Irradiance Map too large?

[denham]

I've precalculated the irradiance map for an animation it is 166 mb.

Could the size of the IR map be significantly slowing down the rendering?

The computer I'm using should be adequate.

Our animation is 720x480 and 7000 frames. I'm getting stuck as our rendering is taking longer using the precalc method, than If I was to render the animation frame by frame from scratch. It's not a network issue, as I've copied all files to my local machine & rendered.

 

Any Ideas?

 

Thanks.

[Devin Johnston]

That doesen't seem to large for an animation that long. How much longer is the animation taking, and what are you comparing render times against?

[denham]

Actually I think I figured it out: I believe I had too much spacing on the nth frame for the irradiance, I had every 20 frames. I didn't realize that it treats this gap as brute force. I think this is why it is taking so long to render. I'm re-rendering the irradiance map for every 5th frame now. Does this sound like that could have been the problem?

 

Thanks for the repsonses

[Devin Johnston]

I'm not sure if Vray would calculate additional GI in that case but that could be the problem. How much longer was it taking?

[STRAT]

what res size it the IR map?

[hughie]

I had every 20 frames. I didn't realize that it treats this gap as brute force. I think this is why it is taking so long to render. I'm re-rendering the irradiance map for every 5th frame now. Does this sound like that could have been the problem?

 

As I understand it, if you do if for every 5th frame it will take even longer because you are creating a larger IR file.

Vray calculates the IR, say for every 10th frame and then uses that IR to render the next 10 frames. rather than the brute force you are suggesting.

So if you have a slow moving camera you can get away with longer intervals between the IR frames, if however the camera turns a corner suddenly then the IR will not be calculated for that part of the model and you will get a blotchy result.

Is any way you can break you scene into smaller chunks?

Also something I have used to get around rendering crashes because of lack of memory, is to calculate the IR at half rendering size. This should free up memory to help, without a radical loss of quality.

[denham]

I was rendering the LC & IR at 360x240, & the final animation output is going to be 720x480. The 720x480 rendering everything from scratch (LC & IR) was taking 12 minutes a frame, but when I tried the precalc method (after the IR & LC had been precalculated) the final rendering was taking 1 hour a frame? Why woudl the pre-calc take longer? My frame range was also to large (my camera was moving way to slow) I followed Ted Boardman's example of 1" of movement to 1 frame.

http://www.cgarchitect.com/upclose/article7_TB.asp

 

Based on this post: http://www.chaosgroup.com/forums/vbulletin/showthread.php?t=40729&highlight=animation

I assumed that the gap in between this 20 frames was using essentially a brute force.

 

I've also change the Adamptive DMC sampler to 1/8 instead of 1/12 to speed it up a bit.

 

I've now reduced the animation to 2600 frames instead of 7000. This should make the IR map much smaller, especially while halfing the resolution.

 

Is it OK to half the LC too? I'm using the Primary & Secondary GI for Light Cache Pre-cal.

[IgorBGD]

Why don't you chunk the animation in smaller parts, something like 500 frames? Halfing the resolution for Irr map and LC with smaller animation segments can be the way to go!

[denham]

I don't know what was happening, but my frames are rendering in 20 minutes now. The IR map is still 300 megs. If you chunk the animation, won't the beginning & ending "chunk" frames look different, and not interpolate correctly; since the IR map is an approximation.

[Mechadus]

I think Igor was suggesting you use more than 1 camera.... 7000 frames for a single camera is HUGE... thats 233 seconds of a single animation! I really try everything I can to avoid cameras having more than 1500 frames, mostly to keep the animation interesting. Only having to deal with a few cameras at 500-1000 frames tends to generate more manageable IR and LC maps too.

 

Cinematography and all that jazz.

 

Bop!... Beop.. bip bop skibble...Blort!

*jazz hands*

 

-Nick