Hello to all
I've seen all the pretty pictures of clouds and get into problems trying to get my own clouds.
ID3 works fine but if I have two clouds in different z position, the cloud in background always renders in front. Maybe a small problem but I can't find my problem.
Thanks for help
Detlef
id3 clouds again
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- Simon
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Simon would be right and highlights one of the main limitations of fog (atmosphere) shaders in both Mantra and RenderMan (any micropoly renerer really): When using more than one fog object, they are composited in the final image in creation order (or at least in a way that isn't going to work in most cases).
The two best approaches are to:
1. render each cloud separately then composite them together later.
2. Combine both clouds in to a single fog shader.
The first method has the most possibilities as you can use a library approach to clouds. Generate a bunch of ifd files of clouds to disk then render out final images of each cloud. You can get a lot of mileage out of a nice ifd file. You can rotate the cloud in Y to get several different looking clouds.
The two best approaches are to:
1. render each cloud separately then composite them together later.
2. Combine both clouds in to a single fog shader.
The first method has the most possibilities as you can use a library approach to clouds. Generate a bunch of ifd files of clouds to disk then render out final images of each cloud. You can get a lot of mileage out of a nice ifd file. You can rotate the cloud in Y to get several different looking clouds.
There's at least one school like the old school!
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- lisux
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jeffThats the reason because I prefer to use a surface shader instead of a fog shader.
Clouds rendered with i3d and fog objects can't casti shadows. They can receive shadows but they can't cast. Since fog shaders are called after all the shading is done (surface and light shaders), there is no way in the renderer to do this.
The other reason is becasue you can use many fog objects without problems.
Like the beggining of the thread, many for shaders cause problems, many objects shaded with a surface shader that uses i3d for volumetric rendering works fine.
Un saludo
Best Regards
Pablo Giménez
Best Regards
Pablo Giménez
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- lisux
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winkelTake a look at this shader shipped with Houdi: VEX 3D Texture Cloud.
Hi lisux,
can you help me on my way? What do you mean with
“with a surface shader that uses i3d for volumetric rendering”
Usually I get the bounding box of my particle system, with metaballs copied on the particles. To get the bounding box use a Bound SOP after your metaballs.
And then shade the bounding box with the VEX 3D Texture Cloud. Try different lighting setups to get the corrects results.
Anyway to get the best from i3D I finally have to develop my own volumetric shader, unfortunately I don't have any of them here bcecause now I am mainly using sprites but I think there are some examples in the exchange.
Viewing the code from VEX 3D Texture Cloud is another good start, and ofcourse Jason's tutorial about i3D:
http://odforce.net/tips/i3d_intro_page1.php [odforce.net]
i3D is great for some effects but my opion is that are very limited and very hard to control, and if you need fine details in your volume you are going to need so much resolution that render times (for the 3D texture) are crazy.
Un saludo
Best Regards
Pablo Giménez
Best Regards
Pablo Giménez
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