Has anyone used Vray in an ambient occlusion pipline?
Ambient occlusion in Vray would be sweet! But its not possible as far as I know at least compared to other renderers.
Since ambient occlusion is just another name for “skylight”, you can do that with VRay; however if you want more information (like average unoccluded direction) you’d need to write your own material with the VRay shading SDK…
Best regards,
Vlado
Is the average unoccluded direction the same thing as the ‘bent normal’ maps you read about in renderman books?
Creating Ambient Occlusion in vray is a no brainer.
Make all your materials Vraymat and diffuse of white.
Turn on GI and make secondary bounces none.
Turn your environment override on and turn your color to white.
you are done.
Hit render and make anyone that has ever done in in renderman really pissed off.
Ambient Occlusion is fancy word for a single bounce enviroment GI. No one inmy book doe AO faster then Vray and yet it is the simplest thing that it does.
yeah. when i bought my after effects in production book they had a video on there where they mentioned ambient oclusion. however they were setting it up using raytrace. but as cpnichols mentions its as simple as what he discribed
Yeah, thats how I have been doing it. I was wondering if it was that simple or if there were any tricks to it.
cpnichols: Why did you specify Vraymat material? I have been using standard materials and havent had any problems.
Jordan: the VRay material is a little faster than the standard one.
my assumption of ambient occlusion was that using it allowed you to create certain effects (skylight) or reflection without actually using intensive raytracing. For reflection, an occlusion map would allow you to set an object to use a reflection map and have more natural reflections since your enviroment map wouldn’t show up when a portion of the model would inner reflect.
It would be great if someone would take the time to write a ambient occlusion shader for vray. ambient occlusion has been used in many professional movies at the time allso.
No real reason for a shader IMHO, just make a simple white vraymtl and use GI with white skylight and 1 bounce (turn secondaries off). most scenes will render quickly even at high animation settings. I think a material is handy only in renderers where GI is very slow or missing.
agreed. you only hear about ambient occlusion being used WITH slow GI renderers.
percy
well i think ambient occlusion is better if it is like a map. that way we can create some dirty/stressed surfaces.. or we will be able to mask reflections or create some other effects like landscape shader.
i really dont think it is a better way to fake GI.
the potential usage can be under material as a masking tool.
OK if I understand what it is, using ambient occlusion means faking a GI solution and use it like a mask in post production right? So you guys think this is useful in vray? I mean, I guess it can be useful sometimes to have a global illumination calculated on a specific layer, but it’s not like vray ‘s GI is that slow… and taboo seems to talk about something that is still unclear to me, the cavity mapping if I remember well, and “landscape shading”, and such… are those like fake displacement maps or somethin’?
it might not be so usefull for stills where you can hapily spend 10min+ on each frame, but in an animation house where speed and flexability is a must AO is great. It is quite cheep and allows a lot of flexability in post so the right balance of skylight and key light is achieved. It saves a lot of rerendering and adds a nice touch to the final look.
But is it suppose to replace GI to save rendering time or to “add a nice touch” to the rendering?
Personally i think the strong point to the ambient occlusion pass is in production pipelines where massive amount of post production comping is done. with an ambient occlusion pass you can have alot of flexibility in your post production package like shake, combustion, AE, DF or whatever your preference is. Now with vray1.5 comming up with the much awaited for render passes we might see that ambient occlusion isnt even needed. Who knows what is in store for us. I personally never used Ambient occlusion but i could see its uses when using slow GI solutions.
To answer suitaloon’s question it is a replacement, true it is nice to have the area light as a layer in a composite, but it is a cheap replacement of true GI. It is however very convenient to just apply a white material and send it to render for an animation.
Thank y’all for these clarifications. I now know what means ambient occlusion and I can sound clever at the office. coool
i was saying ambient occlusion under vray can be used as a map for vray material to find out objects bumps and dents. I think to use it for faking GI is pretty much useless for Vray. Since we have a extreamly fast GI renderer 
That was what i was wishing to have. i mean using ambient occlusion for finding bumps and dents of the object, to create dirt maps or masking self reflections or creating nice looking stressed metal surfaces or even creating landscape shader.
Basicly i am looking for something in Vray, like dirtmap for mentalray… because it uses ambient occlusion.