Earth ocean specular

[Juraj]

Hello

I have been wondering how to achieve shape of specular reflection that can be seen on photos of earth from space. Is anisotropy the only way to achieve this? Also how would you link camera's position to anisotropy rotation? (for example when significantly moving camera / sun)

Also can anisotropy reproduce this effect accurately? When I tried stronger anisotropy on sphere, the shape of specular started to becomy curved.

I think that this specular shape is caused by "miniature" displacement of ocean. But for this kind of scale I think it wouldn't be possible to displace ocean geometry.

 

 

Thanks,

Juraj

 

[Kardonn]

It wouldn't be anisotropy as much as just a very rich brdf with a long falloff tail.

You could start getting the look using the ggx specular node, and mixing a few together with differing roughness amounts on each until you start getting something like that.

Also remember those images are tonemapped and edited, so its hard to use them to figure out the actual linear response of earth's ocean specular from orbit.

You'd also want to layer in some nice procedural noise detail into the roughness. Not much, just vary it a few percent up and down so its not totally perfect.

Edited November 3, 2015 by Kardonn

[mestela]

 

quick play with layering 3 principled shaders; blue diffuse base, anistropic wideish spec with noise, and tight spec on top.

 

super lame clouds and atmos on top, has potential maybe?

 

ocean_test_v01.hipnc

[Juraj]

Thanks for your replies.

Stacking specular layers and playing with anisotropy seems to be the way to go.