Saved irradiance maps taking longer

[grasshopper]

Hi Folks, I am trying to render my first animation using VRay and having a bit of a problem with my irradiance maps. I have a 1500 frame fly thru with only the camera moving and what I did was rendered the irradiance map in 100 frame sections to different machines and stuck them together using irradiance map viewer to compile one 250Mb irradiance map.

Now all seem fine until I try and render the final image which is now taking 30 mins plus to render a frame. This is strange because if I render without the saved map it only takes about 14 mins.

I have played around with Anti aliasing settings and QMC samples but don't seem to get much improvement.

Is there an issue when using large irradiance maps. As they have more information in them could they take longer to render. I’m i bit baffled or could i have screwed them up with IR map viewer. I'm going to start calculating an other IR map on one PC over the weekend unless i can solve today.

Any advise or guidance would be appreciated to save me having to start over or make the same mistakes again. Cheers

[vlado]

What are you irradiance map settings?

Best regards,
Vlado

[grasshopper]

Min -2
Max-1

Clr Thresh - 0.4
Nrm Thresh -0.3
Dist thresh - 0.1
Blur - 0.0

HSph - 50
Interp - 20

Interpolation - Least Squares Fit
Sample Lookup - Overlapping

Question - If your using an irradiance map from a file do these settings affect the final render?

Cheers

[vlado]

You can try changing the Sample lookup method to the default (Density based) and see if this helps.

Best regards,
Vlado

[grasshopper]

Thanks I'll give it a go.

Mean time i have gone back and done some tests.

If i create a new IR map for the first frame only and use that to render the first frame i takes about 2 mins but if i use the IR map from the whole anim and render the first frame it takes 30min. HOW COME????

[vlado]

The irradiance map for the entire animation has a lot more samples than the irradiance map for a single frame. Further on, with the Overlapping look-up, it may become unnecesarily slow.

Best regards,
Vlado

[grasshopper]

But surley that makes pre rendering irradiance maps for an animation useless for anything other that a very short animation.

Actually when creating my IR map i rendered every frame would rendering every 5 or 10 frames maybe give me a quicker render time?

[Clifton Santiago]

Try only rendering every 10th frame for the IR map. Check Multiframe incremental and render on only one machine.

I don't know if the IR map will be any smaller, but you won't have to merge a bunch together. It always works for me.

[grasshopper]

I'll try that over the weekend and let you know the results.

Thanks for your help

[nlo]

i had the same problem with 1.47.03...

i rendered multiframe incremental every 20th frame on one machine
resulting in a 140mb irrmap file.

now rendering a single frame on my renderslaves took longer than directly creating irr map+rendering every frame!

i tried dyn memory (different sizes 600-2000 - no effect) and different irr map lookup types (density based, overlapping - did not make a difference).

on my strongest machine (xp64, 4gb) i worked good and fast when set to
static memory (3-10min/frame), irr map was loaded once.

on my slaves (win32, 2gb) it crashed with static memory and rendered slow with dyn memory (40-100min/frame), irr was loaded for every frame.

i did not really solve the problem, but i was able to render the longest scene on my xp64 computer in time. the shorter scenes had smaller irr maps (70mb) and with dyn memory they worked on my slaves - not fast but okay and without crashing.