STL Resolution

[Captain Starfish]

Printing some tubular stuff earlier today I was cursing the RMax for its crappy resolution.

Ooops. This may have been premature. Because I noticed in Repetier Host that the "circle is really a bunch of straight lines" resolution issue exists in the renderings there, too.

Crap. Back to AutoCAD, no, nothing there, then I discover the FACETRES setting. Wind that up to 10 and it's better but still there. Curves ain't curves.

A little more research shows that it may well come down to the intermediate STL format - surfaces described by triangles are always going to have straight lines unless we get stupidly small triangles.

Fair enough, so anyone got any suggestions on the best way of getting a DXF/DWG file into GCode for printing without going via STL, or doing it in such a way that the triangle resolution is nice and fine and my curves look like a nice Maya render instead of something sprited out of a Commodore 64?

[Flateric]

I'm a fellow MAYA user.

There are a number of factor that affect the result of the printed part.

Could you post up a pic of the part and curves that are sub-par so I can get a better idea and offer some suggestions to you?

[Captain Starfish]

Sorry, wrong impression - I am a MAYAdmirer, not a user.

Modelling so far in Autocad and, if I want something a little more organic, it will be Sculptris or blender3d.

Uploading the DWG

pooladapter.dwg

(40.03 KiB) Downloaded 308 times

and finest STL

pooladapter2.stl

(108.19 KiB) Downloaded 265 times

I can squeak out of AutoCAD's EXPORT function with FACETRES=10 (maximum)

Thanks for your time!

[neurascenic]

I think what would be needed is the ability to slice a control object up, and give the result of more control objects.
Problem with .stl, is it is just point to point vector data, no control data... no arcs, no circles, etc...

What your chasing, I think, is more how a CNC Mill would take data.

Are there any slicers (3D Printer) that will accept the Control Data and output gCode? G02 and G03?
Too, does the firmware accept these gCodes? or are they only doing linear codes so far?

Curious...

[geneb]

Captain Starfish, you might want to give DesignSpark Mechanical a try. It's a free design tool that spits out STL files.

g.

[Batteau62]

The following will not help you, it's a total rant on my part-Sorry

I think your(our) solution lies in the AMF file format. Unfortunately it has not been adopted yet. There is hope. Problem is most big players haven't gotten on board.
This is a quote from an article in Develop3d-
http://www.develop3d.com/features/alpha ... rot-to-stl

"Curved surfaces: This is a big one. Rather than rely on planar triangular facets, the AMF format gives a method to create ‘curved triangles’. While the mathematics is beyond my meagre understanding, the AMF format holds curvature values for each edge of a facet."

I started a thread on this subject/file format here-
http://forum.seemecnc.com/viewtopic.php ... 170#p27170

It's an interesting subject. There is a link to an article in my thread about- http://www.cimatron.com/ a major player in CAD/CAM. They do support the format. What's needed is for others to follow them. Very frustrating that the "David vs. Goliath" theme applies here

[Captain Starfish]

Thanks guys. Will give DSM a try, Gene, if there's a Mac version available but suspect it will lead me to the chunky clunkiness of STL once again.

[geneb]

If you're a Mac user, your parametric design tool choices are gonna suck really hard.

g.

[dpmacri]

If you're a Mac user, your parametric design tool choices are gonna suck really hard.

g.

Yup I think you have a choice: Pay big bucks or use FreeCAD with it's limitations. I've gone the latter route . There are some mid-priced options and Autodesk Inventor Fusion is free in the AppStore. But Fusion has been buggy in my experience (crashes often), so I haven't used it for anything I've modeled.

[Eaglezsoar]

If you're a Mac user, your parametric design tool choices are gonna suck really hard.

g.

So our options are suck really hard Windoze or suck really hard Mac tools? That really sucks!

[Batteau62]

I hate to say it(loooong time mac user)but the Windows version of Fusion is much stabler. I've used it quite a bit. I've also tried 360, The web enabled thing kinda weirds me out though, don't know why?

[dpmacri]

I hate to say it(loooong time mac user)but the Windows version of Fusion is much stabler. I've used it quite a bit. I've also tried 360, The web enabled thing kinda weirds me out though, don't know why?

I started to try 360 as well but didn't like having things stored "in the cloud". Not that I'm making anything anyone would care about, but it bothered me as well -- I want to have MY data stored where I want it

[neurascenic]

360, I don't like for the same reason.

I am not a fan of the Cloud as a whole. Or, I guess I should clarify: Clouds run by others. Where, they have my stuff, own my stuff etc... There seems to be a tug-o-war against master control and open Control. all too often, master control in the guise of openness (thingiverse)

There is also, too much iffyness about such things. Companies change terms and policies all the time. Add restrictions, and drop capabilities. Google pulls this crap all the time. They dabble in something, get people excited (maybe not enough people) and they drop it. Can't bring myself to using (and depending) on google docs for this reason.

Logmein, just pulled their free accounts with only a 7 day warning. Screwing out people who bought their mobile app (They are giving a 6 month extension to those) *

not to say they were wrong in doing so, just saying that there is no way to trust the future terms, conditions, and usable options of such a system. And when Data is king, that has huge potential to screw.

At least when you have the software, you have it, have rights to your own content.

Speaking of, There is a movement for 3D objects to be on a shared network instead of the thingivers type monopolies. I do hope this takes off! Guess the trick for this kind of thing, is, not everybody has their own server access to post files.

[geneb]

The most important thing you have to remember is that if you don't physically control the machine your data is stored on, it's not your data.

The reality is that there's not enough of a user base with MacOS (nor industry demand for that matter) for the major tool vendors to spend the R&D money on the platform. It's going to be a very long time (if ever) before you see a commercial grade tool for MacOS.

My suggestion is to build yourself a cheap Win7 box and grab Design Spark Mechanical. Barring that, a Linux box with FreeCAD.

g.

[dpmacri]

The most important thing you have to remember is that if you don't physically control the machine your data is stored on, it's not your data.

The reality is that there's not enough of a user base with MacOS (nor industry demand for that matter) for the major tool vendors to spend the R&D money on the platform. It's going to be a very long time (if ever) before you see a commercial grade tool for MacOS.

My suggestion is to build yourself a cheap Win7 box and grab Design Spark Mechanical. Barring that, a Linux box with FreeCAD.

g.

Actually, FreeCAD on Mac works fine (although I haven't compared to Linux/Windows) But you're correct about the lack of industry interest in use Macs for CAD, sadly

[Captain Starfish]

Meh, it's all pain vs gain.

Given that I'm relatively comfortable with AutoCAD I don't see sufficient gain for the amazing amount of pain playing with a Windows env again. And no-one yet has convinced me that it's an ACAD limitation rather than an STL issue.

So I guess I'll stick with what I have for now.