Bolean animation? Reveal/dissappear of objects

Hi guys/gals!

I’m trying to envision something, where a whole collection, or scene of objects goes by. On one end, they get revealed (some sort of reverse bolean?) and then after a prescribed length they disappear. Can you set something up, sort of like the dissolve for particles field? Or collision etc. for all objects in a collection perhaps?

Not sure if I’m clear about this explanation. =<

Thanks everyone!

Hope this can help.
:australia: :nerd_face:
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Hi there newb (I’m also a newb. LOL)! Yes, I’ve used something like this before in a previous project/test.

The problem with this is, if you have 50 objects, you can’t really bolean then? Or Bolean a collection? I may be wrong, but please correct me if I’m off. =>

You can select a number of objects … and you know how in blender you have an object that’s more highlighted than the rest - it has a brighter highlight and it’s probably the last object selected? If THAT object has a boolean you can copy the boo mod to all the others with ctrl-l link modifiers.

Doing this with 50 odd objects does sound like a way to crash Blender, though. Could you just have them fly through a plane with a holdout material on it?

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Well the truth of the matter is that I’m most likely no more advanced than you are but if you join this forum site ( Blendermania) Alex Cordabarn will be more than happy to help you with any problems since he made this tutorial in the first place.

:australia: :nerd_face:

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That sounds interesting… As mentioned, I’m a bit of a newb, so I’ve not come across a ‘holdout’ material? What is involved with that?

So as an example (like yogyog was saying) imagine you had a fleet of spacecraft. Then you wanted them all to disappear through a portal/solid plane, then possibly re-appearing at another spot from a solid plane. Pretty much think the game Portal, but with fleets of spacecraft ‘rezzing’ or materializing from a plane. That’s kinda what I’m going for.

Possibly, some sort of clipping plane?

Thanks again everyone!

The latest boolean in the 2.91alpha has the option to use a collection as the Boolean operand.

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Oo… that’s awesome howardt! When is 2.91 Alpha (or what not) being rolled out to a more stable version? It’s so hard to keep track of the versions. LOL.

There are a lot of different ways to do this-- as mentioned, booleans, or holdouts, or compositing.

The first thing I’d consider, though, would be using an empty to define texture coordinates, in order to mix with a transparency shader:

Oh, that’s a cool idea! Should be cool for making shrinkwrap targets…

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Huh… interesting… bandages, a couple of questions:

  • is this a more ‘efficient’ way of doing it? I like this idea… I also don’t have to wait for a stable 2.91. LOL.
  • will it work with a collection of objects?
  • Would you mind sharing a .blend file to check out?

Everything you need is shown there in the pic. What I suggested is very high performance, much better than booleans, and without the topology issues that booleans create, but there’s the potential for a bit of tedium if you have a bazillion materials, as every mat needs the mix-with-transparency bit (although that can be node grouped if you want, for easier editability.) It’s also previewable, unlike compositing techniques. Lets you use a background (or have unaffected objects) unlike a holdout plane.

But I guess I haven’t closed that file yet, so objtransp.blend (196.9 KB) if it helps.

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You are likely better off with bandages’ solution. But to answer your question, 2.91 is scheduled for release on Nov 24, 2020.

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Thank you to everyone!!! Such a wonderful warm and SUPER HELPFUL community. I now have a bag of tricks to try getting my project that I’m visualizing to work.

Thanks all!!!

That’s so cool… just playing around with your blend file Bandages! A couple of questions on this cool solution.

  • Is it possible to make the alpha clip a ‘solid’? So that the empty clips the shape, but then perhaps has everything that intersects becomes a solid red, or orange, or what not?
  • Also can you have 2 separate empties? Perhaps one on one side, and one on another side? So in other words, if you have a sandwich and you take a bite out of one side, then the other side, both show up?

Thank you again!

No, not possible with the technique I demonstrated.

Sure. Check from two different objects, via two sets, and then set alpha to be the math/minimum of the two.

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Very cool as always Bandages! So I know with Booleans, you can have a material that is ‘solid’ for the intersection (I’ve feebly did it one time), but with the empty technique it won’t allow for that ‘cut away’ or solid look I guess? So pretty much it’ll work only if you have the transparency material at right angles then? Otherwise it would show the inside of the mesh I suppose…