Irradiance Caching in H10

[bhaveshpandey]

Hi, I have been workin on few simulations..

I wanted to get an Ambient Occlusion pass done..So I did the usual set up..here are my settings:

SamplinG: 256

Ray bias: 0.04

Max intr: 1e+007

Sampling angle: 90

Also I have a env map to it.

Issue is when I render out a sequence theres hell lotta flickering in it.

I even tried with the Pixel Sampling of 12 and its still there..

I am also using a spot light so I changed its shadow to Raytrace from Depth map.

Still its persisting.

I came across a thread here which mentioned that Irradiance caching was the answer..So I started looking for it

but i cant really see it....Mantra Node has an option for Irradiance Caching but where no place to specify where i could save it and some other settings like Max GI Bounces, Default Samples, Read/write mode??

(I downloaded the hip file by Rob, and it has those params...So I guess it must have been moved somewhere else in H10??)

here is the link to that thread:

link to Rob's solution

So could some one push me into the right direction?

Edited August 15, 2009 by bhaveshpandey

[symek]

Hi, I have been workin on few simulations..

I wanted to get an Ambient Occlusion pass done..So I did the usual set up..here are my settings:

SamplinG: 256

Ray bias: 0.04

Max intr: 1e+007

Sampling angle: 90

Also I have a env map to it.

Issue is when I render out a sequence theres hell lotta flickering in it.

I even tried with the Pixel Sampling of 12 and its still there..

I am also using a spot light so I changed its shadow to Raytrace from Depth map.

Still its persisting.

I came across a thread here which mentioned that Irradiance caching was the answer..So I started looking for it

but i cant really see it....Mantra Node has an option for Irradiance Caching but where no place to specify where i could save it and some other settings like Max GI Bounces, Default Samples, Read/write mode??

(I downloaded the hip file by Rob, and it has those params...So I guess it must have been moved somewhere else in H10??)

here is the link to that thread:

link to Rob's solution

So could some one push me into the right direction?

Additional options for Irradiance Cache are not installed on Mantra ROP by default. You can add them with Gear Icon on a top of Paramater's Pane of Mantra. Write in filter param "irrad" for example and here you have missing params. Note that these things can be applied on per object basis, so your static object can use different cache file (possible computed in a single frame) then deformed one.

hth.

skk.

[bhaveshpandey]

I'll be Damned! Thnaks SYmek..

However I'm facing sort of a wierd issue.

I have flickering noise creeping in my Ambient Occlusion pass....what I find weird is even if I render the same frame (for instance Frame 8) twice..I have flickering noise even in the same frame..

(its pretty odd for me..but probably someone can identify its cause and solution pretty quick)

Probably thats why Caching the Irradiance is required so that it does not flicker like mads (i guess..??)

I have included these two pictures for illustrating the same.

Let me see if irradiance caching gets me some hope now..

Its funny..just when I start getting confident, our friend H throws up something for me to tackle.

[rob]

Hi,

please fee free to post up a scene file,

Rob

[bhaveshpandey]

hey Rob..

I noticed I have a buggy version.. (295) wherein my file saves are incremental in size..

Were there any other bugs in this version??

anyways here's the hip file..

till then i'll try out the irrad caching solution on my own..

(is it anyhow related to the geometry?)

@SYmek when you said it could be done on a per object basis..did it mean I can cache out irradiance by just editing the render parameters at Scene level or I would have to set it up using ROPs??

or i could just switch the visibilty off and render out different sets of caches? and if i have to do it like this how would I load up the cache at render time?

thanks

Edit: I did a quick test with caching..but its not working..(unless i screwed it up)

I have a hunch its related to the geometry?? any ideas?

tank_AO_1.rar

Edited August 15, 2009 by bhaveshpandey

[symek]

till then i'll try out the irrad caching solution on my own..

(is it anyhow related to the geometry?)

Indeed primitives in your geometry intersects at the exact position of artefacts. You should avoid intersected polygons in case of ray trace based algorithms. They don't like each over .

Things to consider (besides repairing geo):

1). Lower ray bias on GI light shader (risking self shadowing artefacts).

2). Use ray trace mantra mode (micropolygons tend to exaggerate such intersection/self shadowing issues)

3). Render at higher shading rate.

4). I haven't checked it but you could play with Grid Edge Bias render property to decrease problems of intersecting prims.

@SYmek when you said it could be done on a per object basis..did it mean I can cache out irradiance by just editing the render parameters at Scene level

Yes, you can install irradiance related params on per object basis, what allows you control settings for every object separately.

cheers!

skk.

This was rendered in 12 sec (dualcore) after baking cache.

Edited August 16, 2009 by SYmek

[bhaveshpandey]

Hey thanks a lot SYmek....you saved me lotta time..I was trying out the PBR and in the tests so far there were no artifacts creeping out except of course the noise which i could fix by upping the Sampling..But this took good amount of time.

Thanks man

cheers,

bhavesh

[stevenong]

I noticed I have a buggy version.. (295) wherein my file saves are incremental in size..

Were there any other bugs in this version??

Yes, 10.0.295 has a bug which causes hip file sizes to increase. This thread has more information. You should download the latest H10 build which has the bug fix.

Cheers!

steven