Pre-passes cut down from 6 to 1 - why?

[simmsimaging]

I'm just starting to use IM GI for the first time (always used BF/LC till now). I have it setup with -6/-1 min/max rates and it was rendering okay before, but I've changed some other setting I think, because every time it renders it does the LC pass, then it does only one pre-pass before starting rendering (says 1 of 1).

What other settings (render dialog, maybe materials?) could cause it to bypass the proper number of pre-passes? Is this likely to be affecting render times or quality? I can't really compare and tell now

Thanks for any tips.
/b

[leehumphries]

have you accidentally clicked the tick box for multipass under irradiance map.. to off !!

[simmsimaging]

no - that is ticked on (but more by accident than design )

Here is a screen grab of the settings in case it helps. /b

[leehumphries]

Ive looked at your settings and i can't see anything that would cause the 1 pass only.

Try resetting vray and check that the error is still there

[bardo]

did you turn ON the "distribuited render" option?? check it and disable if you don't have render slave.

[peterguthrie]

yep I reckon bardo is right, thats what I suggest checking anyway.

[simmsimaging]

did you turn ON the "distribuited render" option?? check it and disable if you don't have render slave.

Thanks guys.
DR is on for sure, but I am using 5-6 slaves. Do I have to render with IM without using DR for some reason ?

B

[peterguthrie]

When you use DR it uses bucket mode rather than the normal passes mode, makes sense if you think about it

(vray is still doing its passes, they just happen within each bucket)

[simmsimaging]

The docs suggested that single-frame mode was cool with DR, but it should be bucket mode? You are right in that it does sound sensible

I'm not even sure how much all this affects the render. Does the reduction to 1 pass reduce quality or increase render time, or neither/both?

Thanks for the help with it.
b

[peterguthrie]

The docs suggest there might be slight irr map differences at the boundaries of the buckets, but I've never had any problem with DR and irradiance map, or rather i've never noticed a difference between bucket mode and single frame mode. Where in the docs does it say single frame mode works with DR? I thought it just switches automatically to bucket mode?

[simmsimaging]

In the Spot3D docs it didn't specify, just said that incremental add mode would *not* work with DR, but when I googled it there was this from Vray.us help docs:

"Single frame - the default mode; a single irradiance map is computed for the whole image, and a new irradiance map is computed for each frame. During distributed rendering, each render server will compute its own full-image irradiance map. This is the mode to use when rendering animations of moving objects. In doing so one must make sure that the irradiance map is of sufficiently high quality to avoid flickering."

I wasn't able to find anything else that was clear or definitive so just took it that either/or would work. So you have no problems if you set it to single-frame mode?

b

[simmsimaging]

I just ran quick test and using bucket mode showed no pre-passes at all, so maybe they happen transparently when done per-bucket? The render time was about 1 min longer than the single-frame mode (which still only did 1 pre-pass) but the result looked to be almost identical.

Any further clarification available?

Thanks/b

[peterguthrie]

I think that vray.us info is from back before irradiance map calculation worked with DR.

dont know if it helps but I found this: http://www.chaosgroup.com/forums/vbu...ht=bucket+mode

[simmsimaging]

Thanks Peter, that explains it nicely.

[vlado]

I think that vray.us info is from back before irradiance map calculation worked with DR.

Keep in mind that the most up-to-date help index is the official one on http://www.spot3d.com - there are mirrors that contain outdated information.

Best regards,
Vlado