Can MoI .3DM files go directly to SolidWorks and into CAM for tooling smoothed parts?

 From:  Michael Gibson
1789.6 In reply to 1789.1 
Hi Jeff, yes MoI should work for this but there are a few caveats.

Data transfer should work well – I think it was starting with SolidWorks version 2006 that it added the ability to import .3dm files as another way to bring NURBS data into SolidWorks.

The .3dm file format is also the Rhino file format, so it may be listed on things labeled as “Rhino”. Your contacts are most likely a lot more familiar with Rhino than MoI so when it comes time to send them data you probably want to tell them you are sending them a Rhino .3dm file that might make more sense to them.

Additionally MoI also supports the IGES (.igs) format which is another way that can be used to transfer accurate NURBS surface data to many different CAD programs including SolidWorks. But I would recommend .3dm instead, it will probably be a smoother transfer. Also with the next v2 beta STEP (.stp) and SAT format will be added as well which are additional NURBS-based formats.

The caveat part is that in general MoI is not really designed to be a replacement for SolidWorks, it is more focused on a different area of making some basic solid modeling CAD type tools work well for artists who do not have a technical CAD background.

There are some functions of SolidWorks that are specifically oriented towards injection molded plastic design and that are very useful for that kind of thing. One pretty big area is shelling which is a common thing done for those kinds of parts. MoI does have a basic shelling mechanism but the one in SolidWorks is much more robust and can handle a lot more complex shapes with pieces that run into each other, etc...

Another area is that SolidWorks has some processes that make it easy to add stuff like stabilization ribs, some structural details like that which are common to these kinds of parts.

In MoI you would have to kind of model those types of things individually. Not impossible, but if you have quite a lot of them to do it will take significantly less time to do it in SolidWorks.

One way that could work pretty well is to generate the overall shape in MoI and then send that over to your contacts that have SolidWorks and have them do some of the sort of "manufacturing details" on it like calculating the shelling and inserting stabilization ribs, etc... That could be an effective combo.

The data that you send over in this way will be "real" NURBS data so it will be way more viable for your contacts to use your data directly as a basis to work off, which is just not going to happen when you send them polygon data (other than to just generate the part directly by STL and not do any further editing of it).

Also you may be able to get a pretty good inexpensive toolset by also throwing ViaCAD into the mix along with MoI, it is an inexpensive (like $100) CAD program that does happen to have a pretty good shelling module. It is not as easy to use as MoI, but it could definitely come in handy for doing the shelling if that part becomes a problem for you in MoI.

Definitely MoI’s UI is the most friendly way to get started in on NURBS modeling.

NURBS modeling will probably feel pretty strange to you at first because it uses a very different approach than subd modeling – for example in subd you probably avoid boolean operations except as a last resort and maybe not even then, however Booleans in NURBS are an essential “bread & butter” type operation that you usually try to target as the primary way of operating.

If you’ve done 2D illustration work with drawing vector curves, that may help you get more of a feel – in NURBS modeling you frequently draw 2D profile shapes as ways to drive the modeling, either for generating surfaces using those profiles as inputs (sweeping, extruding, etc..) or also cutting things by 2D profiles.

I’ve got some tutorial videos here: which are intended to be an introduction to someone who does not have any NURBS background. I’d recommend giving a look over those to kind of get a feel for the workflow differences.

I may be able to give you some more detailed information if you can post some images of the types of things you want to create.

If your parts are pretty simple and don't have tons of ribs and fastener pieces to them, then it will be more likely that you could complete the whole finished design within MoI. The more of those kinds of things that you have then the more you will probably use MoI as the first stage design tool and then send the data downstream to have other people work on it some more to fill that stuff in.

- Michael