IOR Bug?

[markman]

I tried to make glass material in XSI but the the refraction always came out wrong. When I use an SI 3D shader the refraction looks right. Can anyone explain what

[markman]

Can anone help me or confirm this bug? Ed? Matt? Bernard?...

Markus

[wolfinger]

what is the IOR in the XSI pic?

[markman]

The IOR is 1.333 in both pics and both pics are rendered in XSI2.01 but one is using an SI/3D shader. Refraction depth is also high enough. I also tried example scenes that ship with XSI with same result.
It looks like the rays are only refracted by the first surface and then go straight through the object.

Markus

[atyss]

Hum why don't you use the SI3D shader, if it works better than the XSI one? Is there a limitation with the SI3D shader that I'm unaware of?

Personally I wouldn't bother, because you have a way to achieve what you want (by using the SI3D shader). The point is that if something works better than another things, well that's fine, no?

Sorry I can't be more help
Salutations - Cheers
Bernard Lebel

[markman]

The problem with SI/3D shader is that you can

[richard-sher]

Try turning the ray depth up. (Both refraction and reflection)

[markman]

I did this, of course. I assume this is a bug.
Could you try it yourself? It

[atyss]

To: support@softimage.com

Bernard

[oliverj]

Hi,

sorry for my late answer but this has to do with a front/back ray switch issue in XSI shaders.

Just add a front/back switch node, and set the refraction index of the back material at 1.0.

Hope this helps.

Guy.

[pnoizat2]

thanks for the clear consise resolution.
have you seen edward tufte's book called envisioning information. (perhaps this is a random thought, but expect you will like it)

there is a little deviation at the neck. assumeing the si|3d verson is correct. any ideas?

sam

[deathrasher]

I could not agree with SMedic
The front/back switch node does not consider the camera POS and the model`s shap, if you look through the cup from top, you will find the refraction is not proper.

Front/back switch node just like dual shap way (I copy the cup,invert the normals, set IOR=1, transparency=1,simulate the air refraction face,and SET render option >optimization>face mode>front1), that`s not the perfect one !

2 years ago ,I found this bug , I sent a email to softimage, but they did not reply ,I hope they fix it soon

waterblue_xsi@163.com
waterblue_2002@yahoo.com

[oliverj]

Your normals are inverted.

Guy.