Hi Michael,

On my first model, yes, sorry, my error is description of construction and what I used.

I made 2 rail sweep, then used planer to create solid. I attempted to add a small rad on that top edge but could only get a rad as small as 0.5(or 0.4). so I separated the surfaces then used the 2 top surfaces to produce the rad. I then tried to used the top of the rad produced to offset.


- Steve

Also since your new example actually does not have any gap, you can repeat the offset problem in v1 with it as well.

The only reason your original one did not repeat the problem in v1 was because it had that little gap in it.

- Michael

Hi Steve,



Right, so that edge with the little gap in it was not produced by sweep, it came from fillet.

It looks like the filleter wasn't able to make a completely great fillet surface there, if you separate it out and untrim it you can see the fillet surface itself actually has that gap in it.

So as far as I can tell there is nothing wrong with the sweep command there, it was a problem with fillet.

I think in v3 I may add some processing to automatically seal up curves for edges that are topologically closed like this.

- Michael

Hi Steve, also with your new example the same technique I described earlier of splitting the curve up at some other point will make it offset properly.

I've attached an example here, with the edge split up at one other point. Now you can select the 2 edges and use offset on them and get an expected result in the particular zone where it was previously going crazy.

- Michael

Hi Michael,

>>So as far as I can tell there is nothing wrong with the sweep command there, it was a problem with fillet.<<


I find it strange that after I make the 2 rail sweep in Rhino, the fillet can be made in MOI. There is something not right here.




- Steve

Hi Steve, probably it's some difference in the tangent directions at the ends of the sweep between the Rhino one and the MoI one.

It is possible that Rhino does a better job ensuring that the end tangents on a single closed surface sweep like that are exactly in line with one another.

- Michael

Hi Michael,

I will have to be cautious or avoid these types of closed sweeps in MOI.


- Steve