Mental ray & OnyxTREE flickering

[Ardak]

First of all, I apologize if this has been discussed here before, please direct me with the right link to the existing thread if there is one. And second, sorry if this is in the wrong category.

 

But the question is, I am using mental ray and using tree models exported from OnyxTREE progam as .obj or .3ds files to my scene, whenever I render the animation, the trees flicker very annoingly. I don't have anything else flickering in the scene. I have tried to use high anti-aliasing and such, what would be the best way to correct this? Thank you.

[thorsten hartmann]

Hi

 

that is easy, you need the right AA Values. AA Setting to create Movie...

 

Samples:

min = 4, max = 64,

 

Spartial contrast:

R=0.035, G=0.035, B=0.035, A=0.035

 

Lock Samples = off

Jitter = on

Filter: Trangle or Mitchel

 

mfg

hot chip

[RevitGary]

"Samples:

min = 4, max = 64,"

 

Doesnt that increase render time a lot? Is there another way?

[Cyberstyle]

The flickering is caused by FG. Give this s try; First set your output frame range to start at -2.

Set your FG to project points along camera path and use the disk caching set to 'single file'.

Run a FG pass saving the file (incremenraly add FG to files) but use a higher quality solution at half your final resolution. (don't forget to check the 'skip final rendering' box). Then hit the 'generate final gather now button'.Once you have your FG files, set your final resolution and set the FG to 'read only' and uncheck the 'skip final rendering box'.

Set your frame output range back to start on 0 and render your frames.

[RevitGary]

The flickering is caused by FG. Give this s try; First set your output frame range to start at -2.

Set your FG to project points along camera path and use the disk caching set to 'single file'.

Run a FG pass saving the file (incremenraly add FG to files) but use a higher quality solution at half your final resolution. (don't forget to check the 'skip final rendering' box). Then hit the 'generate final gather now button'.Once you have your FG files, set your final resolution and set the FG to 'read only' and uncheck the 'skip final rendering box'.

Set your frame output range back to start on 0 and render your frames.

 

Dont you mean

 

"but use a lower quality solution at half your final resolution"

 

Also does anyone else use the -2 starting point I have never heard of this.

[Cyberstyle]

Dont you mean

 

"but use a lower quality solution at half your final resolution"

 

Also does anyone else use the -2 starting point I have never heard of this.

No I meant what I wrote - Use a higher quality FG solution at half your final resolution and save the files to reuse. That higher quality solution can be applied to a higher resolution frame with little to no loss in quality.

 

Using the -2 gives the FG a way to average the frames and calculate the solution for frame 0 if the interpolate over N frames is at the default of 2.

[sandy_maith]

Hi

 

that is easy, you need the right AA Values. AA Setting to create Movie...

 

Samples:

min = 4, max = 64,

 

Spartial contrast:

R=0.035, G=0.035, B=0.035, A=0.035

 

Lock Samples = off

Jitter = on

Filter: Trangle or Mitchel

 

mfg

hot chip

but even this is not enough when you have trees very far away from the camera....i think mental ray is not very good at handling very low spatial contrast value..i'm trying to render a vue scene inside max with a lot of trees..my fg dosesnt flicker but trees at a distance do. i know its antialiasing but dont yet know a solution.

I achieved a fairly decent result but one frame tool 2.5 hrs for a HD render.

Any further ideas on how to handle AA flickering issue?

sandy

[Justin Hunt]

I have found in cetain situations you will get better AA results if you render to a higher resolution but with lower aa settings, some thing like 1;16 or even 1;4 whilst rendering to double HD resoluion. Then down sizing in AE or Photoshop.

Have you tried the new unified sampling?

 

JHV

[sandy_maith]

i did try that and it works in some situations...i just downloaded this unified sampling (render optimizer script) from thorsten's website (a great guy indeed) and trying to understand how it works in this situation...are there any good articles available on this online you know of though i'm also looking for some..

thnks

[sandy_maith]

ok..so i checked it out ( http://www.infinity-vision.de/blog/unified_sampling ) and what i understood is

1. the value specified in minimum no of samples will always be used to plot a pixel.

2. It will use maximum samples till it properly renders a pixel (am i correct or is it controlled by quality value?)

3. If using this, it will override the mental ray sampling quality.

Pls correct me if i'm not understanding something on this.

 

So i guess the correct way of using this is to bake your fg and the use high sampling from the unified tab .....right?

 

I'm having one more issue here...while caching fg map..it always come out to be 834 kb and when i say read from the file..it ignores it and computes final gather again..!! this is strange and i'm seeing it for the first time..

I'm using max 2012 sp2

Edited April 7, 2012 by sandy_maith

[MrCAD]

try checking this link out.. might help you

http://www.jhjariwala.com/2012/01/09/its-not-fg-final-gather-flickering/

 

Meher

[sandy_maith]

Thanks meher

If u read my post carefully, there are some situations beyond this technique..you wont get good results without heavy rendering times...i think unified sampling is the way to go..i'm experimenting and getting quite acceptable results with good rendering times..if anyone has tackled AA flicker with unified sampling effectively, would love to hear from them..

cheers

sandy

[TSuess]

Thanks Thorsten. This worked for me.