Mental ray AA sample, Vertical Lines, Flashing Problem

[Heisenberg27]

I'm trying render a road with white lines from an aerial camera . When I render it at 4 to 16 samples I get aa flashing on the vertical white lines. I can reduce this by increasing my sample quality to 16 by 64 but I have 5000 frames to render and this would make the animation unworkable.

 

 

I've tried reducing the spatial contrast but it has little effect.

 

 

I've considered upping the gauss filter to height 6 width 6 but this just blurs the Animation.

 

 

The question is, are their alternatives to fixing AA sampling problems in mental without resorting to super high sample per pixel rate?

 

 

I heard somewhere that maya has an option for samples per object but unsure if this exists in maxs.

 

 

 

 

Please Help

[Justin Hunt]

the shader to control AA per object does work for Max too. Iv'e not tried it though but I have read that it works well.

 

I have found that rendering to a higher resolution (up to double) with a low AA, then resampling the frames down in AE works better and quicker than super high sampling rates.

 

A bit of motion blur also helps, take a look at the HDR Motion Blur lense shader. Its a post render shader so not perfect, but still one of the fastest ways to render motion blur.

 

jhv

[Heisenberg27]

Thanks Justin

 

 

I hadn't thought of doubling the render sizes. This could be a valid work around.

 

 

I done some research on the AA per object samples plug-in. You can find it below.

http://www.maxplugins.de/mr_files/ctrl_studio/ctrl_object.zip

As far as I know this does nt ship with maxs. So for anyone needing it an install is necessary.

Instructions below.

 

 

To install

on 32 bit just copy the files into the obvious folders. the dlo goes in max>plugins.

if you're on 64-bit just rename the .x64 files (remove the .x64 bit) and use those instead of the other ones.

If you have problems installing to 2010 go to and install David Baker Mr Geometry Shader Object v1.0

You ll find it here

http://www.maxplugins.de/max2010.php?search=&sort=Author

 

 

How it works

You created a mrShader object in my scene, connected a ctrl_object shader in the slot, then dragged it in the material editor, hit add and then pick from the scene the object you want to apply the alternative sampling to.

Keep in mind, if 1 and 16 is set as your min/max AA settings in the render setup.

The only values you can now use for *object* AA are 1-1, 1-4, 4-4, 4-16 and 16-16.

In this case you would probably use 4-16 for object AA.

 

 

I've yet to try this in the scene which will need to be 1 to 64 but the plugin works in my test scene.

 

 

I post back my findings.