Hi there,

i am very new to Moi.
The first thing I need is to import a 3dm model to convert it in MOI into an iges file to load it in Autodesk Inventor. :)
I exported a model out of Modo with the Rhino 3dm export plugin an tried to open it in Moi, but there is no mesh.
Maybe someone knows whats going on?

regards

Hi Misc,

Can you upload the file here...

Hi Anis,

thank you for your answer.
I am sorry but I can not upload the project file.
Instead I exported a simple primitive cube out of Modo which has the same effect.

Hope you can help me.

regards

I don't believe Modo is exporting a NURBS object in their 3DM file, they're probably exporting a Mesh object (which the 3dm format supports) which is strictly polygonal...

-Will

Hi Misc - the problem is what Will mentions above - your 3DM file contains polygon mesh data and not NURBS data.

MoI is a NURBS modeler and will only load NURBS data from a 3DM file, it does not work on polygon mesh type data.

There are many different kinds of ways to represent 3D models - every program does not work in the same way or on the same kind of data.

Modo works with a system called Polygon/Sub-d modeling, where objects are made up of a large number of little facets.

MoI works with a system called NURBS modeling which is totally different from that, it uses something more like big rubber sheets rather than small facets.

It's kind of similar to the difference between working with bitmap pixel data versus vector drawing data if you are familiar with those differences in 2D drawing programs.


It is possible to export from NURBS in MoI into polygons - MoI has a conversion process that it will do when you export to a format like OBJ or LWO, where it dices up the big NURBS surface sheets into little facets to make them into polygons.

But it is not easy to go the other way and try to take little facets and glue them together into large smooth sheets. It's kind of like how you can take apples and smash them into applesauce, but if you start with applesauce it is not easy to construct apples back from that.


So the normal direction to move models between MoI and Modo is to start with a model in MoI and then export it to Modo by conversion to polygons. Since Modo does not produce NURBS data it is not generally possible to go the reverse way like you are talking about here.


There are some specialized programs that deal with reverse engineering polygon mesh data into NURBS surfaces, check out this previous thread for some links to some different programs that work in that area:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2469.3

But probably your best bet is to use T-splines for Rhino (http://www.tsplines.com) which has a method in it which can convert a sub-d polygon control cage into NURBS surfaces, which can then be sent to a NURBS CAD program like MoI or Inventor.


But basically you're trying to convert between 2 very different representations of 3D data, it's not at all just a matter of saving to a different file format, the structure of the data itself is very different between polygons and NURBS.

- Michael

Hi Misc, also just to clarify - it is possible to store many different kinds of things in a 3DM file, such as NURBS objects, polygon mesh data, rendering lights, dimension lines, etc...

MoI does not work on these different kinds of data currently, it only deals with NURBS objects so it only reads that kind of data out of a 3DM file and not any of the other things which may have been stored in there.

- Michael

Just one more thing - the closest thing to importing polygon data into MoI currently is to get the polygons into OBJ format, and then use the OBJ to 3DM wireframe converter here:
http://moi3d.com/wiki/Resources#Obj23dmWireframe_converter

That converts all the polygon edges in the OBJ file into line segments in a 3DM file, which can then be loaded into MoI and used as a kind of wireframe reference to snap on to as a construction aid.

- Michael

Thank you all for the answers.

I didn't know that 3dm =|= 3dm thank you for the explanation!
Luckily I found a way to get my final project out of Modo into Moi.
I simply exported the scene as a dxf out of Modo, imported it into Allplan and from there I exported a 3dm Rhino File. :)
Moi can handle this 3dm file type and did an excellent job exporting it as an iges!
Would be cool if there will be a dxf or dwg import option in future versions.
The pdf import option is only for 2D pdf files? I tried a 3D PDF but it seems that it doesn't work.

regards

your original file has surfaces? and if yes you have always in moi?

very interesting workaround Misk :)

a) There is also a Import Rhino files TRANSLATOR for Inventor. http://labs.autodesk.com/utilities/rhino_import/ (no idea if it works)

b) Also in Rhino you can use comand MeshToNurbs then save and open in Moi :)

Hi Misc, sounds like you had an architectural type model.

That's kind of an exception to the regular rule, since the model in that case is made up only of flat pieces.

That situation can tend to transfer more easily between polygons and NURBS.

Often people who are using Modo are building curved surfaces instead of only flat things, that's when the differences get to be much larger since there are then a whole lot of little polygon facets that try to approximate a smooth surface.


> Would be cool if there will be a dxf or dwg import
> option in future versions.

I would like to do a DXF import in the future, but doing importers tends to be difficult and time consuming work so I'm not really sure exactly when it will happen.

If you can possibly send me some sample DXF file to moi@moi3d.com, that could help me to test with in the future.


> The pdf import option is only for 2D pdf files?

Yeah, it only tries to import 2D vector data from the PDF file.

I'm not sure if 3D PDF files can contain NURBS data, or if they are polygons only.

- Michael