Microfacet Refractions

[jkunz07]

Hey,
 

Has anyone have any ideas on how to do something like this in Houdini/Mantra?

 

 

https://www.cs.cornell.edu/~srm/publications/EGSR07-btdf.html

I've tried manipulating the refracting angle similar to how I would a reflection angle but that doesn't seem to be working.

 

Reflection angle from 0 to 90

 

Refraction angle from 0 to 90

[symek]

If you're referring to modulating refraction angle with a texture, you probably got something wrong, it should work and produce similar results. As to ggx distribution model from above video, it's not implemented in Mantra yet. Maybe your geometry is busted?

refract_with_texture.hipnc

[jkunz07]

Thanks for the file symek,  I think the problem I was having was just the way a was wiring together the shader and combining bsdfs.  After taking another look I got it working for what I was trying to do:

 

 

Thanks!

[ssh]

Hey John,

 

That video is actually from Mantra.

 

Edit: I've updated Youtube video's description mentioning that it is Mantra.

Edited February 21, 2014 by ssh

[jkunz07]

Hey Sergey,

 

Tha's cool to hear that the video was from Mantra!

Was it using your ggx bsdf or one of Houdini's built in ones?

[ssh]

It was done in 2011 for Mantra micropoly.

Using ggx bsdf that I've implemented by myself.

 

AFAIK, Houdini does not have this model built-in at the moment.