snell's window dont work correct in houdini

[LeoYfver]

Hey!

working on an underwater shot and need to get the right reflection and refraction aka snell's window.
In maya it works correct if i have 1.3 in refraction and look from behind the object. In houdini the object doesn't show at all from the opposite side of the object and when i reverse the normal and have ior on ~0.74 and i get weird and incorrect results.
Is this something that can be lookded at pretty fast?

Regards Alexis

[Gosho.Genchev]

Hey,

assuming you're using the standard V-Ray material in Maya, dropping a V-Ray Single VOP and setting the Mode to Single-sided, with enabled Allow Negative Colors should give you the exact same setup. If that doesn't help, a Maya scene with the material only will allow us to check the difference quickly.

// as a side note - just noticed V-Ray is doing wrong things in Houdini with refraction and IPR - could you please check if a production render looks correct ?

[LeoYfver]

ok, it seems to work even without the single sided material. but it doesnt work in IPR thats why it didnt show up for me.

[Gosho.Genchev]

Yeah, that's quite the surprise for me too - I hope it's a silly bug that will be fixed quickly. Apologies for the inconvenience.

[LeoYfver]

hope so too, thanks for the help!

[Gosho.Genchev]

It must be something specific in the way the geometry in front of the camera is set up that is breaking the IPR. You could try rebuilding - it seems to me the Uniform Scale on the Geometry node is breaking things if it's parented under the camera node.

Hope that helps!

[LeoYfver]

its a consistent error even if i do a new scene. add a simple houdini and maya scene.

https://drive.google.com/open?id=1T9IBX-lb218JnweIyPD3qWL7esD8cfAcMdHRZtsBZS0