Hi rhodsey, thanks for posting the file. Yes, this definitely works better to separate out just the few objects that are involved rather than the whole 46Mb file!

For a file that large you pretty much need to use one of those file sharing systems like divshare, or Windows Live Skydrive.

But anyway, I can repeat the problem over here - it seems to be related to the somewhat large size in units, your object there is about 10,000 units away from the origin. If you switch to meters instead so that you don't have quite as large of numbers, the chamfering will then work a lot better on that shape.

In general it is pretty good to pick a unit system that will give you numbers more in the range of 0 to 3000 or so and not a whole lot larger than that, because MoI will typically do calculations to an accuracy of 0.001 units, and if your object is of a large size numerically like 20,000 units across or something like that, then this accuracy is actually too high and you can get things like intersection curves with way too many points in them. That could probably be the reason for your large file size as well.

I'd recommend using Meters or centimeters instead of millimeters for something of this size. That will keep you in a better numeric range.

I'll take a look and see if it is possible for chamfer to be tuned up in this case, but you will run into various other problems when working with larger numeric sizes, so it is best to avoid that.

- Michael