Floating Open Object

This is a tutorial for partially submerged object with an open face such as a crate or a boat.

This uses the boolean modifier to create a hole on the water the shape of the displaced object. The boolean modifier need an object with volume to work. I tried with a plane object but it doesn’t seem to work.

First add two cubes. Resize one of the cube as shown on picture 1. Rename the cube “water” and the other cube “box”.

Duplicate the box [Shift]+[D]. Resize it slightly bigger than the original box. Rename it boxfield. Parent boxfield to box. See picture 2.

Select water and goto Edit Buttons [F9]. Add boolean modifier. Select Union and type boxfield for object. See picture 3 and 4.

Hide boxfield to another layer [M]. Delete the top face of the box. Add your textures. Animate and enjoy. See picture 5.

See my YouTube example.


I dont really understand what this is for…

I’m guessing animations involving objects in water, boats, rubber duckies and stuff.

Any open (non solid) object floating object on water. Like a boats, crates, cups etc… Uploading an example on YouTube at the moment. A rubber ducky would be solid object so you don’t need to do this.

Actually COG had a technique that from what I recalled didn’t require booleans at all. just texture tricks. I could try to find it maybe…
Booleans are a bit tricky in this regard. Suppose you have denser and more detailed objects. I don’t dislike boolenas, I use them a lot, and if you plan your meshes a bit carefully you get clean results with more complex meshes as well, bit it’s still a bit tricky to work with. I’d really try to find that COG tutorial if I were you…

PS: WASN’t that tutorial mentioned in one of the blenderart magazines?!?!?!?! I think it was one about nodes or materials or something!!!

Couldn’t you use a boat with a transparent top face? That would make it a solid object.

I’ve been to Cog’s website I see the ocean previews, I see the crate floating on the water just like mine. It previews it but no tutorial.


How do you keep a water surface from passing through and apparently filling the hull. Well composite nodes can both achieve this as well as softening the transition from water to object.

Over the next few days I shall be publishing 2 new Cogs Quick tutorials covering both this, object in water composite node technique…

I see no tutorial on it.