I have noticed the same problem with the past 2 updates! anyone else?

Matt

Hi Matt, Tim sent me the file through e-mail and it appears to be writing out an STL, but the mesh had some really long and skinny triangles in it which the Roland software on the other did not seem to like.

If you are running into the same problem, you may need to adjust some mesh settings to avoid really long and skinny triangles. To do this, when you save the STL file, use the little arrow on the lower left hand of the meshing dialog to open up the detailed settings, and then try entering a 1.0 in the "Aspect ratio limit" box.

That will divide polygons that have a wide aspect ratio (like for instance if one side is 17 times the the other side, that is an aspect ratio of 17:1 ) into smaller pieces until they try to approach more of a square shape. That is one way to avoid long and skinny triangles.

The other setting that you can also experiment with is the "Divide larger than:" setting - here you can enter a distance and any polygon that has an edge larger than this distance will get subdivided. So for instance if you put in 2.0 there, any edges longer than 2.0 units will get divided further, this can also help to reduce long skinny triangles.

I will see if I can tune up the mesher a little bit to try and avoid them somewhat more by default though.

- Michael

Hi Michael,

I have tried both these options although admittedly not at very small sizes and I still only get one piece of a model coming through. For instance I did a plaque with lettering and only got one letter, when others had very similar curves. I have tried it as an IGES file though and that seems OK so I will use that in future.
I am not really sure what the pro's and con's are of these different file formats, I am mostly used to using STL and DXF . Roland Modela doesn't use OBJ which seems popular. But I now have a solution!

regards Tim.

Hi Tim, maybe I misunderstood the nature of the problem. Does it not work with multiple objects under any circumstances?

For example if you create 2 boxes and save that to STL, do those 2 boxes come through or does only 1 box come through?

- Michael

Hi Michael,

I too have had a similar problem with exporting STL from MoI over the last two Betas, but I'd just thought it was me?
Has there been some kind of "tuning" of the STL export that has now changed the way that it used to work??

Previously, I'd create a ring design & then add supports for milling, but I didn't need to join them together.
Now what I've noticed is if the model is made up of several parts, it wont export a complete STL, where previously it did.
I'm selecting ALL the parts for export, but not ALL the parts will then be in the finished STL file.

For a "work around", I've now been Boolean Union all the parts together prior to exporting as an STL from MoI.

Interestingly, if I open the same MoI design with all separate parts in Rhino, I can export a complete STL from Rhino.

regards Colin

Hi Colin,

> Has there been some kind of "tuning" of the STL export that has now
> changed the way that it used to work??

Nope... Nothing has changed in that area for a while.

Are you also seeing this when importing into the Roland software? Or is it some other software package that you are trying to bring the .stl data into?

This might be due to the way that the Roland software interprets the STL file. There is a method that can be used to label different objects in the STL file. MoI uses this method to label each different object. I tried Rhino, and it looks like the difference is that Rhino does not label different objects, it puts everything within just one object group in the STL file.

I suppose that might be to work around problems or bugs in some STL readers that might not support multiple objects in one file. I could do the same thing (just lump all triangles together into one object) if that is the source of the problem.

- Michael

Hmmm, apparently this is a small mistake in MoI's STL output - there is a structure that looks like it is supposed to be used to label different objects, but apparently it is not supposed to be used this way.

So I should be able to fix this up easily for the next beta.

- Michael

This was definitely a bug in MoI's STL export when there were multiple objects involved.

I've fixed this for the next beta, and also switched to write the more compact "Binary" type of STL file variant by default instead of the plain text version. You can still write a plain text type if you want by changing a setting in the moi.ini file.

- Michael