I tried to remove a bevel from a model I received by deleting the bevel and retrimming the surfaces, but the new surfaces won't trim correctly. Is there a better approach to removing the bevel?

Hi Randy, it looks like the difficulty is that the adjacent surfaces have their underlying surfaces extending out a little bit from the original trim boundary, like here:




So those probably need to be trimmed to an isoparm, not directly to the other surface's edge. Or it might work to get the right edge after untrim if you run ShrinkTrimmedSrf on the outer ones before untrimming. I'll take a look and see if I can get this done.

- Michael

Then there seems to be a little bit of a gap on the outside boundaries as well, which is hard to tell without zooming in closely:






So if you tried to use the upper crossing curve as a cutter, it does not quite go all the way across the surface and that will make a weird messed up boundary like you're getting. You will also need to include the original side edge as a cutting object as well I think in order to get a good trim.

- Michael

Hi Randy, yeah Trim was very finicky on this object, I think that some of the edge curves meet each other or the surface by a slightly looser tolerance than what MoI is expecting. Either that or the narrow spacing of the outer boundary away from the underlying surface boundary is problematic.

I was able to get it to trim by using the "Isoparm" option of the Trim command to first slice off the narrow strips and then further trim it using the curves. So it took some fiddling and also I had to scale it down by 1/10 in size in order to join it and then scale back up again, my guess is it's probably built to a tolerance of 0.01 units rather than the 0.001 units that MoI more generally expects. For trying to re-use the same curves for a new trim that difference in original construction tolerance gets to be problematic.

Anyway the result I got is attached, hope this helps!

- Michael

Thanks, Michael! This model was originally created in what used to be called Pro/E by my client's engineers. After I import the STEP file I scale the model up 100x. You have helped me in the past and said that scaling up the model is the first step in solving trimming errors I was getting on import. I understand your explanation for scaling the model down by 1/10 before trimming, now.

From my experiences, most of the surfaces that I untrim from these models have this narrow spacing. In fact, I thought that was normal.

Am I on the right track for removing the fillet from the notch in the surfaces or is there an easier way to do it?

As a side note, I was able to speak with one of the engineers about a modification to a model I requested that they do on their end in"Pro/E." He said that when he tried to increase the size of a particular rounding his computer crashed. Wow! I thought that with a programs that costs thousands of dollars the engineers would be able to do whatever they like. Apparently I am not the only frustrated one. Heh, heh!

I love working in MoI! Keep up the good work!

-Randy

Hi Randy,

> Am I on the right track for removing the fillet from the notch in the surfaces or
> is there an easier way to do it?

You were on the right track and doing the right things - it's just that Trim was being finicky about these particular curves.

It's possible in this particular case that not scaling up initially after import might help... The thing that's a bit tricky about scaling is the gaps between things also scale up as well.

Over time I've moved more of MoI to work better on different sized objects, so it's possible that the past advice may not apply in all cases anymore... But it kind of depends on the particular situation.

- Michael