Feature Request - I've been using MOI for 3d printing and it is awesome and does great exports to STL files. Would it be possible for MOI to be able to import STL files so that we could support the entire life-cycle of 3d printing?

Imagine being able to download ANY file off of Thingverse and modify it and print it....it would be a great boost for my workflow. I can really see MOI being able to excel in that niche.

I understand if it's not possible but I love MOI and figured it wouldn't hurt to ask. :-)

Best, Nicholas

Hi Nicholas,
I'll go along with your wish. There are a large number of models at Thingivers that can be used with minor changes. Unfortunately not every 3D program can process the STL files.
I myself have published a lot of STL files of models (of course constructed with MoI ;-)) there.
Greetings
-moritz

Hi Nicholas & moritz, sorry but importing STL files is not likely to be added to MoI anytime soon. The reason is that STL files only contain triangle mesh data, not CAD surfaces are solids like MoI is designed to work with at modeling time.

STL is not really designed to be a format for translating model data between CAD programs, it's meant to be used for transfer to a 3D printer only.

- Michael

Hi Michael, what a pity - thanks for the answer anyway.
-moritz

Thanks, Michaeel. I thought it might be a long shot. :-) The workflow I've found (but yet to test) is to take the STL into FreeCAD, convert it to a Step file, and then import that. I was just hoping to skip that middle process. Thanks a lot for your quick answer! Best, Nick

Hi Nick, the thing is that with that kind of transfer something like a sphere is going to come over as a whole bunch of little flat facets rather than a real sphere surface.

For many things that's just not going to be a very good result. But if that's what you want to do you might try the STL import plug-in from here:

http://moi3d.com/forum/index.php?webtag=MOI&msg=7046.6

or here:

http://moi3d.com/forum/index.php?webtag=MOI&msg=8860.1

- Michael

Hi Michael,

All the FEA programs I have used will only let you export the deformed geometry as a stl file. I import it into CAD to manually rebuild the CAD geometry. Unfortunately, FEA programs don't export the deformed geometry as a step file. That would save me a ton of work. But it would be nice to have as an option to import stl files. I just use them as a reference. So I don't need to do any actual CAD work with it. Just thought I'd add my two sense. For me, it would be useful to have.

Anthony

Agreed about it being a pity - I'd always assumed STL files were quite similar to OBJ files.
I suppose the way around this would be to find a file translator to go from STL to OBJ and bring it in that way.

Loving MoI V4.


Cheers, Martin.

Hi Martin, pretty much the only similarity between STL file and OBJ files are that they are both polygon file formats.

STL files are very bare bones and were only designed for sending data to a 3D printer, not as a way to store models for working on.

STL files are intended to contain only one solid in them, they don't have any material information, can only contain triangles, and don't even have a structure with an indexed shared vertex list. They are just a big list of triangles without any connectivity information.

They should not be used as your main file format for any kind of work in progress, you should only generate them as needed for 3D printing processing.


> I suppose the way around this would be to find a file translator to go from
> STL to OBJ and bring it in that way.

It isn't really just a problem of translation between file formats - STL files contain only triangle mesh data and MoI is not designed to work on triangle mesh data. Just translating the same not-applicable-to-MoI data between different formats will not really be a solution.

If you need to work on an object that is defined using triangle mesh data, you would want to use a polygon mesh editing program that is designed to work with that kind of data which MoI is not.

- Michael

Thanks for your detailed reply, Michael.
I really did believe STL & OBJ files were more similar than you have explained - I'll try not to make such assumptions in the future.


Martin.

Ok, I'm using the newest v4 beta and it looks quite fine, but Michael, are there still no improvements to the rendering of edges? Edges from shallow or thins parts still "shine through", which can be very irritating. Actually, this one of the downsides of MoI that bugs me for years now. :-(

Hi 3image, sorry no, no improvements yet for the "bleed through" display artifacts. It's a sensitive area and it would be easy to get the opposite problem of edges partially not displayed.

There is some more information here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4987.2

- Michael

Hi,
did anyone try to edit a STL by importing it to Blender > Export as OBJ > open that OBJ in SubD in MoI v4?

I do try, but on quite complex model (many triangles - but STL have only 7MB).
MoI open that for a loooooong time 2H+ and sometimes crashes near end.

Or any proven method/workaround for editing downloaded STL file???

