Use imported .obj to displace water?

[digitalis99]

I'm using Blender's Dynamic Paint to create some wake models for a project I'm working on.  I can output the baked wake in a couple different formats, and I'm trying to get them into TG2.  I've picked a frame in Blender that I like and output that as an .obj.  I imported that into TG2 with no errors, but I can't seem to apply the output to anything in the node network.  Is there something else I need to put between the .obj and the water shader to get this to work?  Does this even work at all?  Am I going about this all wrong?

Yes, I searched the forums, but couldn't find anything useful.  Everything was about applying displacement to imported .obj's, not the other way around.

[Matt]

We did something similar for the Paramount 100 Years logo: http://www.youtube.com/watch?v=JWb9v8OB8HA

You can't use an OBJ to displace another object, so what you need to do is actually render the OBJ as a piece of water. Bring the OBJ into Terragen and for its surface shader use a Water Shader or a Reflective Shader. You might want to render these water objects separately and comp them over the rest of the scene afterwards. If your imported water overlaps the native Terragen water, and if they are transparent, rendering them all in the same scene won't look right because you'll see one piece inside the other.

I'll look at my files to see if there's anything else you need to know.

Matt

[Matt]

I rendered all the water objects with ray traced objects ON, because ray traced mode allows the reflections to stay sharp while there's motion blur from the camera travelling across the water. (Maybe this isn't needed in your case.) In this setup I think there were some problems with the built-in wave fractals of the Water Shader when applied to the imported objects, so I set roughness to 0 and added ripples afterwards in the composite. But there might be a way to get this working.

[Dune]

For a wake such as that, isn't it easier to use a (photoshop) mask that travels along as a displacement map in the 'real' water?

[chris_x422]

You are right Ulco, you can use a mask or an image sequence for this form of displacement, but I've always found the mesh generation for fluid effects to be faster and more natural looking, at least in realflow. A simple mask in it's self would also look nowhere near as natural in animation.

[Dune]

Good to know, although I'm not into animation yet...