Vray & shave 7 & Render Layers Setups

[moxi]

I imagine this is a bit of a dead horse to beat but I will ask anyhow:

What are best practices when wanting to create viable setups with render layers in maya 2012 using vray 2.25 and shave 7v032.
Let's say I wanted to create the most basic setup of the following:

Situation Description: I want to composite a floating cg hairball into a practical plate that has a countertop that is reflective and over which the hairball is floating.

Render Layer Setup Desired:

(1) character beauty pass (hairball floating in air with all appropriate render elements for control, ground/set/environment primary visibility off)
(2) ground shadow pass (hairball primary visibility off, vop of ground with matte properties set to a matte surface, with an alpha contribution of -1, shadows checked, affect alpha checked)
(3) ground reflection pass (hairball primary visibility off, reflection of hairball and environment from dome light with HDR can be seen in ground which is visible and a geo plane with just an all black vray material with reflection set to .350, with fresnel, assigned. This geo plane matches the position of the countertop)
(4) character alpha for reflection pass (hairball with red surface shader or some constant shader applied to hair and geo w primary visibility off, and same ground visible which is just an all black vray material with reflection set to .350, with NO fresnel, assigned.)

I have had continuous problems with primary visibility overrides being negated on hair with shave when it came to using it with VRAY. Does anyone have any consistent workflows when applying overrides to get this simple control akin to this in Render Layers in maya...or is this just a limitation at this point with this cocktail of vray and shave?

Thanks in advance for any thoughts.

R

[Morbid Angel]

Well I have good news for you but, you must probably upgrade to newer vray build (give it a shot anyway). Essentially what you need to do is assign a vray material wrapper to the shaveDisplay node for your hair. This way you will be able to create proper matte surface control through the vray wrapper. Remember that you need to connect a constant or a material of some sort to the wrapper. The other very important factor is that you cannot assign the same wrapper (or material) to two different shaveDisplay nodes the render will be wrong (I guess not supported yet). So a single wrapper per shaveDisplay (hair node). If you wish for your beauty to use shave material, you can check override geometry shader off, in the shave hair node. And during your utility render layer override and check that on, thus prompting to use the wrapper material instead.

For the primary visibility I believe there is an option like that in the shave globals which you can use to set the hair primary visibility to off.

[moxi]

Thanks Dmitry. i have successfully rendered my aforementioned setup but with a few important caveats.

The vray wrapper is an interesting approach that i will try. I used vray object properties to accomplish most of what you are talking about because of a conflict I am finding with shave and vray together, specifically with the use of the "override geom shader" attribute.

In the latest shave 7v032 to do the primary visibility hiding that is necessary, there is a "primitives visibility" in the shave globals (As you mentioned). If you do a per layer override on the "camera" attribute under the primitives visibility in the shave globals then you will get the desired result. Using primary visibility on/off switches on anything else (i.e shave display nodes) does not work...I think Joe's creation of this global primary visibility control seems to have disabled the rest. That would be fine if I did not find that if you turn the "override geom shader" switch off (as you suggest) so you can apply alternate shaders to shave (such as the vray hair material) that it negates the primary visibility switch and always leaves it on. If you are in render layers, the hair sometimes just disappears altogether or won't render. So if I don't turn the "override geom shader" off and use the native shave shader and apply primary visibility overrides per layer through the shave globals control, it works.

I don't have access to my ftp but I can email a test scene if you want to check it out.

Does that make sense...seems like you would have run up against the problem as well since obviously you are overrideing the geom shader to use the vray hair material.

[Svetlozar Draganov]

Hello moxi

Could you please send us this scene for investigation >> vraymaya@chaosgroup.com
Thank you very much in advance.

[moxi]

Sorry I have been a bit buried. I will send the scene your way.
I will send both the test that worked with render layers without the override geom shader turned off...as well as other iterations/combinations that led to unsuccessful testing.

[moxi]

A final investigation might also be on how to best add object IDs to the hair itself for shave. Again, without turning the override shader geom option off and using vray hair mtl3. Is it not possible to do it on the shave hair or even with the native shave shader? Thanks.

[tashko.zashev]

Hi,

Please send us your test scenes to the mail that Svetlozar has posted, so we will make some further investigation about those Shave and Hair issues. If there is a bug in the V-Ray renderer we will report it to the developers.
Also don't forget to add this thread as a note. Thank you.