problem: vray animation rendering only pre-passes

#1

I render a lot with VRay, and I’ve done animations before in 3DS, but I guess this is my first time animating with VRay. I was surprised to find that my final .mov doesn’t have the renders - just the irradiance map pre-passes. When I rendered this scene with still images this wasn’t a problem: but now I’ve changed

  1. Irradiance Map to the “Medium - animation” preset and “Incremental add to current map”
  2. Light Cache to “Progressive path tracing” mode
  3. Render Output to “Save File”

It seems like there must be one (probable obvious) check box that I missed (not “Don’t render final image”, though - that’s unchecked). Any suggestions?
Thanks for your help,
Geoff

#2

What is moving in your scene, the camera, objects, lights changing or all together?
This decides the render method you will use.

Is it just the camera you should set:

  1. The Irradiance Map to “Multiframe Incremental”
  2. Lightcache to “Flythrough” and set both to “switch to saved map”
  3. Activate “dont render final image” and render every nth Frame, If the camera
    moves fast you will need more frames for the Incremental Map.
  4. After rendering the prepasses switch off “dont render final image”
    and hit render again for your final render pass

If you use vray sp3 you can use the camera path options to obtain results quicker
(see manual). If not only the camera is moving or changing you should use brute force methods for rendering to prevent flickering.

Hope this helps, greetz

#3

Great, thanks -

A) I had a moving camera but I also had some Blend materials to shift from transparent to opaque, so I used the brute-force QMC you suggested for primary and secondary bounces. Finally finished re-rendering and it looks good - thanks.

B) Just thought I should make sure I understand the flythrough process though. If it’s just the camera that moves, you use switch to saved map and the first time it renders multiframe incremental + flythrough, and then when those pre-passes finish it automatically switches to from file + from file so you switch don’t render final image off. The point is to save time on the pre-passes by just rendering 1 frame in every 5, 10, 30 or whatever, right?

C) If I did want to use Irradiance Map and Light Cache for an animation with moving objects (maybe to match the quality of light in a still image) I could use multiframe incremental for the IR and single frame for the LC, right? It would be inefficient time-wise though, because there’s no way to save the light cache for every nth frame and save to file, so you have to do the pre-passes at the same time which means you’re doing them for each frame. So only worth it in exceptional circumstances. Do I have that right?

Anyway, thanks a lot for your help - it fixed the movie and got my head around the process.
Geoff

#4

If you’re rendering with moving objects you first make a prepass with irradiance in animation (prepass) mode and lightcache with single frame and also check the don’t render final image. For the final pass you turn off the secondary bounces and in irradiance you change to animation (rendering), you don’t need the secondary because it’s already inside the irradiance prepass, as exaplained in the help files:
http://www.spot3d.com/vray/help/150SP1/tutorials_anim2.htm

#5

Glad that it worked for you! And yeah you get it right i think. But its not only a bit waste of time to calculate every frame with lightcache, the lightcache will differ from frame to frame and so there is a fairly high chance for flickering in your animation. This dont happen with brute force, but as you maybe allready experienced this method is very time consuming for a good quality rendering. As i allready said in the new SP3 there is a new method for calculating IRMap and lightcache called camera path, it makes the flickering problem a bit better.

happy rendering and greetz

#6

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