Need help with planet renders

[eapilot]

Can anyone point me to helpful forum threads or tutorials to begin the process of making an image like this?  I am learning Terragen as a 3D skybox artist and matte painter who has used Vue and World Machine extensively. A friend suggested that I use a camera projection mask to get better control over the global  shape of the clouds.
I am also trying  to match a camera setup in Maya for the shot sequence.  I am assuming that I cannot move the planet in Terragen and that I will have offset the camera by 1000000 units on the z axis.

I hope to learn Terragen well enough to introduce as a new tool for production at my work.  I would mostly be using it primarily for planet images and skies.

Thanks!
[attachimg=1]

[Dune]

Did you try the search button and look up planetary clouds? There's lots of information in those threads. And perhaps here: http://www.store.nwdastore.com/catalog/search?keyword=clouds you'll find what you need.
Anyway, TG is great for clouds, that's for sure. Good luck!

[eapilot]

@ Dune, Thanks for the advice.  I have looked the NWDA store and I was considering getting NVSeal Global Clouds, although I was hoping to use the new global clouds from TG4 ( they are new, right?).   If they are as simplified as the easy clouds are to the TG3 clouds, with less parameters to tweak, that be preferable.  I don't need as many layered clouds as the NVSeal global Clouds, since I want to focus on the eye of the hurricane shape and reveal as much terrain as I can below them.
How does one achieve the vortex shape of the hurricane clouds in Terragen?  I have seen them several times.  From searching through the threads, it looks like you use a vortex vector node, right?  Now I am just trying to plug in fractals into various inputs on the vortex shader and see what I get!  So far it's not pretty.   TG4 tutorials cannot come fast enough.

[Dune]

For global clouds you need pretty big values first of all (and high clouds), also for the vortex warper. I haven't much experience with this global stuff, so perhaps someone who has can chime in, but I'd say testing it on a fractal on the planet itself is the fastest way to check where the warp is etc. And yes, the global clouds are new and already have these huge sizes.
In principle you'd have to hover and rightclick in the preview where you want your vortex eye, then copy that location into the vortex shader. But I'd don't really know if that works also on the side of a planet. That's all I can say, right now.

[Oshyan]

The image you referenced actually uses an image map derived from a real hurricane as a mask for a noise function which becomes the density shader. The mask was created in a simplistic fashion based on a real photo, turned to black and white, and then adjusted with levels, cloning, etc. to get the desired effect. You could also get a similar - though probably not as realistic and detailed - effect with the vortex shader.

- Oshyan

[eapilot]

Why make it more complicated?  I will use a mask.  I have never used the camera masking technique, but I'll try to figure it out.  I can just mask the density fractal that is generated with the global cloud layer? 

[eapilot]

@Oshyan Is this how the image map shader would be set up?  Has the blend shader been renamed as the mask shader?  So far I can't get it to work.  Attached are iamges of the node projections, the mask, and the result.  I add a global clouds layer and I did not adjust any of the parameters.

[Oshyan]

You can just use the image map as a Density Shader input if you'd like, though masking the fractal noise function will give you a more detailed-looking result in most cases.

When using an image map, the "projection" you use is critical. With the image you are using, I would suggest a "through camera" projection. However you probably cannot use the camera you are rendering with and get good results since the perspective and height are wrong for the image you have. So I would add a second camera, switch to it, and set the view such that you see more of the planet from a more downward/direct-facing angle. Use that as your Projection Camera with the image map shader set to Through Camera projection type. That should start to give you results...

- Oshyan

[eapilot]

I definitely want to mask the fractal noise function.  There's no point in rendering in Terragen if I'm not taking advantage of the procedural volumetric clouds. 

As for the Image Map Shader, I have it set to "through camera."  And the mask is the same dimension as the proj camera and render camera, which is a ratio  of 1.78.  I'm stil not sure why it isn't showing up.  Are there other parameters like coverage that should be tuned a certain way?

[Oshyan]

If you are masking the normal fractal cloud Density Shader (that is created when you create a cloud layer), then you will also need to make sure that you see cloud in this area when *not* masked. If you do, and you are using the Image Map Shader as a mask with Through Camera projection *and you have selected your current camera for projection camera*, then it should be working, even if the alignment may not be ideal. If you've checked all that and it's still not working you'll need to post a TGD for us to look at. If you'd rather share it privately you can send it to us at support AT planetside.co.uk

- Oshyan

[eapilot]

I resolved some of the issues but currently the image is still offset to the right.  For the sake of the test, the projection camera is a duplicate of the render camera, so if done correctly the mask should line up exactly.  I adjusted variable settings of the Projection camera and the Image Map Shader.  There are certain settings that I still don't understand.

For camera/perspective, do you alway want to have it set as vertical fov for projection?  It lines up better with that setting.

For Image Map Shader/Projection, Location, I set the camera to position lower left and set the size to the ratio of the picture frame.  If it was 1 to 1, the image was distorted (squeezed)

I still don't know why the projection it is offset to the right. 

attached it .tgd

[Dune]

You can choose in the image map shader where to set the 'pivot', I mean, you can also set it to central. That's why it's offset to the upper right.

[eapilot]

@Dune, by Pivot, do you mean Projection,Location/ Position Center?  That doesn't work.  I already tried that.  It moves the image to the bottom left, almost completely out of the frame.

[Dune]

That's what I mean indeed. But why would you use a camera setup, I think it's easier to use Y projection, unless you may need it very far from the pole. I made you a little setup I would use, hope this is what you need. Just import your tornado image (my drawn simple one is square, so you have to change the ratio).
With camera projection it's rather critical how you aim the camera (-90º or less or more depending on the angle needed).

[eapilot]

@Dune
Thanks for the advice.  I might try using the image map shader that way for another test but it still doesn't resolve the issue I am having with the camera projection method.  With camera projection, I will have direct control over the composition in a mostly procedural generated process.