irradiance map for animation?

[baptiste]

hello everyone.
i'm making an animation, and i've some questions about the precalcul of irradiance map for interior scene.
i believed that when you precalc the irradiance map you should untick the light cache in the secondary bounces and put none. the mode for irradiance is mutiframe incremental or (add to current map). this is what i've done but at the render the images were very dark in comparison to still image (with single frame in both irradiance map and light cache).

so my question is: do i have to keep light cahe in 2nd bounces (with from files because it's already calculated) to calculate the irradiance map?
does the irradiance map use the light cahe to compute? (sorry for my english i hope you'll understand it)
Thank you

[baptiste]

please help me

[super gnu]

hi Baptiste. you seem to be confusing the precalc step with the rendering step. during the gi calculation, you need both lightcache and irradiance map enabled. (im assuming its a flythrough, and not animated geometry / lights? if its the latter, its a bit more complicated)

so to precalc, set the lightcache to flythrough mode, and the irradiance map to "multiframe incremental" set the irradiance map to save to a specific place, as youll need it for rendering. the lightcache is used in the calculation of the irradiance map, but unless you have "use lightcache for glossy rays" enabled, you wont need it for final rendering, so no need to save it.

then set up the frame range you want to render, and set it to render "every nth frame" in the max rendering dialogue - if your cam moves at approx walking speed in an arch. scale scene, every 20th frame should do. faster camera moves need a smaller fraqme increment.. the trick is to make sure all the geometry is covered.. i.e. there is an overlap in what you can see between frame 1 of the gi calc and frame 2 etc.

now tick "dont render final image" in the vray global switches.

now render. it will do the lightcache first, then the irradiance map for each frame in the sequence.

once it has finished, you can set secondary bounces to "none" (unless using "use lightcache for glossy rays")

and set the irradiance to "from file" and choose the file it saved.

now untick "dont render final image" set "every nth frame" to 1, choose a file path to save your frames to, and hit render.

[baptiste]

thank you Super Gnu it'is now verry clear ...