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Issue with final gather map


JamesDeacon
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I'm trying to create a basic animation of a building that I've modeled, but I'm having a few problems with the final gather solution.

 

With Read/Write file enabled and as the animation progresses artifacts begin to appear and continually get worse. The first frame looks fine, but by the final frame the animation looks terrible. Strangely, if I render the final frame without Read/Write file enabled, the result is good.

 

I was hoping to create a final gather map and then freeze it before rendering the final animation to avoid flickering and improve the render time (I don't have a very power full machine for rendering, just a laptop).

 

I have included some images below so you can see for yourself. The first image is the 1st frame of the animation. The 2nd image is the final frame of the animation with read/write file enable (the one with the artifacts). And the final image is the last frame of the animation rendered with read/write file disabled.

 

The scene is simply lit by a MR sun and MR sky with logarithmic exposure control enabled.

 

The final gather settings are as follows

FG Point density 3.0

Rays per FG point 1400

Interpolate over number of FG points 6 (I know this is pretty low, but if I have it any higher the weather boards start to look flat)

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what version of max are you using? if it's 2010 or higher have you tried the "FG points along camera path" option?

 

those artifacts look like interpolation errors as well ass image sampling.

 

In gerneral you fg settings are very high indeed, animations can get away with much lower settings, which will help with render times and momory issues.

 

jhv

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I'm using 3ds Max 9. I realize the FG settings are kinda high, but if I use lower values a lot of the models detail gets lost. Surprisingly the fg only takes maybe 7minutes to calculate for the first frame, and each successive frame is faster (that's with read/write file enabled of course) so it's really not that slow.

 

Whats the architecture industry like in Brisbane right now? I'm an architecture grad trying to find a job, but I'm not having much luck over here in NZ.

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[ATTACH=CONFIG]41116[/ATTACH][ATTACH=CONFIG]41117[/ATTACH][ATTACH=CONFIG]41118[/ATTACH]Thanks for the model, and a very nice model indeed.

I have played with it a bit to see whats going on. Bear in mind that I am using Max2011 so things have changed since Max9 days.

 

I was able to recreate your issue, I still think its the interpolation causing problems.

I made a few tweaks which seemed to help.

 

FG settings:

Density 0.5

FG Points 500

Interpolation 80

Diffuse bounces 1

Generated FG for every tenth fram

 

Materials

Now I cant remeamber if Max9 has the Arch&Design material, if it does use it

I changed the material to an A&D, with the Matte preset

Diffuse colour 0.7

AO with a 1.5m radius and a mid grey for the shadow colour. This will bring back the detail

 

AA 4, 16 with spacial contrast 0.3

 

Now alot of the AA issues will be helped/ solved when final materials are applied. Mainly in the Window frames.

 

Just for fun I also did a test using Photons and FG. I feel this gave the most detailed lighting.

 

Photon Settings

Max no Photons per Sample 50

Max Sampling Radius 0.3m

Optimize for FG ON

GI Photons 10 000000

Trace Depth Max500 , reflections 250 and Refractions 250

 

FG Settings

Same as before except Difuse bounces @ 0

 

I am rendering off the animation with each of the settings and will upload them when they are done

 

HTH

 

JHV

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You are a legend, thanks so much. Max 9 does have Arch & Design materials and the AO worked a treat. I did a few tests this afternoon and got some nice results. It's also good to be able to understand how my approach was wrong. I'll install the 2011 trial tomorrow (as long as my bandwidth allows) and have a look at your set ups. I'd heard of AO in the past, but never really understood what it was for until now. I will let you know when the finished product is uploaded to my portfolios you can check it out if you like?

 

Thanks again,

 

James

Edited by JamesDeacon
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