Hi Lars, Blend can sometimes be used for a hole like this, but right now Blend is limited to only working between 2 edges.

So if you have one big edge, this can be done by using Edit/Trim along with the "Add trim points" option to split the edge into 2 pieces, then you can use Blend between those 2 to make a kind of fill. But this may not behave well in an area of inflection curvature like you have in this case.

There isn't currently a way to merge edges that are already split up into smaller pieces into larger edges yet.

Probably right now your best bet would be to use a rectangle to trim out a bit more area and then do a Network on those rectangle edges (use Join to glue together small pieces into one curve where they cross the seam edge).

That's what I did for the attached hole_patched.zip file.

The result is not perfectly smooth, but it is pretty close. If you could find some way to get an additional proper guide curve running through the middle that would probably help get it closer. Also if you were a bit more careful than I was to make the rectangle a little smaller that would probably help some more too.

Sometimes it is helpful to use Edit/Separate to break your model apart into different pieces so it is easier to work on just one piece at a time for stuff like this, then use Edit/Join later on to glue it back together again.

I do have plans to add a different type of hole-patching mechanism in the future.

Hope this helps you for now though,

- Michael

Another technique that can sometimes be used is to put a little tiny disc into the center of the hole:



Then the edge of the disc and the edge of the hole can be selected:



And then Blend will create a surface there, which can be joined in:



If you have a split-up edge like you do on one side, you have to use Edit/Trim (with Add Trim points option) on the disc's outer edge to split it up into the same number of pieces as the hole and then do the blends with a pair of edges at a time.

- Michael

Hi Michael,

>So if you have one big edge, this can be done by using Edit/Trim along with the "Add trim points" option to split the edge into 2 pieces, then you can use Blend between those 2 to >make a kind of fill. But this may not behave well in an area of inflection curvature like you have in this case.

That's what happened to me, there were holes in the fill.

Hi Lars - those gaps are at a small size, I think smaller than the tolerance of 0.001 . Generally stuff in MoI is constructed to fit to a tolerance of 0.001 units, so it is not unusual to see gaps between things around that level of size.

If you select those pieces and use Join on them, they should join together and get a single common edge, which will in effect seal that gap.

If you need more accuracy on the construction of that piece, you will probably need to scale things up somewhat in size so that 0.001 units is an acceptable gap size.

But that blend should actually work to fill the hole if you join it with the other surface.

- Michael

Hi Michael, yes your right, it is very small gaps. I liked the idea with a small disk in the middle to blend with the outer hole. Had to try a few times, it wasn't that easy to align the disk correctly. Construction lines are really handy.

Thanks

/Lars

Hi Lars, here is some more information on how the rectangle solution works, it is probably the most simple method.

To start with I used Edit/Separate to break your shape apart into individual surfaces and then hid all them all except for the one that I wanted to work on:



I went to the side view which had the closest to a straight-on view of your hole and drew a square there:



If your square does not line up well with the hole, you may need to select it and then use Transform/Rotate on it so that it is aligned more evenly with the hole.

So now you have a surface and a square, it looks like this in the 3D view:



You can now select the surface, and run Edit/Trim, then select the square as the cutting object. The surface will be cut by the projection of the square and you can pick which pieces to remove, pick this piece to remove:



Now you have a square hole. However, it is bounded by 5 edges since this crosses a seam edge. Here is shown one of the pieces that was divided in 2:



You can't make a good Network surface out of 5 edges like this, you need to have 4 curves to make a simple Network surface. So you want to select these 2 edges:



Then use Edit/Join to create a new curve object that is made up of these 2 edges joined together.

Now deselect everything by clicking in space or pushing Esc, then select this new joined curve, and the 3 other edges:



Now with those 4 curves (the one joined curve, and then 3 edges of the hole), you can create a Network out of them:



If you can make this square not much larger than the original hole it will be a smoother fit.

- Michael

Great! I really couldn't go wrong there. It really produces a smooth fill.
Thanks!

/Lars