gaurav Posted November 23, 2014 Share Posted November 23, 2014 Hi Guys,I am no optics or shading guy but interested in simulating light bending in a curve via changing refraction index smoothly.I guess in reality if it changes abruptly at the scale of visible spectrum, light splits resulting in scattering, which I don't want to happen. Could that heterogeneous medium be varying fog volume ? Can it be achieved with existing Plausible Shading models ?Very new to shading / Rendering so any help, pointers appreciated.Thanks, -GM Quote Link to comment Share on other sites More sharing options...
eetu Posted November 23, 2014 Share Posted November 23, 2014 I don't think you can get bendy light behaviour with any of the mainstream renderers. Double Negative wrote their own bendy light renderer for Interstellar, but that did take other relativistic effects into account as well. I suppose you could simulate it with having lots of isosurface shells with gradually higher indices of refraction, but that would of course get quite slow quite fast.. Thinking about the physics I would've expected the color dispersion to be the same regardless of how suddenly the direction changes. After a little bit of reading I'm no longer that sure. Seems like it's at least possible to manufacture gradient index lenses where the dispersion effects are independent from the refraction effects, which is quite weird. For effects in nature I don't know - at least I don't recall seeing any color aberrations in heat haze imagery for example. Also I don't see any aberrations in the dneg interstellar work, so I guess bending is fundamentally different then. Interesting:) Quote Link to comment Share on other sites More sharing options...
dennis.albus Posted November 23, 2014 Share Posted November 23, 2014 The first impulse would be to do it in a volume shader as that is evaluated at various steps along the ray. However, I think Mantra does not allow for changing the direction of the ray inside the volume shader context. As for Interstellar I guess it makes sense that we don't see dispersion effects, as gravitational lensing is not dependent on the wavelength. Quote Link to comment Share on other sites More sharing options...
eetu Posted November 24, 2014 Share Posted November 24, 2014 As for Interstellar I guess it makes sense that we don't see dispersion effects, as gravitational lensing is not dependent on the wavelength. Ah yeah of course, I wasn't thinking straight (ha). Quote Link to comment Share on other sites More sharing options...
gaurav Posted November 24, 2014 Author Share Posted November 24, 2014 (edited) Thanks for your replies. Interstellar article is neat. Edited November 24, 2014 by gaurav Quote Link to comment Share on other sites More sharing options...
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