Vray shader workflow tips in maya

[Bertjenkins]

Hi

As I'm coming to vray from mental ray in maya, i've been looking at a lot of tutorials for vray, most of which are made in max. It seems that when working on architectural renders there are general shader workflows in max which i'm finding really clunky to translate into maya. I'm wondering if anyone knows of any resources (or has any tips) which will address any of these?

1. There are many max tutorials for creating distressed/dirty surfaces (eg concrete) using multiple instances of vray dirt in clever ways. In maya i'm having trouble setting up a procedural shader which lets me adjust levels, multiply/screen composites (the equivalent of vray comptex i think?) and basically tweak the dirt procedurally without having to go back to photoshop whilst getting the look right. Wonder if anyone had any example shader networks to get me started?

2. Again for reflection fallof... in max it seems you have specific nodes for adjusting fallof. In maya it seems the sampler info node can do the same thing... but I've always found this pretty clunky compared with some of the workflows i've seen used in max. What i'd like to do is use the same reflection map and tweak it to get the right look, adjusting the fallof/ reflection blur/ reflection strength procedurally using the same file. Can anyone point me in the right direction?

any tips on either of these would be great.

Also just general tips on the speeding up of tweaking vray shaders (eg using swatches to test the look) , etc would be great!

So far the best resource by far i've found has been aweidenhammer on youtube.

thanks in advance!

[aweidenhammer]

I'm not sure what techniques you are referring to... you'd have to be specific. But the layer shader in Maya allows for doing some more advanced compositing of signals/maps. You can do mult/screen, etc. with it. Probably the equiv of compTex.

As for reflections, Maya folks are pretty used to using samplerInfo plugged into a ramp to control a fake falloff. Perhaps I'm not understanding the question properly, but you can plug the output of your falloff ramp into as many material inputs as you like, so when you adjust it, all inputs are fed the same data. As for real-time visualization of those changes, maya viewports have long sucked for this, but VrayRT helps solve this.

(btw thanks for mentioning my vids

Andrew

[Bertjenkins]

Hi Andrew

Thanks so much for your time... much appreciated!

Actually i'm a maya guy, so I haven't a clue what the compTex does (!) - but i've spent a lot of time looking through some great architectural tutorials (eg Ronen bekerman's blog) which have lots of shading networks which make a lot of sense, but are max based. I guess i was wondering if anyone had done this sort of thing in Maya...eg had any useful screen shots of their shading networks as inspiration!

I've ben trying to set up architectural shaders that are editable using levels adjust and ramps so that they are procedural, and you can just import the shader based on a psd network and discard the bits you don't need. Here's an example for falloff.



I was having trouble with the sampler info node as i was using it for reflection glossiness, until i realised reflection glossiness in the vray material only needs one value (ie from out alpha) rather than the rgb that i was plugging into it. So the reason that it was clunky is that i was using it incorrectly!

I still don't quite understand the difference between the vray fresnel shader and the sampler info node. Also I can't understand why a lot of times my renders look better when i turn 'use fresnel' off in the vray material? I guess it's because I'm controlling the fresnel manually?

Also i was unaware that you can scale up the swatches in maya much more now (2012) but i still haven't found a really nice quick way of testing out the results of these tweaks (bump, reflection falloff, reflection blur) with super fast results....

Anyway sorry for the general vagueness I guess i'm in a rush to learn!!! Thanks again for your great tutorials, I shall be keeping an eye out for the next one!

[wim.mutsaers]

I advise you to buy advanced shading course from escape studios, it's mental ray but you will learn what's fresnel, about reflections and materials stuff.

The fresnel in the vraymtl will work based on the IOR value like real world materials. The sampler_info trick will let you control in a more pratical way ajusting the ramp.

[aweidenhammer]

While I don't have time to post shader trees from Maya, I can simply give what tips I can...

Regarding turning off fresnel... yes, you should turn that off if you are piping your own ramp into reflection attributes. Otherwise, I'm not sure what you'd get.

As for speedy testing... again, that is what vrayRT is great at. Have RT running as you tweak shader settings, make and destroy connections. It isn't always stable, nor is it flawless in updating every obscure connection you can make... but for the most part, it's pure fun to see in-context results of your shader tweaks. I can't think of a more accurate and interactive way to do it.

Andrew

[t.petrov]

Hi,

It isn't always stable, nor is it flawless in updating every obscure connection you can make...

Do you have some scenes and/or description of the steps needed to reproduce these problems?
Have you reported all/some of these problems before? If not will you be kind enough to do it so, so we can try to fix them?

/Teodor

[aweidenhammer]

I'll take a look. When I was working on my last SSS tutorial, I ran into situations that wouldn't start RT (scene empty errors) and some domelight issues not updating. I'm not on a nightly at this point though. Just on the vray 2 main release... so that may be part of it.