recalc final gather after changing filter?

SgWRX · April 17th, 2008

do you have to recalculate the FG solution, or if you are writing, when you change the render filter? for example from box to mitchell?

thanks

Brian Bradley · April 18th, 2008

Hi Steve,

Changing the AA filters will not make any difference
to your saved FG Map.

Regards
Bri

SgWRX · April 18th, 2008

thanks

Munz · April 19th, 2008

you can also change the Samples per Pixel and Spatial Contrast without having an effecting the Final Gather saved file.

SgWRX · April 19th, 2008

really?! a long time ago i posted something about doing FG calcs at low resolution and a small render size, like 1/4-4 at 320x240 as a memory/time saver. the response was yes, that's a good plan.

however over time, i started noticing that if i left the read/write option checked, but the freeze option un-checked, it looked like it was recalculating (much faster) based on the fact that i changed the sampling.. and on other occasions when i changed the render size.

so, i figured it made a difference. so just so i'm clear, you don't need to recalc (or, you can calculate then freeze) under these circumstances:

1. changing render output size (320x240 to 800x600)
2. sampling (1/4-4 to 16-64)
3. changing spatial contrast.
4. changing brightness/contrast in exposure control

thanks.

Brian Bradley · April 20th, 2008

Quote:

Originally Posted by SgWRX

1. changing render output size (320x240 to 800x600)

Hi Steve,

This one DOES make a difference as MR uses the pixel
space to determine FG point placement. When time is
of the essence though, this 'trick' may be necessary.

Something like 800x600 to 1024x768 would not produce
any drastic change in FG solution though.

Regards
Bri

SgWRX · April 20th, 2008

Justin Hunt · April 20th, 2008

Also if you recalc with read/write on but Freeze off, mr will skip over any existing samples, thus making it apprear to calculate faster, howerver its not updating those existing samples.

jhv

April 17th, 2008	#1 (permalink)
SgWRX Senior Member Join Date: Nov 2005 Location: Green Bay, WI Posts: 192 Name: Steve Gruesen	recalc final gather after changing filter? do you have to recalculate the FG solution, or if you are writing, when you change the render filter? for example from box to mitchell? thanks

April 18th, 2008	#2 (permalink)
Brian Bradley Senior Member Join Date: Sep 2005 Location: Greater Manchester Age: 43 Posts: 422 Name: Brian Bradley	Re: recalc final gather after changing filter? Hi Steve, Changing the AA filters will not make any difference to your saved FG Map. Regards Bri __________________ 3Ds Max - Mental Ray - VRay - Brazil Training Modules www.mentalboutmax.co.uk The MBM Blog www.mentalboutmax.blogspot.com Vray Learning Resource www.vrayelite.com

April 18th, 2008	#3 (permalink)
SgWRX Senior Member Join Date: Nov 2005 Location: Green Bay, WI Posts: 192 Name: Steve Gruesen	Re: recalc final gather after changing filter? thanks

April 19th, 2008	#4 (permalink)
Munz Senior Member Join Date: Dec 2002 Location: Chicago Age: 32 Posts: 148 Name: Tom Munz	Re: recalc final gather after changing filter? you can also change the Samples per Pixel and Spatial Contrast without having an effecting the Final Gather saved file.

April 19th, 2008	#5 (permalink)
SgWRX Senior Member Join Date: Nov 2005 Location: Green Bay, WI Posts: 192 Name: Steve Gruesen	Re: recalc final gather after changing filter? really?! a long time ago i posted something about doing FG calcs at low resolution and a small render size, like 1/4-4 at 320x240 as a memory/time saver. the response was yes, that's a good plan. however over time, i started noticing that if i left the read/write option checked, but the freeze option un-checked, it looked like it was recalculating (much faster) based on the fact that i changed the sampling.. and on other occasions when i changed the render size. so, i figured it made a difference. so just so i'm clear, you don't need to recalc (or, you can calculate then freeze) under these circumstances: 1. changing render output size (320x240 to 800x600) 2. sampling (1/4-4 to 16-64) 3. changing spatial contrast. 4. changing brightness/contrast in exposure control thanks.

April 20th, 2008	#7 (permalink)
SgWRX Senior Member Join Date: Nov 2005 Location: Green Bay, WI Posts: 192 Name: Steve Gruesen	Re: recalc final gather after changing filter? ok.

April 20th, 2008	#8 (permalink)
Justin Hunt Veteran Member Join Date: Jan 2005 Location: Brisbane Age: 33 Posts: 1,360 Name: Justin Hunt	Re: recalc final gather after changing filter? Also if you recalc with read/write on but Freeze off, mr will skip over any existing samples, thus making it apprear to calculate faster, howerver its not updating those existing samples. jhv

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