom

[Fuchur]

In general it should work but i tend to at least close the cylinder in itself. That works... never tried without till now.

 

See u

*Fuchur*

[John Bigboote]

Tom's picture begs the question – do you need to specify depth when modeling for 3-D printing or would his image print as a solid?

[Tom]

Thanks for the feedback!

 

John also added another good question...

 

Is there a way to define depth in the walls of a model.

 

For example, if there was a standing character, would the printer always print it as a complete solid? Or can you define that the walls of the figure have a certain thickness, and leave a hollow space in the inside?

 

Does anyone know?

 

Thanks again,

 

Tom

[robcat2075]

I think it's been said that the software has some ability to optimize things like hollowness, but someone who has done it will need to chime in.

[pixelplucker]

You can use multiple shapes and butt them to each other and they will print as one piece. not sure how intersecting objects would work.

Objects that are very close will print as one piece even if they are not touching in the z axis depending on the printers resolution (.001 for wax, polyject and sla)

Meshes do need to be closed.

Make sure the normals are facing outward or your file will have errors.

 

You can use a free program like Hexagon to weld close faces as well as check the stl file prior to export.

 

As far as wall thickness you have to set that yourself. It is a good idea to build structures hollow when possible to reduce the cost of the prints since most will charge by cm³

 

I thought there is a way to offset a surface in AM, was it a plugin?

 

In AM you can build the object in separate patches as you need, keep cp's between patches lined up so when you export them you can average weld them into one unified shape.

[Tom]

Thanks for the feedback!

 

With 3D printing coming down in price it is great to have a software program like AM to play with!

 

thanks again,

 

Tom

[Fuchur]

Thanks for the feedback!

 

With 3D printing coming down in price it is great to have a software program like AM to play with!

 

thanks again,

 

Tom

 

You can of course hollow ur objects. My makerbot rep2 has printed many of these hollowed stuff. The only problem may be overhangs which can not be printed without supports if they are overhanging too much. (The layer u r printing just needs something to be printed on).

 

Additionally to that u need to specify an infill level for solid stuff anyway. (By default something between 10-15%.

This means that there will be many holes in an object anyway. But that is nothing u need to worry about too much. The infilllevel maybe increased if u need a moe stable object which needs to be able to handle higher pressures etc.

 

See u

*Fuchur*

[pixelplucker]

Maker Bots software automatically hollows out objects? I did see where you can set a % of fill on objects. That seems pretty handy.

 

Most of the stuff I output goes to polyjet or sla. Unlike fdm systems that draw on tool paths with material, the polyjets go line by line, row by row.

You need to manually create the hollows within the model.

[Fuchur]

Maker Bots software automatically hollows out objects? I did see where you can set a % of fill on objects. That seems pretty handy.

 

Most of the stuff I output goes to polyjet or sla. Unlike fdm systems that draw on tool paths with material, the polyjets go line by line, row by row.

You need to manually create the hollows within the model.

 

No you have to create hollows yourself. There is just an infill-level...

that means that if you have a solid object (or part of it) it will be partly hollowed with a certain infill-level. It will create a pattern inside, quite equal to the once found for instance in bird-bones (which makes them very light but very durable anyway, because the inbetweens do not add to stability but only to weight).

 

See you

*Fuchur*

[pixelplucker]

Ahh interesting, I'm waiting to see the Formlabs sla machine, supposed to be out next month. If the resolution is good for what I need I may spring for one. Tired of using service bureaus that are run by incompetent idiots. The Solidscape machines are still pretty pricey even for the older used ones.

[John Bigboote]

Speaking of waiting... Staples Office Supply stores may be doing 3D printing soon...

 

http://www.gizmag.com/staples-mcor-easy-3d-printing/25284/

[Fuchur]

Ahh interesting, I'm waiting to see the Formlabs sla machine, supposed to be out next month. If the resolution is good for what I need I may spring for one. Tired of using service bureaus that are run by incompetent idiots. The Solidscape machines are still pretty pricey even for the older used ones.

 

You mean if they does not loose the law sues against them....

 

See you

*Fuchur*

[pixelplucker]

They in trouble? Patent violations? Uh Oh.

3d systems seems like a pretty scummy company. I had looked into some of their products. I have some concerns on their overall business ethics especially when they contact the customers of the service bureau's that use their equipment to try to make sales.

 

Not sure what patent they might have violated but sla is pretty old technology, uv curing resins is also old technology. IMO it is probably some bully tactics in order to take the company over.

[robcat2075]

I was sure someone here had said there was software that could take your STL file and optimize it so that the interiors were hollowed and supports were created for overhangs as necessary.

 

did i dream that?

[pixelplucker]

You can use Hexagon. There is an offset surface function built in as well as the ability to view and orient normals, weld points, decimate and close openings. Daz still offers it for free and it is far easier than Blender.

 

I believe that support structures will depend on the type of printer and usally the output service will make those. In the case of polyjet or solidscape printers, the support structure is printed at the same time as the main material (positive and negative models printed at the same time) so there is no additional modeling required.

 

Support structures are needed for FDM such as Makerbots or SLA systems where the resin is too fluid to suspend the objects.

[KingVidiot]

Fix your STLs with Netfabb Cloud Services (free):

http://cloud.netfabb.com

 

I used this while at Siggraph last year before printing something on the Makerbot demo printer. It came out great.

[Fuchur]

Fix your STLs with Netfabb Cloud Services (free):

http://cloud.netfabb.com

 

I used this while at Siggraph last year before printing something on the Makerbot demo printer. It came out great.

 

In my experience you dont have to... It is not a bad idea, but the STLs written with A:M are fine with the Rep2 given that you watch the normals.

 

 

See you

*Fuchur*

[pixelplucker]

What about open surfaces such as lathe objects, don't you need to close those entities first?

[Fuchur]

What about open surfaces such as lathe objects, don't you need to close those entities first?

 

I actually never tried to print an open object, but I am very positiv that you have to do that.

Just close it and you should print without a problem.

 

See you

*Fuchur*

[pixelplucker]

If you want to do a test, make a lathe object.

Scale the ends to close it and test.

 

See if the cp's just have to be close enough to read as closed when printing or if there are any errors.

 

Curious if the software will read in multiple cp's as one if the resolution is finer than can be printed.

 

If that is the case then creating objects in sections will be really helpful.