moving snooker balls - technique

[tricky]

Not so much on moving the balls, but really how to render it.

I'm using full GI (with a pre-calc'd solution) and producing an animated camera that moves past the snooker table. I'd like to be able to move the balls around as though they have been struck.

What is the best way to do this. I expect that the balls will need to be excluded from creating GI as they are moving from frame to frame, but do they need to be excluded from receiving GI as well as the solution is 'fixed'? If that is the case, how should I actually render the balls? Ideally I need it to render as a single pass rather than comp in in post, as I need them to reflect the environment and cast shadows onto the table.

Is this possible with a saved solution, or do I need to re-calc every frame which would be time prohibitive?

[natty]

hi
you need to speek to Tom ...he is your man .... have a look at this thread http://www.chaoticdimension.com/foru...ghlight=#59006

[tricky]

Cheers Natty

I've just read through all those articles. Its darn complicated for such a semmingly simple thing! I used a similar technique with a dome of lights and a lightscape solution for an apartment animation I worked on some years ago.

I had hoped that things may have improved since then.

[tom schuelke]

Hi tricky, sure this is a tricky thing

but it has improved. it is allready much faster now, only one or two more years, and i think those tricks will be past. Hope in a few years graphic cards do the cpu job allready 50 times faster

best result still is lmap together with direct computing, but as you know this boosts rendertime. at last a good fake solution does solve the problem, and using some scripts will make your work much better.

Tom

[Da_elf]

i dont think it should take too long to render each frame using single frame GI. usually on a pool table the main light comes from overhead. if its a closeup flyby on the balls then the only real part that needs to be rendered will be the top of the table and the balls. if there is a background that can be rendered in a different pass using incremental add for GI with the table and balls hidden

[tom schuelke]

Hi Da Elf

Yes maybe you are right. the Scene where i used this fake method (you know it well ), was rather complicated, many glossys, refractions a million polygons.

yes , if his scene is that simple , he easily could do it with single frame in high settings for imap or at last in direct computation.

Geddart a month ago rendered an animaiton with an charachter with l-map and direct computation with about 3 minutes !!! a frame. so this also was always my first choise

Tom

[tricky]

Unfortunately, it is not really that simple a scene - here's a general shot:

[Da_elf]

describe the anim. where does the camera fly to and when do the balls start to animate

[tricky]

Paths haven'y yet been finalised - but there will be a couple of them. To be honest, its not just the snooker balls thing, my question relates to opening doors and moving door handles etc.

I was hoping for a simple solution

[Da_elf]

opening doors i find simple. example
frame description
0-200 moving through hall way. incremental add to current r1.vrmap
201-230 door opens (single frame)
231-330 move into new room. new incremental add to current r2.vrmap

for your pool ball simulation it might be good to render the room using incremental add to current without the balls in the scene. the balls would be animated on a seperate pass using an HDRI of your room to light them and to give reflections.