Rendering a flicker free walk-through animation

[sharktacos]

There's a tutorial for Max that goes over pre-rendering out the irradiance in order to get flicker free animation for static objects. The tutorial is here

I wanted to clarify a few things:

1) The tutorial states "Note that the irradiance map cannot be calculated through backburner. It must be calculated on a single machine. This is because we will use the Multiframe incremental Mode for the irradiance map." However this one says instead "The animation prepass can be rendered via backburner, previous methods have required you to render locally, putting your desktop out of action whilst it renders. If you do have access to another PC, I recommend using it to render the prepass, note that when rendering the preview window will not display a final result." Since these both refer to Max, I wanted to know if the irrandiance map can be calculated in Maya on a render farm, or if it needs to be done on a single machine?

2) The tutorial states "you can render different sections on different nodes, but you must merge the resulting irradiance maps manually with the irradiance map viewer in the end, before rendering the final animation. Also, you must make sure that each section is allocated to one single render node only" is this still the case for Maya using a farm? If it is instead rendered on a single machine does it not need to be combined?

3) The other tutorial says "In the irradiance map parameters, you will notice that interp. frames is not greyed out anymore. This setting determines the amount of frames that are to be blurred. The animation range is –2 to 102, so 2 would be correct. If you wish to blend 4 frames then set this to 4 but remember that you will be increasing the render times." This is not mentioned in the vray tutorial. Is is a preroll needed for Maya, and would this same advice apply?

thanks!

[sharktacos]

Also, the tutorial recommends using "multiframe incremental" but there is also now "animation (prepass)" mode. Not sure if that has been added since the tutorial was written?

Animation (prepass) - in this mode V-Ray calculates irradiance maps to be used later on for final rendering with the Animation (rendering) mode. One irradiance map is created for each frame and written into a separate file. Note that in this mode you have to render one map for each frame (i.e. you cannot render every Nth frame). V-Ray automatically disables rendering of the final image in this mode - only irradiance map prepasses are calculated.

Since the "walk-through" method described in the vray tutorial involves doing a prepass too, but involves rendering it out either a single frame or say every 10th frame as opposed to rendering every frame, what would be the reason for using the Animation (prepass) instead?

[tashko.zashev]

Hi,

Choosing the correct GI method depends on the project and the time available. There are many GI combinations that could be used to get flicker free animation.
Basically the Animation prepass mode creates .Vrmap file for each frame, which will produce better result when have moving objects. (can be calculated via backburner)
For fly-trough animations where only camera moves "Multiframe incremental", "Incremental add to current map" or "Use camera Path" option could be used.

Since the "walk-through" method described in the vray tutorial involves doing a prepass too, but involves rendering it out either a single frame or say every 10th frame as opposed to rendering every frame, what would be the reason for using the Animation (prepass) instead?

For fly-through animations you don't need to calculate every frame, its more time efficient.

1) The tutorial states "Note that the irradiance map cannot be calculated through backburner. It must be calculated on a single machine. This is because we will use the Multiframe incremental Mode for the irradiance map." However this one says instead "The animation prepass can be rendered via backburner, previous methods have required you to render locally, putting your desktop out of action whilst it renders. If you do have access to another PC, I recommend using it to render the prepass, note that when rendering the preview window will not display a final result." Since these both refer to Max, I wanted to know if the irrandiance map can be calculated in Maya on a render farm, or if it needs to be done on a single machine?

Irradiance map modes and all animation workflows are applied to both, 3DS Max and Maya. Animation prepass calculation could be calculated on several machines, while the Multiframe one should be calculated locally.

2) The tutorial states "you can render different sections on different nodes, but you must merge the resulting irradiance maps manually with the irradiance map viewer in the end, before rendering the final animation. Also, you must make sure that each section is allocated to one single render node only" is this still the case for Maya using a farm? If it is instead rendered on a single machine does it not need to be combined?

Yes, it's possible to precalculate the Irr map on all render nodes (Multirfame mode), when the animation sequence is divided on two or more parts (depending on the number of the slaves) . Then merge them with Irradiance map viewer.
If you do it on the single (local) machine, the result will be only one .Vrmap file.

3) The other tutorial says "In the irradiance map parameters, you will notice that interp. frames is not greyed out anymore. This setting determines the amount of frames that are to be blurred. The animation range is –2 to 102, so 2 would be correct. If you wish to blend 4 frames then set this to 4 but remember that you will be increasing the render times." This is not mentioned in the vray tutorial. Is is a preroll needed for Maya, and would this same advice apply?

This option (Interp. Frames) is always active in V-Ray for Maya, but it is only taken into account when Irr Mode is set to Animation rendering.
From our help spot:
"Interp. frames - this determines the number of frames that will be used to interpolate GI when the Mode is set to Animation (rendering). In this mode, V-Ray interpolates the irradiance from the maps of several adjacent frames to help smooth out any flickering. Note that the actual number of frames used is 2*(interp. frames)+1 - e.g. the default value of 2 means that in total 5 irradiance maps will be interpolated. Higher values slow down the rendering and may produce "lagging" effect. Lower values render faster but may increase flickering."