Cloud Animation

[composerman]

Hello,

I want to create some animated skies and I think I have figured out how to move the cloud layer(s) across the sky, but how do I make the clouds evolve as they move?

Thanks,

Troy

[Oshyan]

There are a couple of options at present. You can try the new (as of Terragen 3) "4D noise" option under the Animation tab of your cloud Density Shader. Enable the check box "4D Noise" and then adjust the noise speed parameter to your preference. The other main option is to Translate the noise function itself in the Y (up) direction. What this does is move the noise shader relative to the cloud plane, while keeping the cloud layer vertically consistent, which results in a surprisingly effective "evolving cloud" movement, as the features in the noise function grow and shrink while the noise pattern is translated through space. It's harder to explain than to try. There are some other threads discussing this around on the forums as well. A very fast version of the effect can be seen here (it can be made more realistic, especially with lateral motion): https://www.youtube.com/watch?v=Q_xzIJUbAnw

Others have tried things like animating the Warp amount, shown here: http://vimeo.com/36859915

- Oshyan

[composerman]

Thanks Oshyan, I'll give that a try. I am going to be creating these as spherical panoramas that I can project into a circular fisheye. I have noticed a slight seam when I bring the spherical image into Lightwave's textured environment. I don't have the same problems with other spherical pans from other software packages. Is there a setting in TG3 that will help eliminate or reduce that?

Thanks,

Troy

[bigben]

A cloud animation effect I like is to use a fractal warp shader on the cloud's power fractal and then animate the 2 powerfractals in opposite directions. Cloud's fractal up, warp fractal down. Here's a very short sequence (no horizontal movement)  I suaully start by duplicating the cloud fractal and then try different random seeds for the warping.

Haven't tried 4D noise yet.

To get rid of the seam point the camera straight up. That will move the sky away from the left/right edges and you'll be able to get a clean fisheye image of the sky

[Oshyan]

That's promising bigben. There are certainly a number of different approaches to this. I think one could combine several for a really good, realistic effect. But really clouds do move in many different ways too...

- Oshyan

[bigben]

Thanks Oshyan. Yes clouds do ove in many different ways.

I also thought of another advantage to rendering with the camera pointing straight up in this case. If the aim is just a fisheye image from the horizon up, you can crop the left and right side of the render by 24% to cut the render time down (technically 25% but a little margin for interpolation can't hurt).

[composerman]

Thanks for the tips. I finally had some time and I tried your sample scene and then made one of my own. Pointing the camera to the zenith got rid of the seams and also cut the render times significantly by cropping the sides.  I'm still playing around with the settings in the clouds panel and I think I am beginning to figure them out. What is the best way to move a cloud layer across the sky (i.e. from east to west..)?

Thanks,

Troy

[Oshyan]

Put a Transform Shader after/below your cloud Density Fractal (before it goes into the Cloud Shader's density shader input), then use the Transform function to move the noise function. The units are meters, so you're effectively moving the clouds (or rather the noise function that creates the cloud shape) across the sky  by n number of meters in each dimension. It's X, Y, Z coordinates, so to move horizontally you'd use X or Z as Y is "up" in Terragen.

- Oshyan