Thanks

Hi Mr. Yuri, STL files contain only triangles. The MoI v4 SubD importer is only designed to import sub-d control cages from OBJ files, not dense non-subd structured triangle meshes.

So that's why the import is not working, it's not the right kind of data that the importer is meant to handle.

In general MoI is not designed to edit dense polygon mesh geometry, you would need to use a polygon editing program to do that kind of work not MoI.

- Michael

Hi Michael,
I already understand that MoI is not made to edit triangle meshes.
I thought that STL can be converted to SubD-friendly file that can be opened in MoI.
So the complex triangle mesh will be translated to something else that MoI can handle.

Hi Mr. Yuri, a SubD-friendly file is structured very differently than what you will have in an STL file. The STL file contains only triangles while a SubD file should have all or nearly all quads and be sparser.

It's not a matter of just packaging the data in a different file format, the actual structure of the polygons needs to be redone.

There is a process called "retopology" which can be used for that kind of process, usually it's a manual process where you sketch out a quad only structure over top of a denser triangle mesh. There are some tools like TopoGun that can be used for that and also ZBrush has an automatic process called ZRemesher that does that kind of thing as well.

- Michael

Hi Michael,

Her are some notes on v4.

PDF export crash report
Mac Beta version crashes on my side when exporting a rectangle to pdf.
I tried on OSX 10.9.5 and on another machine on 10.12.6 and both crash.
On win 8.1, with Parallels, it exports fine.
On Mac version 3, it also exports ok.

Artefacts subject
On another side, I would like to add to the recurring display artefacts subject.
While I appreciate the display speed when working and can live with its side effects,
I often use MoI with a projector to quickly demonstrate geometry and moldmaking concepts
and it would be nice to be able to temporarily toggle to display or snapshot without artefacts.

3D view rotation speed observations
Also, I find that in 3D view space rotation and zoom in/out seem slower in v4 ("bumpy"?) when the grid is visible.
Much smoother when grid is masked or when using Parallel (isometric) view.
However, in Parallel view, display artefacts are more apparent.

Globally, I really enjoy working with the new version and am looking forward to use dimensions and annotations.
Thanks for all the attention you are giving to the user experience!

Michel

Hi Michel, thanks for the v4 feedback!

re:
> PDF export crash report
> Mac Beta version crashes on my side when exporting a rectangle to pdf.
> I tried on OSX 10.9.5 and on another machine on 10.12.6 and both crash.

Was a crash report file generated? That would be under ~/Library/Logs/DiagnosticReports/

If one was generated could you please send it to me at moi@moi3d.com or post here?

One thing that you might check though is your setting for "Canvas megapixel resolution" in the PDF export options dialog when generating a hidden-line drawing. If that is set to a particularly large value but you do not have a corresponding very large amount of system memory then that could result in a crash currently. Since MoI v4 is 64-bit now the limit of how much memory it will try to consume has also been increased, that could be why you see a difference in behavior here between v3 and v4.

It takes up about 34 MB per megapixel and putting it at something like 1000 will consume about 34 GB.



re:
> 3D view rotation speed observations
> Also, I find that in 3D view space rotation and zoom in/out seem slower in v4 ("bumpy"?) when the grid is visible.
> Much smoother when grid is masked or when using Parallel (isometric) view.
> However, in Parallel view, display artefacts are more apparent.

What is your setting under Options > Grid > "Grid sections" ? The default is 150 but if you have changed that to put in a high value there that might cause these kinds of problems.


- Michael

Hi Michael,

re:
> 3D view rotation speed observations
>What is your setting under Options > Grid > "Grid sections" ? The default is 150 but if you have changed that to put in a high value there that might cause these kinds of problems.

My setting in Options > Grid > "Grid sections" was way too high !
I turned it down to 1000 and now it's working fluidly.
Thanks !

re:
> PDF export crash report
I just sent you a crash dump.
This one still a mystery to me.
The MacBookPro has 16gb of memory and the other machine I tried was an 8gb iMac.
When exporting lines (no solids or surfaces), the "Canvas megapixel resolution" option is not there.
However, when I select export a Solid, the "Canvas megapixel resolution" option is set to "30.0".

Michel

Hi Michel, thanks for sending the crash dump file. It appears to be a bug in converting a style name into a layer name for the PDF file.

Can you please send a .3dm file that will trigger the crash? That will help me to track down the bug.

- Michael