Hi Michael,

In the drawing, you can see a flat plate-like object with a middle piece cut out of it. At least, it's supposed to be cut out. But when I try to select the middle piece to delete it, the whole thing always is selected. I tried to find where they were still connected, and create some cutting surfaces to disconnect them. You can see the cutting surfaces. They are there solely for this trimming/cutting operation. But they don't do the trick either. I suspect that I've done something squirrelly in creating the plate, or with the initial boolean diff that I used to cut the middle piece out. Please note that the sides of the hole that's supposed to be left, are at a non-right angle to the plate itself. This is important.

In any event, can you help me to get that middle piece out of there? I hope that I've explained everything well enough, and that the elements of the drawing are easy to understant.

Thanks,
Mark

Hi Mark, it looks like there is a little tiny thin area connecting the 2 pieces together in this area here:





As best I can tell, the sloped in cutting pieces were possibly not quite fully aligned in that one spot there.

It's possible to remove the inner piece by selecting some faces of the model and then using the regular Delete command. To select a face, click on the object a second time - the first click will select it with "whole object" selection, and then when you go mouse over the object some more you will see edge and face sub-objects selected. Then when you click on it a second time you will then select an edge or a face. In this case you want to select faces, and click on the pieces of the inner part that you want to remove - once you have them selected (it's easiest to do this a few at a time usually) then push the Delete button or the Delete key on the keyboard to remove those faces.

Edges have selection priority so if you have your mouse close to an edge, the edge will be targeted and not the face - when that happens it means you have to zoom in some more so you can find a good area to click on the face that is not right next to an edge.

So anyway, that's the process you can use to just eliminate some faces from a model.

The problem will be after you're done eliminating all the inside faces there will be an open hole in that little area where the cuts were not quite fully aligned and where the pieces used to be connected to one another, and you'll probably need to build a surface to fill in what will be an open hole there.

- Michael

Hi Mark, so there are a few different little slivery surfaces in that area shown above, it's kind of a mess in that spot. But the area on the opposite side is completely clean. Since it looks like this piece is supposed to be symmetrical probably the easiest way to finish it would be to cut it in half with the Trim command and mirror the good half and then join those pieces together, all done after deleting the faces that you don't want for the inner portion.

.... But also looking at it a bit more the piece seems to be slightly rotated, like the top edge is not completely flat going along the x axis, it's like 1 degree rotated from horizontal. So that could potentially complicate making a good mirror of it.

- Michael

Hi Mark, I've attached here a finished version - I used the steps I described above to select and then delete the faces for the inner portion.

Then I drew in a dividing line from the midpoint of the top edge to the midpoint of the bottom arc, which is not an exact vertical line though because the shape is slightly rotated. Then using that line I used the Edit > Trim command to slice the object into 2 half pieces, deleted the half with the messy area, then mirrored the good half and then joined the mirrored pieces together to make a solid.

Hopefully this is the result you were trying to get.

- Michael