Importing CAD Models into Cinema 4D: MOI to Cinema 4D

Photo of Rod Ross

Instructor Rod Ross

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In this video we demonstrate the program MOI and show why it is a popular option for opening and exporting CAD files.

In this video we demonstrate the program MoI to open and export CAD files. We take a look at the programs export options and the topology and show why this is a popular program.



In this tutorial, we'll take a look at MoI. MoI is an inexpensive CAD program that has become a popular way to export CAD files. In this tutorial, we'll take our CAD model of a drill through MoI and into Cinema 4D. MoI will open files directly from Rhino, but not from programs like SolidWorks or other CAD programs, but it will open up other CAD types like IGES, STEP, and DXF. MoI is a drawing program but for this tutorial we'll focus mainly on its export capabilities. Okay, so here we are in MoI and I'll open up our drill model that we saved out of another CAD program as a STEP file. So I'll just go to "File" and then "Open" and here's the hammer drill STEP file. As you can see for the file types, MoI opens up Rhino files which is dot 3dm, IGES, SAT, STEP, Illustrator, PDF and DXF. I would recommend that you ask for STEP files. It's a newer translation format. So I'll open this file. Notice that the drill is on its side and that's because of MoI's coordinate system, but in this case when I export it to Cinema 4D, it would still be on its side. So I'm going to go ahead and rotate this before I export it. So I'll just select it all, then I'll go to transform. Click on rotate, and I'll click here for my center point, and then I'll go up here, and type in "90 degrees" for my angle. And now it's rotated, and I just want one view port so I'm going to come down here and here click on 3D then I'll zoom out. And then I'll deselect it all just by clicking to this side. I noticed that this cylinder doesn't have any fillets on it. So I'll go ahead and add that real quick before I export it to Cinema 4D. So I'll go to Construct, and then I'll click on Fillet. And then up here on the right, it says, "Select objects to fillet". So I'll select this object and then I'll say "Done," and for the radius I'm going to make that point one and say "OK." And now it has a fillet. So now I'll go ahead and export it. So we can bring it into Cinema 4D. Now there are two ways that I can export this. I can either use "Save as," which exports the whole file or I can use "Export" and then I'll be prompted to select the objects that I want to export. In this case I want to export the whole file so I'll use "Save as." So I'll go to "File" and then "Save as," and as you can see here's the file types that I can save as. MoI doesn't have its own file type so you have to choose one of these. To export out to Cinema 4D, the OBJ file type is recommended, but you could also use FBX. So I'll click on "OBJ" and I'll just name this "hammer drill," and that opens up the mesh export dialogue box. Keep in mind that MoI is only a 32-bit program. So if you have large or complex CAD files, you may not be able to open them or export them. On the dialogue box, the first thing you'll notice is a slider bar with fewer or more polygons. Of course, if you slide it to the right, that's going to give you more polygons and that means bigger file sizes and longer render times. So keep in mind how close your object will be when you're rendering it. In this case, we'll be rendering close ups with this model, so I'll want more polygons. Next, you'll you'll notice the output drop down box, and by default it shows N-gons, but it also gives you a choice of Quads and Triangles, and Triangles only. Choose the option that suits you best. I'm going to keep it on N-gons. Next there is a drop down box for display. By default it's on Shaded + edges, but there's also a choice of Shaded or Wireframe. This can be useful to show your object's topology, and how it will look in the scene. I'll leave it on Shaded + edges. Next is Weld vertices along edges. I would recommended keeping this checked unless you're going to break up the model in different chunks for editing or retopology. It could also be useful to leave it uncheck if you're going to be using sketch and tune, because an unwelded edge will leave an accent line. Otherwise, I would leave it checked. Next we have the angle control and that's the same thing as this slider bar up here except that it gives us a little more control because you can type in angles that won't be represented on this slider bar. One easy way to tell if you have enough segments on your model is to look for cylindrical objects like this knob or this handle here. If I were to type in "25" for my angle, you can see there aren't enough segments to make this look round, but I'll also take a look at this handle back here. There's obviously not enough segments to make this shape. So I'll change the angle to "5." And now you can see I have plenty of segments to make these make this look round. And now I have enough segments on my handle here also. Next is "Divide larger than," and that's just a way of adding segments to your model. So I'll start off with "5," and say "OK." Now you can see that's added extra segments to the model and by default that set to "Curved." So if you look at the curved areas of the model, you can see that's where it's added the segments. You also have a choice of "Planes" and "All." I'll change it to "All." Then you'll be able to see segments over the entire model. So now I'll change this back to "Curved" and let's make this "0" again. Now for "Avoid smaller than," that's a way to control mesh density in the smaller areas of your model like fillets. So I'll zoom in to this fillet and then I'll change this to ".5," and as you can see that would be very useful to control the density of your mesh. So I'll zoom back out. And for "Aspect ratio limit," that's another way to add segments to your model. I'll put a "1" in here and say "OK." And you can see how that's added segments to the model. You can use this in conjunction with "Divide larger than" to get the segments that you want. I'll change the aspect ratio limit back to "0." And we'll go ahead and export our model. Okay, now we've exported our model and we'll open it up in Cinema 4D. Now we're back in Cinema 4D and I'll open the file, and here's the hammer drill OBJ file. I'll open that, and the OBJ import dialogue box opens and I'll just keep these settings. And here's my CAD model from MoI. I'll click on "Display" and go to "Lines," and everything looks good the way we exported it from MoI. Now, just for a recap, some things that we need to keep in mind when exporting our CAD files is to keep the mesh density low. Only dense enough for the closest shot in your storyboard, keep your CAD files in case you need to export them again. Remember, if you're using any deformers on the model, make sure that you have the segments that you need. Make test renders of your models to make sure that you don't need to re-export them before you spend time texturing and setting up your UVs.
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