Hi Michael,

I'm trying to use the Inset command with the groove option on the attached model, on the face shown in the picture, the result wasn't what I was expecting, it seems to take the chamfered edge as reference and creates an undercut on one side of the groove and chamfers the opposing side of the groove. Is this how Inset is intended to work as I haven't used it very often.



Cheers

Hi Danny, yeah that is how Inset is intended to work - it's related to offsetting of the surrounding surfaces, so the result kind of takes on the shape of the surrounding pieces.

So for example a starting piece like this:



Will produce a protrusion like this where the protruded shape has the same angle from the outermost pieces:



Also because Inset uses an offset of the surrounding pieces to form the shape, it allows for things like this:





If it instead tried to make a shape that went only like an extrusion in one fixed direction like you were thinking about, multi-face inset things like this would not really be possible, because there are multiple directions involved not just a single overall fixed direction.

- Michael

Hi Danny, another way to think of it is that inset tries to maintain a kind of constant "wall thickness".

If it did a straight extrusion in your case, that would lead to an inconsistent thickness with respect to the chamfer surface. I guess you would like for it to pretend that chamfer was not actually there at all and instead focus on maintaining thickness with the rest of the cylinder, but MoI does not know how to ignore some feature surfaces like that.

I guess what you might want to do is adjust the order of your operations - do the inset first on the plain cylinder and then add the chamfer after that instead of pre-chamfering it.

- Michael

Hi Danny,
You before inset the cilinder and then chamfer it




FiL

Another example, here you can see how Inset is able to work off of more generic shapes like a curved surface:





That's another kind of thing that wouldn't work if it tried to do just a straight single-direction extrusion from the originating surface instead of using a surface offset of the originating surface with offsets of the surrounding pieces to cut it.

Some other interesting variations on this one - here with grooved enabled:



Here with grooved + expand - kind of puts a piping around the outside edge as a separate solid:



- Michael

Thanks for the detailed explanation Michael, as usual.

I get the logic behind inset now, as for reordering the modelling strategy, it's a bit more difficult when you have a moment of inspiration and the groove is an after thought :)

Cheers, also thanks for the input FiL

Hi Danny, maybe if just 1 planar face was selected, I could make an additional "Extrude" checkbox option that would show up in that case that would make it go straight like that.

Could be a little confusing because in some cases like boxes the result is the same between offset and extrusion, so there would be no difference when checking that option for cases like that.

But that could be a potential improvement to Inset.

- Michael

> That could be a potential improvement to Inset.

That sounds like a good idea Michael, I see your frame of mind is expanding the current toolset, cool!

Cheers

Hi Michael if you shell sphere you get 2 spheres one inside the other and that is a Groop!!!!!!!!!!! when you select you select the 2 sphere
and you can separate them with the Separate Command!

Hi lyes,

> Hi Michael if you shell sphere you get 2 spheres one
> inside the other and that is a Groop!!!!!!!!!!!

That's not exactly a group - the 2 spheres in that case actually make up 1 solid that has an internal cavity in it, like a hollow sphere.

The inner sphere in that case is the boundary of the interior void area.

If you do a boolean with a line to cut a sphere like that and then move the pieces you will more easily see that it is a solid with wall thickness.

- Michael

Hi Michael

Grooping 2 solids to make one solid is that what you saying

Hi lyes,

> Grooping 2 solids to make one solid is that what you saying

Yup, but it's more than just a simple group because in this case the inner sphere knows that it is the boundary surface of the interior hollow region.

It's kind of like how you can take surfaces that touch at edges and join them together to make a connected solid - in a certain sense that is a type of grouping mechanism but it's more than just a simple group because there is additional connection information created with edges being joined to one another.

The hollow sphere case is similar to that, it's not just simply 2 surfaces in a group, it's a structural arrangement where there is a solid region that knows that it has the 2 surfaces set up as the boundaries of the region, making a kind of wall-thickness to the solid with a hollow empty area inside of it.

- Michael

Capito thank you