Animated clouds to Maya

Started by 3D Lunatic, September 18, 2017, 01:57:00 AM

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3D Lunatic

I don't have Terragen yet, but am interested in it.

I want to have fully 3D clouds, animated and evolving, in my Maya scene. Clouds that you can fly around and through. How do you integrate the clouds from Terragen to Maya? Do they somehow export in a way that's renderable in Maya's Arnold renderer?
Thanks for your replies.

Oshyan

Hi and welcome. You can't export Terragen's clouds to Maya and even if you could they would not render as well because we have specially developed volumetric cloud shading in Terragen. What you can do, and what many VFX companies do, is render the clouds in Terragen, with alpha channel, depth pass, and other render elements, and then simply composite those with your elements from other software like Maya, in your compositing app of choice (e.g. Nuke). Terragen 4 supports a pretty good set of render elements useful for compositing: http://planetside.co.uk/wiki/index.php?title=Render_Layers_and_Render_Elements

You can also import and export camera and lighting data in FBX (or Nuke .CHAN) format to match lighting and camera moves.

- Oshyan

3D Lunatic

Thanks for your reply, I'm just trying to wrap my head around the pipeline. I suppose you can import cameras, so that I can match the camera movement in Terragen to be exactly the same as in Maya, including all the camera attributes (FoV, focal distance etc.) - I'm pretty sure you can do that.

My question is, if I'm trying to render an animation in which a small airplane is playfully flying around and through clouds, big puffy clouds that resemble a landscape, how can I create the flight path of the airplane in Maya if I cannot see the clouds? I want the plane to fly around the clouds in a way that shows that the pilot is aware of the shape of the clouds. How can I do that if I cannot see the clouds in Maya?

Thanks for your help!

Oshyan

Yes, admittedly that is a harder situation to handle with the current lack of cloud import/export. If you can lock down the look of your cloud shapes (i.e. you do not need to adjust cloud shapes based on the path of the plane, but rather the other way around) as well as the camera path before you animate the plane, then you might be able to create a workflow where you finalize the Terragen clouds, render them out to a sequence along with a depth pass, and use those to setup your plane flight path. You'd have to do some work in compositing to get the correct occlusion of the plane behind clouds since there's no way to export out the clouds as a holdout object for Maya.

We are actively researching OpenVDB import/export for the future, which should help a lot with these kinds of projects.

- Oshyan

3D Lunatic

Oshyan, thank you for your reply.

Yes, I can animate the plane to the shape of the clouds, that's no problem. I just need some visual cue to tell me where the clouds are.

Is there a way to place some objects, such as boxes, in Terragen 4 to "block out" where the cloud is, then export these with the camera to Maya? I could then use the boxes to help me animate the path of the plane. Then I would delete the boxes, as they are only placeholders. It's a clumsy method, but better than nothing. I really want to take advantage of the fully 3D physical clouds in Terragen, and fly through them as you would fly through a canyon. Do you think this is a feasible way? I understand your method using a depth pass and doing it more in the compositing stage, but I really want to do it in 3D, and affect the flight path of the airplane based on the position of the clouds.

Thanks again for your expertise.

Oshyan

Unfortunately you can't create object placeholders or export the cloud bounding boxes at present. One option that just occurred to me is to take the cloud density shader and connect it to the terrain and then do a top-down render. This will get you an image that has the shapes of the clouds in it. You could then use this to drive displacement or possibly extrude shapes for cloud placeholders in Maya. Again it's a workaround but might be, er, workable. Although you'd need to be careful to match the vertical "slice" of the noise function that the clouds are taking, so you may have to use a Transform Input Shader to offset the noise function once applied to the terrain. Another modification to that would be if you need to get the actual height of the cloud density shader, you could feed it through the Shader input of a Heightfield Generate and then export that as EXR...

If any of those sound like promising options for your workflow I can provide an example file or two to show you what I mean more specifically, though I encourage you try setting it up yourself too.

- Oshyan

3D Lunatic

Oshyan,

Thank you for your suggestions. Perhaps I'm overthinking this. Would it be simplest and most efficient to:

(1) Create my terrain and clouds in Terragen.
(2) Animate a camera in Terragen.
(3) Render the animation as a sequence of frames.
(4) Export the camera into Unity.
(5) Apply the animation to the camera back plane.
(6) Add any other objects, such as aiplanes, etc.
(7) Render, composite, edit.

As the camera can be exported, I don't need to worry about camera tracking, that's done for me. I just need to make sure to occlude any aiplanes when they are behind clouds, which I can do in AfterEffects. What do you think about this workflow? The animation is basically done in Terragen, and any airplane paths in Maya will adhere to that animation, instead of vice versa. Make the planes adjust to the camera movement, not camera to the airplanes.

Oshyan

Yes, that could be a quite workable approach. You just need to make sure that the animation tools in Terragen will work for your needs. We have all the basic tools, but if you need more advanced functions/movements (e.g. to track a specific object), then you may find you need to work in Maya instead. I would definitely try the approach you describe though.

- Oshyan

3D Lunatic

Thank you for the numerous replies, I now feel confident to purchase Terragen and I'm looking forward to many hours of creating terrains and clouds!

Oshyan

Excellent, glad to hear it! We're always here should you have more questions as you work with Terragen on your productions.

- Oshyan