Michael, The file is 16 megs and both email and this forum chokes on that size.

The file is on it way via www.yousendit.com.

Hi Dave, I got the file.

But unfortunately surfaces created in this way are basically unable to be intersected with other surfaces for things like boolean operations.

The bendy trailing edge is a really complex curve as far as sweep rails go - combined with a really dense profile curve, that has resulted in a very complex surface. That's why it is working so slow and the file size is so large, the surface is really dense with control points.

To see this, you can select it and use Edit / Separate to break it into individual surfaces. Then select one of them and use Edit/Show pts, you will see a really dense sea of points there...

You basically can't use sweep with such a complex bendy rail.... Well, you can use it, but the result is just not going to be boolean-able, it will have too much torquing and kind of folding over itself. It drives the intersector crazy to try and track all that when calculating the intersection with a different surface which is part of the calculations for booleans.

It is quite difficult to make a sort of subtly bubbling kind of surface like this in MoI, you've basically got some little wavy and ripply details. MoI's tools are more based around creating broader more gradually curved surfaces, not so much things with small detailed ripples and bumps in them.

I'd recommend doing this in a polygon-based subdivision modeler like Silo for instance, this kind of detailing is kind of closer to organic type modeling than industrial/mechanical style modeling...

Also like I mentioned in my other post, a system based more on raised relief work like ArtCAM would probably do a much easier job of this than MoI as well.

- Michael

Michael,
Just a note to show you my little success. Trying to get a home modeling and CNC station going, requires lots of learning.
Here's a result using the model you provided.

I'm still acquiring the proper bits for machining small parts like this one. The model is only 6 inches long in this case. The bits used were .062 diameter, flat bottomed.

Hi Dave, that looks like a good result!

Stuff that has more broadly curved pieces like that will be a lot more feasible to do in MoI.

Also, you'll probably notice that the one I sent to you should probably not bog down your machine as much as your other version, that's due to using not quite such a large quantity of points in the defining curves.

One thing you might also check into - it might be possible for 2.5D type cutting that your CNC software does not really need a fully finished solid. I mean that it might be able to work fine if you have separate pieces that just stick through each other in the model instead of being actually booleaned together.

If that's true, then you may have some more freedom to construct what would normally be considered "messy" surfaces, like stuff that folds around a lot, intersects itself, etc... - stuff that you would normally want to avoid since it won't boolean later on.

- Michael

Hi Dave & Michael,

I've had situations before where a model wouldn't Boolean together & I've still been able to machine it with my mill.
In these cases, I've selected all the parts & exported them out as an STL file for the CAM program.
I used the default export settings, but increased the slider to it's maximum, which I think is a value of "3".
All of these milled models have come out fine.

Obviously you couldn't do this with a model that's for RP or to be "wax printed" or "grown", as these processes require the model to be water tight or a complete solid.

Hope this helps, Colin