fg and animation

[otemato]

hello,
how can I run an fg map calculation every nth frame without render the whole sequence (like vray or turtle) inside 3ds ?
can we calculate an fg map per object ?
is there a good trick to render an animation with fg (only camera moves) without any flickering ?
the freeze option doesn't exist for max ...

thanks

[otemato]

ok i have found something :
run a render sequence of the animation (but every 10 frames or more) and with fg map rebuild. (no AA, small res for a fast render)
at final you have an fg map for your animation : render the animation at full res with fg map reuse. but there is no freeze or deep freeze option for max ,so during the rendering max will calculate the fg points (the red ones) and add them to the fg map even if you don't check rebuild.

but the question is :
is it the same as calculate an fg map every 10 frames and then merge all the maps with fg_copy ?

[bart]

You also get red points because you made the maps at lower res and you render at higher res.

Recently, some folks have used opposing methods to lower red points, eg.,
make maps at higher res and render at lower res, or
make maps with smaller FG max radius, and render back with original FG radius
make maps with increased FG presample density (not sure if this is in the max UI, so standalone might be required)

Regarding the fg_copy question, if you render with FG rebuild off (meaning append to FG map file), this would be the same as combining FG files with fg_copy. Rebuild on would rebuild the map file every 10 frames. Then, you would need to use fg_copy. However, it has a nice feature where you can set the merge radius.

[MegaPixel]

Backburner apparently doesn't know how to share the .pmap and .fgmap files for network animation rendering. So does this mean, that If send the project anyway, that each pc on the farm that receives the job, will build their own .pmaps/.fgmaps on the first frame and go on reusing them for each frame thereafter? How does this affect the overall look of the movie - flicker/grain wise?

What is the best method for using Final Gather if only the Camera will be moving (Like Architectural Interior Walkthroughs)?

[bart]

For walkthroughs, use an FG map only mode to create a single combined map, and then render with it. In 3ds max, it sounds like the freeze option is not available, which is what I would recommend for rendering. (I'm going to double check it on my version). So, you are stuck with using rebuild off for the render, or using standalone. If you create a large, dense FG map, rebuild off might still work for you.

To create the single combined FG map, keep appending FG points to the FG map (FG rebuild off), from a variety of representative camera angles.

You could also make several FG maps, and then use fg_copy to combine them with a merge offset to prevent it from getting larger than needed. Then, your original FG maps could be set up to have more density.

[otemato]

I did another test :

to calculate fg map : rebuild of, reuse fg map (the one calculated for the first frame), every 5 frames , same res as final render , sampling very low (to speed up, because in max you don't have the render only fg map option)

to render the sequence : rebuild of, reuse fg map

I have less flickering, I think I am going to increase fg sample.

Thank you Bart, for the next test I am going to make fg map at higher res and render at lower res.

With 3dsmax do we have mr standalone ? because I don't find it on max cd.

[bart]

You have to order mr standalone separately from Autodesk/Discreet. Same sales representative who sold you 3ds max should know about it.