I had an idea on how to give some more control over booleans by being able to have a face sub-object selection before doing a union or difference. Then the boolean will only cut objects using the selected faces. It basically gives subset control over the boolean.


Here's an example - here are 2 solids, a hollowed out box and a separate cylinder object sticking through it. With just one face of the box selected and the cylinder selected:




Then doing a boolean union will only cut with that box face, making this result:




Here's another example, a thickened slab with spheres sticking out of it, the spheres are sticking out both sides but if you only want the result to go on one side, select just that face of the slab and the spheres, then a boolean union will do this:






And with boolean difference - here there are 2 vertical faces of the box selected (both the outer one and the inside one on the same wall):



Then boolean difference using the circles as cutting objects does this:




Here's another example, one solid like this:



And then a sphere sitting over top of it:



With just the cylinder face of the main object selected and then doing boolean difference with the sphere as the cutter:






Or with the inverse, all faces except the cylinder selected, then boolean difference:






It seems to be working well so I think it will be a new feature for the next v3 beta.


- Michael

It should make stuff like this more convienent - say you've got this thing:




And you want to make a handle coming off of it, instead of having to kind of carefully form the handle so it only sticks into just the side wall of the oval you can just make it stick through a ways:




Then if you select the outer face of the oval solid and the entire box solid:




Doing a boolean union will give this:




- Michael

A solid and a cutting line:



If just these faces of the solid are selected and then boolean difference with the line:



Only those faces get cut:



- Michael

Great idea! That would make a lot of stuff faster (even if it's already really fast to work in MoI3D)

I can see many uses for this Michael, especially in the jewelry sector. It will be a major time saver, and will make detailing a much easier process.

I like this idea a lot!

Martin Spencer-Ford

Michael,
In your hollowed out oval example, what happens if you do a boolean difference with just the outside face and the retangular thing? Does it create a hole in just that face?

Hi Michael,

Very nice addition to the Boolean set, from the screen shots it seems it'll save time not only in function also in modelling strategies.
I assume the regular Boolean function will still be in place?

-

Wow Michael! What an awesome "I shoulda had a V8" idea.

This is right up there with the essence of MoI's intuitive nature.
When I think about it, I'm always separating/re-joining and "pre-trimming" objects due to selective trimming issues.

Great work!
eric

@beanworks

> In your hollowed out oval example, what happens if you do a boolean difference
> with just the outside face and the retangular thing? Does it create a hole in just that face?

Yeah it will cut just the outside face, but then you'll be left with a somewhat weird result where the part of the box that was towards the inside of that face will be connected to it but that box piece will just be overlapping with the other inside pieces. It would look like this, where the only common edge between the box and the oval will be at that outside face:



You would not want to leave the object in that state because it's self-intersecting with some of its surfaces just sticking into each other instead of coming to common edges.

If you wanted to cut just the outside face and not leave any part of the box behind at all, that would mean the end result would not be a solid anymore. But you can get that type of result if you want by using the Edit > Trim command instead of a boolean - Trim only cuts the surface skin of objects and it already allows you to trim a face sub selection, using Trim would give this type of result:




If you want to cut an object and leave no pieces of the cutting object in the final result (no "side walls" or anything), then Trim can do that. The difference between Trim and Booleans is that booleans try to combine pieces of both objects together in the final result, to try and make the end result a solid.

- Michael

@Danny

> I assume the regular Boolean function will still be in place?

Yup, the regular Booleans are same as they were - this is just an extension to them for the case where face sub-objects are selected.

Previously booleans just did not work at all when only faces were selected, they worked only on an entire object selected.

I think I'd still like to add in something for "depth limited" booleans when using curves as cutting objects, but I think this method of limiting by face selection will probably be more convenient in many cases because there's no options to set, just make a face selection before doing the boolean.

- Michael

@Mike K4ICY

> This is right up there with the essence of MoI's intuitive nature.

Yup, it's a perfect example of the type of thing I'm always shooting for - adding more power to existing tools without gunking up the UI.

This type of thing where there's not any UI added at all is getting harder to come by!


> When I think about it, I'm always separating/re-joining and "pre-trimming" objects due
> to selective trimming issues.

Yup, I'm hoping this will help to avoid that type of prep work. The tricky part might be just remembering that you can do it this way instead.



It also really fits in nicely with the overall strategy of focusing on building simple extended shapes... So overall just a great fit.

- Michael

Tricky!

Another example:

A hollowed box with cylinders sticking through it:



With the inner faces selected:



Then boolean union will generate this:



With the outer faces selected:



Then boolean union will generate this instead:




Basically by making a face selection of just the outside it lets you make the booleans temporarily disregard the inner hole. And with a face selection of just the inside part it makes the booleans temporarily consider the outside to be extremely thick. But all just by making a selection.

- Michael

What happen if only 3 faces of the box are selected ?

Great Idea! This will be very useful.

It might not be very obvious without knowing about it though..
Maybe a message while doing the operation?

Marc

We need this out in the wild ASAP :)
It's a great feature to have on board!


Martin.

@Pilou,

> What happen if only 3 faces of the box are selected ?

If one side of the box was not selected then the cylinders would not be cut on that side, and the result would be some pieces still just sticking through the object, similar to what's described here: http://moi3d.com/forum/index.php?webtag=MOI&msg=6663.10

- Michael

@ Marc,

> Maybe a message while doing the operation?

I don't know... I just so dislike that type of "in your face" message in general...

- Michael

Hi Michael, I was thinking of an "inline" info, something like this:




Marc