Objects in Water & Wave Spray Technique

Hi all,

I’ve been distracted from Cog production recently because of paid work. That doesn’t mean I have been idle with concept work. I have been mulling over how to set large objects in water such as ocean liners or islands.

My ocean concepts work OK but as soon as an object is placed in the water an unrealistic sharp edge breaks the illusion.
http://www.cogfilms.com/images/OIW-norm-sm.jpg
After re-watching ‘Son of Kong’, (yes only just released on DVD along with King Kong 1933 and Mighty Jo Young) I noticed that Willis O’Brien used a simple blurred matt to create the island sinking beneath the waves. I thought a similar technique could be utilized in Blender.

http://www.cogfilms.com/images/OIW-blurrmask-sm.jpg

It was quite simple. Create a Black & White pass of the island (white) against the waves (black). Blur this in a photo program. Then map it back onto the island from the object ‘Camera’. Use this as an Alpha and low and behold you have a travelling matte that smoothly mixes the island into the ocean.

You will have to adjust the size and orientation of the mask to correctly size and position the mask to work.

You can even take it one stage further and offset the mask in time to give reasonable wave spray for an island at long to medium distance from the camera.

http://www.cogfilms.com/images/island-sm.jpg

Here’s a short concept animation:-

island_320x180.mov (QT 1.8Mb)

Enjoy.

Cog

Ah, you’ve done it again! Beautiful.

You can even take it one stage further and offset the mask in time to give reasonable wave spray for an island at long to medium distance from the camera.

I didn’t understand a word of this.

BTW, I could use those fast moving clouds for a WIP of mine.
Any tips?
P

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Hi vliegtuig,

The mask is a series of rendered images, the mask animation, with each image filename incrementing by 1, i.e. mask-001.png, mask-002.png etc. In the texture panel (F6) you can set a texture as image and select those numbered images (250 in my case). Don’t set movie but set the frames manually to 250, or whatever the number of images in your numbered sequence. When you render the image will be incremented at each frame render. You will also notice an offset selector under the frames setting. This allows you to start the image from any number. In my example I set it to 3 so that on render frame 1 image mask-003.png was used and so on. This means that the mask texture was 3 frames ahead of the actual waves and therefore gave that spray like effect preceding the wave itself.

Difficult to explain but I hope that makes it a bit clearer. I shall be including this and other techniques in my new ocean tutorial in January 2006.

Incredibly simple technique. A white cloud texture in the mist settings with a black background and its material IPO OfsZ and OfsY set to give the motion desired. I rendered this as a separate pass then used the sequence editor to combine the island and mist. I used a simple add command and adjusted the mix in the sequence IPO.

Cog

Hi all,

Here is some more information on how the concept was created following a question on another forum:-

How many layers/render passes are you combining to make this shot and what are they…and what are you using to combine them?

In the island example I used 3 render passes that I combined in Blender Sequencer. One pass was the B&W matte to map back onto the main island with ocean pass, so that was kind of composited within blender render. The second was the mist which was a separate render of a cloud texture in the mist settings. I then combined these two image sequences in the Blender sequence editor.

If I was doing this for a production shot I would probably separate out more layers such as:-

* Diffuse lighting
* Specular lighting
* Mist layer
* Rain layer
* Island Matte
* Sky layer
* FX such as lightning
* Secondary illumination for lightning

I often use Adobe Premiere or After Effects to merge my renders. Not because Blender Sequence Editor can’t do it but rather that I have these 2 packages and know how to use them. You can achieve almost anything from within Blender but sometimes these specialist packages are a bit quicker and can handle large files a little better. The important thing isn’t the fact that I use one package or another it’s that by creating separate layers I have complete control over how a shot will turn out without having to rerender everytime I want to change the colour or alter the mist level.

Cog

http://discusions.home.comcast.net/icons/icon_idea.gifOnly too obvious. Great idea. Thanks for putting it up on the forum.

That’s amazing. Looks really incredible! I can’t wait for the tutorial so I can actually understand it. :slight_smile:

Hi all,

I have added a side by side comparison showing how this technique can really help to blend objects into a water surface.

object-in-water_640x120.mov (QT 1.6Mb)

I’m sure it has other applications which I will continue to investigate for inclusion in my upcoming NEW OCEAN TECHNIQUES tutorial that will be published in the new Year.

Cog

I’m sure it has other applications which I will continue to investigate for inclusion in my upcoming NEW OCEAN TECHNIQUES tutorial that will be published in the new Year.

I, for one, am really looking forward to this! I just started working through your “Realistic Seascape” tutorial, and I am getting stumped on page 7, because the constraints panel is now different in v2.4. I am now lost before I even get started.

Keep on truckin’ Cog. We wait with baited breath.