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View Full Version : Applying glows in post-process



Phil
07-24-2005, 04:46 PM
I'd like to be able to do the following for post-process glows, but cannot see how to get the data out from LW in a usable way :

1) Apply different glows (intensity, colour) to different areas of the frame
2) Apply glows from 1) in reflections, refractions, etc.
3) Mask glows based on textures applied to surfaces (noting 1) and 2) above)

I couldn't find anything about this despite a fairly lengthy trawl so any advice would be greatly appreciated.

riki
07-24-2005, 11:37 PM
If you use something like Corona, make sure you check the 'conribute to mask' option.

Phil
07-25-2005, 04:45 PM
Hmm. What I am after is a way to generate glow masks from LW for use in something like After Effects, Digital Fusion, etc. I'm not sure how to do this given different glow setups in the same scene. I had hoped that there would be a way to include the data in the output from a single pass, but none of the exporters seem to cater for this.

Given that, I'm wondering what the best option is for generating masks that also include the effects of raytracing (reflected / refracted glows). I'm unsure that Corona caters for this, but will take a look.

Phil.

UnCommonGrafx
07-25-2005, 04:59 PM
Look at the rpf format and the use of object/surface IDs. I've used it and it seems that's the one format that, though it is just one file, holds lots of info about the 3D scene, itself.
Using a program that handles rpf, like df/x, you can split off those pieces to apply glow to and then merge it all back.
Otherwise, yes, lots of little passes. At least they should render quickly.

Phil
07-26-2005, 04:47 PM
Setting them up will be a pain though. I'll run some tests with the RPF suggestion though - hopefully that will be usable. :)

Thanks.

Phil
08-01-2005, 03:40 AM
Hmmm. The RPF exporter shows options for material/object based output, but there doesn't appear to be any such output in the RPF file. After Effects doesn't show it in any case.

There is no documentation to be found on these settings beyond a very brief overview in the online help and manual. That's disappointing. I've mailed Deuce, but would welcome an example of how to get this setup working (assuming that this isn't fundamentally broken).

Red_Oddity
08-13-2005, 02:41 AM
My suggestion is rendering out channels as different passes, and when harddisk room permits i suggest using 16 or 32 per channel (I suggest using ASA buffersaver (http://lw-fin.org/plugins/asa/bs/plug_bs.html) with SGI64 files or HDR/EXR/FLX/IFF)

As for RPF in AFX, sorry, AFX is a piece of horse manure when it comes to compositing...I suggest using Digital Fusion.

This example was done using a 32bit output (single colorpass) with defocus, glow and grain done in post (Digital Fusion).

http://sven.pinkyandtheskybunny.nl/images/stadje_grade0000.jpg

Phil
08-16-2005, 06:14 PM
Hmm. The only remaining question would be whether that plugin can export data to allow glows to be applied by texture. By way of example, suppose your windows in that shot had textures applied, giving the illusion of shadows being cast through the windows by furniture, etc. You would only want glows on the bright areas - not the all of the window surface. I'm not sure if there is a way to accommodate this and I haven't yet been able to find out for myself - hopefully I'll get a chance tomorrow.

Red_Oddity
08-17-2005, 03:29 AM
Hmm. The only remaining question would be whether that plugin can export data to allow glows to be applied by texture. By way of example, suppose your windows in that shot had textures applied, giving the illusion of shadows being cast through the windows by furniture, etc. You would only want glows on the bright areas - not the all of the window surface.

I not quite follow, with floating point data you can pin point exactly what areas are the hotspots for your glows (which areas on the picture have such high intensities they would, on a real lens/film stock, start blooming/glowing)
With float data a white pixel can go beyond the 255,255,255 you see on your monitor...one white pixel could have a value of, indeed 255,255,255 (or 1.0, 1.0, 1.0 in float) , while another pixel could go way beyond those linear boundaries, it could have a value of say float 5000.0, 5000.0, 5000.0