Practical solutions for rendering animation in Vray?

[3Dmotif]

Ok so most of what I have found refers to something pre and post SP2 and I assume that has something to do with 3dsmax version. IDK but here is the thing:

I have a few minute animation to render.

In all shots the only lighting is Vray sun and sky.

In about 60% of the shots the only thing that moves is the camera.

There is Water in all of the shots that consists of a plane that has an animated bump maps for altering the reflections and refractions.It is clear and under it is a Env_fog volume that simulates the objects fading into the depths.

In about 4-5 shots I have moving objects.

The only think I have found that is even close to making sense is this tutorial:

http://www.workshop.mintviz.com/tuto...on-using-vray/

But this involes for all intensive purposes rendering the scene twice. One time to render the light cache and Irradiance map, and once for the final render.

Surely there is something that can do this faster? I mean with MR I can use the FG_shooter shader and just render with not even that high of settings.It sounds like this is kinda like the use camera path option in Vray does the same thing. I just don't understand the need to go thru all of this pre-pass rendering. seems like a very antiquated workflow.

Should I just not be using Vray for rendering animation? I was under the impression that is was being heavily used in film and TV these days. But what little information I can find list methods that are just completely impractical for production. Maybe I'm just looking in the wrong places. But it seems that there are almost not tutorials that are related to rendering stills.

[Neilg]

that guide is the wrong one, you should be following one for static objects - that one is for moving objects.

First pass:
Switch off glossy effects
Switch on 'dont render final image'
(you change global reflection/refraction depth to 1 here for a faster result, but it depends how many layers of glass you're looking through in your scene)
Change ir map mode to 'multiframe incremental'
check on auto save, pick a location
change light cache to 'fly through'
pick a location for the lc file
switch off 'save file'
render the full sequence every 20 frames assigned to ONE machine .

Second pass:
Switch on glossy effects
switch off dont render final image
change ir to 'from file', pick location
same for light cache
switch on save file
render every frame

In the scenes with moving objects, hide them and render the backgrounds using this method.
For the moving objects look into using sphere fades with the method in that link. or brute force & LC in a sphere fade (probably much easier).

[3Dmotif]

render the full sequence every 20 frames assigned to ONE machine .

do you mean render every 20 frames on a machine or on a single machine only render every 20th frame?

Just checking.

[Neilg]

Arent they the same thing? i dont understand the question.

Do you have an option in maya to render to render every 20th frame?
use that, and assign it to one machine, and make sure it doesnt get interrupted. This does an IRmap, keeps it in memory (why you need it to run on one machine) and 20 frames ahead looks at what it already has and only adds IR map information where it needs to. the first frame will take 2-3x as long as all subsequent frames.

[3Dmotif]

hmm ok so then it sound like the IRmap is similar to the FGmap in MR?

[Svetlozar Draganov]

Here you could find a complete tutorials about rendering Walk-Through / Moving Object animations.

http://docs.chaosgroup.com/display/V...ough+Animation
http://docs.chaosgroup.com/display/V...Moving+Objects
http://docs.chaosgroup.com/display/V...ing+Objects+II

Prepass rendering is needed in order to generate less flickering animation. Most of the Adaptive Global Illumination solutions like IM and LC are used in a special way depending on the animation type - for example for animation where only the camera moves there is no need to calculate Global Illumination for every frame in most of the cases 1 GI solution for 50 frames is enough depending on the camera speed, this process is very fast and you could save a lot of render-time. You could run the animation directly without any pre-passes but it will cost more render-times and lower-quality animation.

You can avoid pre-passes if you are using Brute Force/Light Cache or Brute Force/Brute Force approaches. These methods are suitable for rendering animation with moving objects and they don't require pre-calculation. Of course you could also render Walk-Through animation with them but they will require a lot more time than IM+LC approach.

[kristianturner85]

Really good advice,

This is something that I'm testing in Vray 3 with progressive rendering method. When using Brute-force and rendering for a pre-vis or proxy, you can set a time limit per frame so you know you will definitely have something in whatever deadline you are working to, say you need to render overnight. For camera fly-throughs IM-LC is definitely the most efficient way of rendering but with other animated elements Brute-force is beginning to be a real option.

There is a new way of using the two methods in conjunction which is very interesting. There is a new option is the object properties to use Irradiance Map, this means you can pre-calculate the non animated elements in your scene and then when rendering the final image, use brute force and for this the GI will only be re-calculated on objects which are not associated with the VrayObjectProperties. I haven't fully tested this but in a presentation it seemed to work well.

food for thought.

-K

[3Dmotif]

pick a location for the lc file
switch off 'save file'

Turn off save? this disabled where you just picked to output the file.

[Neilg]

render output save file.

[3Dmotif]

render output save file.

ok but you tell me to tell it where to save the LC file then right after you tell me not to turn off save is that correct?

[Neilg]

no, you're confused. they're not part of the same thing.
the dialog where you choose to save the actual rendering is called 'save file', you switch this off. you should still save the LC. i'm talking about not saving the image in the frame buffer.