Fresnel reflection & transparency

[linuxop]

Hi. I am new to Maya, and I am wondering how I can achieve fresnel effects, such as the effect where reflection and transparency is dependent upon angle of incidence. The program I am used to working with, Cinema 4D, has precision controls for this. How do I do it in Maya? Thanks.

[joojaa]

Connect the reflectivity and transparency to the facing ratio of the sampler info node!

[linuxop]

How do I do that exactly? I created a sampleinfo node, connected it to the main texture, tied tranparency to normal camera in the connection editor. The result was a fresnel like effect, but with strange color shifting. The controls in the Sampler Info Attributes didn't seem to do anything. No luck tying transparency to facing ratio either. Read up on the connection editor, but couldn't make out what to do exactly. Fresnel effects are essential to making realistic materials, and I really want to get how to do it. Thanks.

[joojaa]

Hmm... Maya is a bit technical when it comes to shading. The bright side with this is that you can do very complex things with the renderer. unfortunately simple things get easily quite complicated.

Heres a link. Allso read the online manual on rendering connections etc. (Hit F1):

www.aliaswavefront.com -> maya community -> learning -> How tos -> rendering -> How to Create Realistic Glass.

Sometimes it doesnt work if you link directly. So that swhy i did it complicated.

[linuxop]

Thank you for your help Joojaa. I rendered this following the glass tutorial on the alias website that you suggested. I agree the method is pretty complicated for so common a task, but that Maya offers some powerful shading tools. I used raytraced shadows. One problem though. Do you have any idea about why the shadow of the far wood ball doesn't show in the refraction of the glass?

[joojaa]

Dunno? One thing that might cause ithiskind of behaivour is the recursion depth (try fidling with the reflection and refracion limits), wich might or mightnot be set too shallow (setting this as low as possible is suslly wise but id say that in your case 4-6 should be sufficent)Also if you set differing walues to the object than say in the material then the lowest possible is obeyed.

[linuxop]

Thanks again. It was the ray depth. BTW, I have a highend3d forum question. I am using IE on Mac, and every time the page loads, it seems to reload just to slightly resize things in layout. This really slows things down. Do you know of any way to stop this from happening, or improve forum speed?

[linuxop]

Here is the image again with ray depth increased to 6. I have one new problem/question (did you doubt? ) Notice the shadow edges produced by the glass? I thought this was due to the fresnel effects I had set up. But as it turns out, even if I remove all those fresnel effects, I still get this shadow attenuation at edges. That is not what I would have expected. So my question is this: Is there any way to attenuate that effect, to adjust the contrast of those edges? At one point in reading the documentation I thought I read something about this, but now I can't find anything. Thanks again for any suggestions you can give me.

[joojaa]

Yes just can remeber its name offhand (but its under the raytracing optios for your material i think, but i have a wague feeling it was named atenuation), well ill come back to you once i get to work or home so that i can chenk ithis in maya or the manual

Unless you offcourse have figured it out by then.

[skyphyr]

Guys - love your work

I'd been dumb enough to think no - it couldn't possibly be my ray depth causing the problem of shadows no showing through glass in my scene - I've got it set at 20... Then I read this while looking for answers and all of a sudden the room filled with a bright light as I woke up and realised it was only set to one on the light casting the shadows...

goofy grin so thanks for answering the question I hadn't asked

skyPhyr.