Hi Paul, thanks for sending me the file in e-mail.

So your problem is one of the last things I mentioned above - you don't have any NURBS surface data in that 3DM file, you only have polygon mesh objects.

Rhino supports several different kinds of data in 3DM files, things like NURBS, polygon meshes, dimensions & text, spotlights, etc… but MoI is focused only on NURBS modeling and will only read and write NURBS objects from a 3DM file and will not read in polygon mesh data that might be in the file.

But since you have the object as polygon mesh data already, it is actually ready to be imported directly into Modo without trying to bring it into MoI to convert it.


To bring the data into MoI you need to have the original CAD data, which will usually be in either an IGES or STEP file. That will contain the actual original NURBS spline surface data in it instead of a bunch of faceted polygons, and that spline data is what MoI is set up to be able to import.

MoI can _export_ to various mesh formats, at which time it will break the smooth spline surfaces down into polygonal facets to store as a polygon mesh, which you can then load into a polygon modeling program.

Typically you will want to do the mesh conversion in MoI instead of in the original CAD program itself, because MoI has a much better process for doing that part.


So you'll probably want to go back to whoever is sending you these files, and ask them to send you the original CAD data (preferably in both IGES and STEP formats) and not to send you only already triangulated polygon mesh data.

- Michael

Sounds like you should pop up a warning or error dialog, Michael when you try to export to a polygon format without there being any surface data available to mesh?

-Will

Hi Will, yeah that's on my "todo" list to put up an error message for this situation when there were only mesh objects in the file so that nothing was in the file that could be used by MoI.

I do kind of hate those "in your face" messages though, so I've been trying to think if there would be a better way to display these kinds of errors.

- Michael

Michael,

Can you "know that one is in it" and have some kind of "Reference object" import in? So like the scene browser would have an entry for "Non Editable Mesh object" or something with a "point" at it's bounds center (as opposed to an "Error")

Hi Burr,

> Can you "know that one is in it" and have some kind
> of "Reference object" import in?

Actually that does happen already - when opening a file that contains objects that MoI does not handle, they are actually stored in an internal table so that if you save back out again those objects can be written to the file instead of just lost. That's to try and enable "round tripping" of data in the 3DM file to help avoid data loss.

But there is no visual representation of them.


> So like the scene browser would have an entry for "Non
> Editable Mesh object" or something with a "point" at it's
> bounds center (as opposed to an "Error")

This would be quite a bit more work to make entries in the scene browser and visual representations of special non-editable objects.

I could certainly do that, but it's the age-old question - what other kinds of actual editing features would you like for me to sacrifice in order to spend time working on special stuff for non-editable "foreign" objects?

It's hard to justify spending much time on an area like this that does not really affect someone who is just modeling inside of MoI.

- Michael

Not really some kind of representation of the object, more like a "label" instead of an "Error". So since the objects exist and are being stored, and it really isnt an "error", just a label in the Scene browser that states "Stored mesh object" or something like that.

Anyway, it was just a thought.

Hi Burr, so normally in the Scene browser you can use the scene browser to select or hide or show things...

Would you expect for those operations to work on these special objects?

What about deleting them? It could be kind of frustrating if things showed up populating the scene browser but you had no way of actually doing the normal kinds of interactions with them.

I think that would likely open up a big can of worms with a lot of work trickling down from it.

- Michael

Got it. Short sightedness gets the best of me.

Hi Burr, well don't get me wrong I think it is a good idea.

It's just one of those ideas that is hard for me to implement because there is probably a fair amount of work involved.

- Michael

Well one thing you can do is perhaps limit the drop down format options depending on what's in the scene.

This way there wouldn't be any polygon export formats in the list if there wasn't any surfaces to mesh.

-Will

Hi Will,


Maybe... But that could just push the question off to a different one - then it would be "why isn't the file type I want in the list?", instead of "why didn't anything get written to the file?"

- Michael