FG map for moving objects

[mdviz]

Any one got any way/methology for creating the fg map for a scene with moving camera and moving objects on 32bit 2009

 

I have been trying to pre calc the FG for a scene 2.7m polys, 450fs @720x405.

 

I have been rendering every frame for when the objects are moving but the fg map is well over 100mb for the first 249 frames where it keeps crashing. I have aa set to lowest and tried sending through backburner to keep the crash recovery going but it still is hanging after 249 frames.

 

Task manager states that max is only using 500Mb ram and the total system Ram used is 1.5Gb. I am on 32 bit XP, 3Gb ram

 

I have tried calcing every 10 fames but this results in 'flickers' where the objects are moving.

 

I know 64bit would help with memory/crashing but 32bit is what I am stuck with at the moment.

 

Any pointers appreciated

[SandmanNinja]

I think every other frame is acceptable and preferred

[Justin Hunt]

May not be the most helpful suggestion but now in Max2010 there is a to calculate fg for moving objects. Basically it saves a different fgm for every nth frame and the interpolates between them. I've not tried it but have seen some demos and looked quite promising.

 

jhv

[SandmanNinja]

That is very cool, Justin.

 

Does it somehow track the object's movement and the camera movement and then "Solves for x"?

[Justin Hunt]

from what I understand it works as such

 

Say you render every 10 frames, a new FGM will be created and saved for each of those frames. When you re-render every frame it will use the FGM for frames 1 to 9 and then interpolate frames 9 to 11 from FGM 01 and 02 and so on. (The numbers are not exact just for illustration purposes)

 

By doing this you should get flicker free lighting.

 

From the movies I saw (I think they are on the autodesk website max2010 features) they showed the FG samples sliding across surfeces using the old methode and then the FG samples not sliding and adjusting with the new methode.

 

Once again this is what I think is happening so if anyone has a more accurate discription I'd love to hear it.

 

jhv

[SandmanNinja]

And Bri rocks the Casbah (again!)

[Justin Hunt]

cool. I had a look for those videos I was talking about. They are gone. I know I downloaded them but deleted them in a bit of a clean up last week:D

 

jhv

[quizzy]

I have been doing some interior animation tests as well with MR in max2010.

I've not used max2009, but to my understanding there are some major differences, especially inside the re-using of the FG maps.

So for max2010 the following applies (based on my tests)

 

For a walkthrough camera, with no moving objects, you can use the one FG map solution. This one map fg solution is being incrementally calculated over the camera path which will give you one big-ish fg map for the entire animation. Depending on how detailed your fg map settings are the size of it can be huuuuuuuuuuuuuge.

Try to get away with less samples if this happens (could/should/is likely the thing that crashes your 32bit machine) and get more detail in with either a seperate AO pass or enabling the AO in all the materials.

 

Now for walkthroughs (or some less boring animation types) with moving objects I've calculated for every frame an fg map. Again depending on detail in the fg map, this might take a looooong while. It now creates one fg map per frame. During final rendering you can set the interpolation over N frames. If your value is for example 3, it takes 3 frames before the current frame, the current frame, and 3 frames after the current frame, so in total it interpolates between 7 fg maps.

 

The following test animation was done like this: calculate all frames's fg maps. and interpolated over 20 frames. If I should lower that value to 3 its most likely sure the animation will show more subtile changes in the GI solution, also without flickering ofcourse.

I still need to test wether it is possible in this animation to calculate every 2nd frame and then interpolate on a lesser number, lets say around 8 or 10.

 

BTW, I'm a total MR noob and am just starting to learn that thing so... I could be wrong. ;-)

 

here's the animation: http://www.3idee.nl/sf/interior.wmv

[Justin Hunt]

There are now two methodes for calculating FG for walkthroughs, The old one where you calculate every nth frame and a new one where the FG is calculated from variouse points along the animation path.

 

The new way is very quick as it does the calculations once. The frame buffer is divided up into the specified number of point along the path. This is rather good in that it is possible to see the whole path at the same time making identifying problem areas simple. Down side if you have to up the density to get good detail, and if there are areas inbetween these points you can get artifacts if samples cant be correctly interpolated.

 

I use a combination of both methodes. First I do the points along the path, then I either do specific frames or every nth frame to clean up problem areas.

 

This results in a clean, detailed FGM that isn't too big, even for very long, sweeping animations. Granted I dont worry too much about moving objects as these tend to have very little influence to the overall lighting and whatever flickering they do cause is unnoticable.

 

jhv

[quizzy]

to my understanding, depending on the mode in reuse, it reads either the one big single file, or all the seperate files, not both.

[Justin Hunt]

If you save as Incramentally Add, then both are written to the same file, therefor read from that file.

 

If you use several fgm files then yes it will only read those files so you cant use my double method.

 

jhv

[milfora]

Hi,

 

I don't know if somebody has already mentioned this, but I generally hide my animated objects before calcing the FG map (I'm using Max 2009). I render every nth frame depending on how fast/slow the camera is moving (closer intervals if the camera is moving fast).

 

I find that this removes most - if not all - of my flickering issues.

 

Regards

 

AM