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Rhothgar
06-27-2009, 05:09 PM
I'm working on making a nuclear explosion...

The problem I'm having is the banding in the initial bright blast.

I've used a lense flare here. I've also tried volumetic lights. Both have resulted in banding in the gradient of light as it goes from really bright to fading off...

It's probably something simple but I'm just not sure what it is.

I'm hoping to avoid post work on this if possible. I would really apprecaite any suggestions.

How do I get a smooth gradient in the light?

Thanks!

Mr Rid
06-27-2009, 07:00 PM
The banding is in the image file compression, not the scene. What format are you saving your renders as?

Rhothgar
06-27-2009, 10:40 PM
This image is a jpeg but usually (when I'm ready for a final render) I save as a targa file.

I just rendered and saved as a targa file and it looks perfect.

Thanks!

Mr Rid
06-27-2009, 11:55 PM
Good deal.

The "LW_TGA24/32" saver is a compressed targa which usually does not have artifacting problems (ran into an issue with it only once that I recall). Let's see, things have changed since the last time I needed an uncompressed TGA but it looks like that would be the "LW_TGA_SRC" saver. I dont know what SRC means.

toby
06-28-2009, 03:22 PM
It might bite you on the arse if you need to compress it later though. This kinda thing can happen when you have a slight gradient stretched over a wide area, you can see this on dvd's and bluray's too. It's a limitation of 24 bit color, including the display; the banding doesn't exist in floating point images, but you'd have to see it on a high bit-depth display to know it, like, plug the computer into your plasma tv. (I bought a high bit-depth lcd tv, forgetting that all dvd codecs are 24 bit. doh! :grumpy:)

If it does rear it's ugly head later, you'll have to dither it somehow, or shorten the falloff distance for the flare.

Rhothgar
07-01-2009, 08:50 PM
Good deal.

The "LW_TGA24/32" saver is a compressed targa which usually does not have artifacting problems (ran into an issue with it only once that I recall). Let's see, things have changed since the last time I needed an uncompressed TGA but it looks like that would be the "LW_TGA_SRC" saver. I dont know what SRC means.

Yeah I've been using the "LW_TGA_SRC" saver too. I'm glad I'm not the only one that doesn't know what SRC means... It seemed to just come out of nowhere.

Rhothgar
07-01-2009, 09:07 PM
It might bite you on the arse if you need to compress it later though. This kinda thing can happen when you have a slight gradient stretched over a wide area, you can see this on dvd's and bluray's too. It's a limitation of 24 bit color, including the display; the banding doesn't exist in floating point images, but you'd have to see it on a high bit-depth display to know it, like, plug the computer into your plasma tv. (I bought a high bit-depth lcd tv, forgetting that all dvd codecs are 24 bit. doh! :grumpy:)

If it does rear it's ugly head later, you'll have to dither it somehow, or shorten the falloff distance for the flare.

Yeah I've seen that too (banding on dvd's etc)... I took a look at it on my other comp with a better display and it looked quite a bit better. thanks for your comments. I haven't rendered something like this for some time...actually I don't think I've ever used a lense flare like this before... so the banding was a little off putting and unexpected.