Are there any known bugs in that trim tool?

That trim tool works sometimes and just stops working for no reason. I know I am a beginner and before I have missed a lot of overlaps and gaps and therefore no trimming success. But with this model, I really don’t understand why it won’t work. I managed once BUT again I ended up with Naked Edges which I don’t understand. I have used a very nice and neat outline to revolve and extrude and yet I can’t get rid of the extruded parts.

  1. Why can’t I trim the extruded parts?
  2. If one take a look at that green outline, does it really make any sense to get naked edges from it?
  3. Why aren’t there any error information, when the trim tool won’t trim?

ReferenceModel1.4.3dm (237.7 KB)

If anybody could just take a fast glimpse of it i’d more than happy

You can use the “Intersect” command to analyze why trim fails.
In order for trim to work there needs to be a complete intersection that divides the object into at least 2 parts.

In your example the revolved polysurface can be trimmed because the intersection cuts all the way through, but on the extruded polysurface the intersection does not make it all the way to the edge . So the extruded polysurface can’t be trimmed.

Somehow the extruded polysurface extends .007 mm past the end of the curve that was used to make it. I’m not sure how you managed to do that. If you make a new extrusion from the curve in the file the trimming will work.

This might be something to dig into a little deeper. Just to make sure it’s not a bug instead of improper operator technique.

Jim. Thank you for that. Can I ask you, since you helped me with the outline. I did the revolve and the extrude and I trimmed it very nicely. Plus that arc that I had added on the right side. But when I checked with NakedEdges it showed my a lot of them, even after I tried to join. So my question is do naked edges always come from bad geomatry? if they do, how is that possible when the outline was perfect and the trimming went smoothly. Then it must be other things that affect that

Naked edges don’t necessarily mean bad geometry.

My assumption is that you are modeling what looks like a wrist watch.
Since the end result is to be symmetrical you are modeling only half and when you get the half done the plan is to use the mirror command to create the other half. Then the two halves will be joined. If that is what you are doing then it is expected that all the edges of the surfaces that are on the mirror plane will be naked edges. After the mirror you should end up with naked edges on both halves that match up so join will then get rid of all naked edges.

like this:
NewModelX2.3dm (239.1 KB)

I didn’t understand the arc you added on the right side it is separate from the main body. It won’t be able to join to the main body unless you create something additional to connect it or move it so that it intersects. If that is supposed to be part of the main body it would probably easiest to incorporate that feature in the profile curve that you use to make the extruded polysurface.

I couldn’t tell where you wanted a filet, but I suspect the problem is the two new surfaces in this file. Extract the 2 surfaces and look at the curvature graph.

You should be able to make a much simpler and smoother surface instead of those wrinkled ones. .