View Full Version : Radiosity Cache

05-08-2012, 08:58 AM
With cache checked (but not animated cache) does the cache file change during multiple frame rendering? I was hoping it didn't, but it seems that it does.

I'm guessing now that in order to maintain the cache file without changing, you'd have to render most or all frames in the scene. Is this correct?

05-08-2012, 09:08 AM
Caching in Lightwave is great! We use Interpolated Radiosity on most everything, it gives us a nice splash of color from surrounding objects and fills in the harsh shadows with bounced light without taking forever. There are a couple of things to know.

1. When you cache a scene, make sure you have the "Automatic" option selected under preprocess. This will allow subsequent frames that are calculated to aqcuire their information from previously calculated frames.

2. We typically set the frame step to about 20-50 depending on how fast we are moving through a scene. What you need to remember is once Lightwave has SEEN the geomeotry in the scene (through the camera) and baked that part, you don't need to bake that area again (unless you get closer, see it at a different angle etc).

3. The real trick is to set the preprocess option to LOCKED when your ready to set your scene up for rendering. This means that Lightwave will not calculate radiosity anymore, it will only look at the CACHE file. Now if you have geometry that doens't have any information baked in you will probably get some flickr or wierd splotches.

You can save many different angles of cameras into ONE CACHE file. This gives you more information for each scene to pull it's cache information from.

Good luck!

05-08-2012, 09:16 AM
Ahh thanks! :) The LOCKED option was what I was missing.

05-08-2012, 09:44 AM
No problem. Glad I could help. There are many other resources that describe all the settings in much more detail (and probably more accurate) than I can. There are ways to set the qty of rays, pixel sizes etc. to get cleaner or faster renders even with interpolation turned on.

However there are times when you may need to just bite the bullet and have Monte Carlo does it's thing. We had just that situation on a recent project where we had tons of animated objects, object fades etc.etc...

Take care.

06-13-2012, 10:38 AM
I have posted this in the old HardCore forums but I am aware not everyone has access to that....

I did a trawl of the many animated radiosity cache threads and have come up with no answers to my issue.

Ok so a little around the scene....

1600 frame animation
Only the camera is moving
MC radiosity baked to cache at steps of 5 frames in around 3 hours
Set preprocess to locked after baking

when it comes to render the scene proper nothing happens... that is to say it finds the cache for the first frame and renders the radiosity solution in 0.8 seconds but then nothing, the render window is black and it just seems to hang.

Sometimes i get and estimated time for completion other times i dont. This happens whether i a trying to render a frame or a scene. The render time when it appears is over 360hours per frame!!!!

Have i missed something?

Interestingly the whole animation will render with no cache in around 18 hours.

Any help much appreciated

06-13-2012, 01:46 PM
copy paste from my response there:

You made an animated GI cache? Which is no cached solution yet, it is caching positions where it needs a solution. If you did 5 frame skip on a 1600 frame animation, I bet you that it has insane amounts of sample point positions placed. )use radiosity flags to get them shown)

Without going into details about the animated radiosity cache, simple solution:
tick off the "animated" box. And set frame skip to 25 and try again. Yes you are caching an animation but that tickbox is for moving objects etc other than the camera.

If only camera is moving it is all you need, to have cache on.

Ow and read this:
It is the best thing you can read about this topic.

I have a feeling that I may have misunderstood your issue, but even your topic is "animated radiosity cache", which is not what you need. imho

06-13-2012, 02:27 PM
Thanks for the response.

I was using the animated cache as I was getting flickering without it. Ill give your suggestions a go. Since the original post I have tried with a step of 250 frames and i still came across the same issue.....