Anisotropic Reflection (PBR)

[odcs]

Hi there,

I've got this problem with anisotropic reflection/highlights with default H11 Mantra Material render with PBR. I wonder any of you guys out there have this same problem. Please see attached image for details. Hip file attached too.

version of Houdini, Ver 11.0.504

help

pbr_anisotropic.hip

[Fabiano Berlim]

You need to change to a right 'tangent space'. Right now it's using 'Geometry Tangents', that i think is 's' and 't'.

To make it work correctly in that shape, you should use the UV space.

First you need assign a UV in the geo.

Then you should change the 'Tangent Style' in /shop/mantrasurface/sufaceModel.

Check if another 'Tangent Style' works for your needs. So you don't need to unwrap the model.

Cheers

Edited September 17, 2010 by Fabiano Berlim

[Mario Marengo]

It has to do with the tangent vectors used for the specular anisotropy.

It looks like they forgot to promote the "Tangent Style" parameter of the "surfaceModel" VOP, so it doesn't show up in the MantraSurface material.

To get to it you have to dive down into the VOP level where you'll find it in the surfaceModel VOP.

Setting the Tangent Style parameter to "Intrinsic Object Space" will give you this image:

... which may or may not be the tangent space you want (and is a useless choice if the object is animating in SOPs). You can also try the "Compute From UV" setting, but it's bound to have discontinuities for a box like yours. Plus, there are some other issues with going with the "UV" route that aren't necessarily related to your texture coordinates per se. Long story short: there are many issues with tangent space that I'm in the middle of bringing to RFE Land...

Good luck.

pbr_anisotropic_mgm.hip

EDIT: ooops... Fabiano beat me to it

[Fabiano Berlim]

EDIT: ooops... Fabiano beat me to it

Hhauhauha!!! Nobody beats you! Your contribution is always better!

Thanks for all the help you've been doing to us.

It's amazing how guys like you, Peter Claes and others, that is always working, still have time to help us.

Thank you, thank you! Keep the good work!

[odcs]

thanks guys for prompt reply guys, it works.

really greatful there r helpful people like all of you around