Continuing our investigation into how to improve the construction of these clouds, Kaleb Goulding and I stumbled upon a solution initially pioneered by the creators of Paths of Hate. Damian Nenow gave a presentation during SIGGRAPH that includes a brief explanation of this method and its implementation in 3D Max.
Damian Nenow's SIGGRAPH presentation at Autodesk booth from Platige Image on Vimeo.
I: SETUP THE GEOMETRY
The workflow of his solution goes as follows:
I: SETUP THE GEOMETRY
1. Create a Low Poly Geo
2. Cover the Geo with Spheres
3. Merge them into one Geometry
4. Use Automatic Mapping to generate the UVs
II: CAPTURE LIGHTING INFORMATION
II: CAPTURE LIGHTING INFORMATION
5. Create a Simple Lighting Scheme using Global Illumination
6. Bake the lighting information into Light Maps
III: CAST LIGHTING INFORMATION INTO VERTEX COLOR DATA
III: CAST LIGHTING INFORMATION INTO VERTEX COLOR DATA
7. Convert the data from the light maps into Vertex Color Data
8. Expand the Vertex Color Data using Spherical Volumes
9. Cover the Geo with Grids to Project Sprite image onto
10. Transfer Vertex Color Data to the Sprites
Now, clouds are all about the lighting and translucency and so if we can still get that look without having to spend the time to render volumes over and over, it will not only save us time, but if we can mimic this solution it will give us a unique look for the film that will help it stand out.
So, we worked to mimic this solution in Houdini and this is what we came up with:
Now, clouds are all about the lighting and translucency and so if we can still get that look without having to spend the time to render volumes over and over, it will not only save us time, but if we can mimic this solution it will give us a unique look for the film that will help it stand out.
So, we worked to mimic this solution in Houdini and this is what we came up with:
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| Sprite Node Network |
The resulting render obviously isn't perfect, but the render times are significantly down to seconds per frame and the visual style is most distinctly evident even from this turn around.
