I've been doing some tests and needed to ask a question.

At the most basic level, Is there a difference or preference in the creation of a boolean diff surface with the diff object having a fillet or doing the fillet after the boolean.

Create a square. Create a smaller square to boolean out of the larger square.

a. I could fillet the smaller square .5 then boolean and have a pocket with the fillet's.

b. I could boolean the objects then fillet the edges of the pocket .5

Is this 6 of one half a dozen of the other?

Thanks

Hi Burr, either method should actually be fine if it produces the same shape that you want.

But I would probably tend to lean towards option b - to fillet afterwards.

That just keeps the boolean calculations to be more simple because there are fewer surfaces being intersected during the boolean operation.

Also some other operations such as shelling can have some difficulty being applied to already filleted objects, so it can just be a good policy in general to try and fillet last rather than earlier.

It's also not unusual to want to fillet some of the edges that are formed only after the boolean, like if you want to fillet the top edges of the pocket as well as the interior parts, like this:



For that you've got to do the boolean first as well.



If you want sharp edges on the top it should be fine either way really but since there are some other kinds of cases that need the filleting to be done later, doing it later is kind of more typical.


- Michael

fillet last. I've read you say that before. Not thinking.

Thanks.

Hi Burr, well really I guess any way that works is fine! :)

But yeah some particular things will work better last so that's not bad to kind of standardize on that.

- Michael

In most actual manufacturing it is usually done last as well.

Thanks Grendel. My brother (running the CNC) also prefers to do it with the tooling. I've been trying to show him the value in having a 3d model also to go with a 2d layout with pockets and profiles. Truth is our simple stuff does not require doing things with 3d parts. We dont do any pencil milling type stuff and it would just take longer.

I'm mostly learning from you guy's. When I see something I may wonder about. Like on those big assembly type models some do. I asked it what I saw were mostly "surfaces" to represent plastic "wall parts" or if it was actually modeled with thickness. For instance, with one of your coffe models. Is the pot body actually modeled at 1/16th thick chrome or just a surface to cover that area (If you punch a hole would there be 2 edges per surface or only one?)

Thanks again,
Burr