View Full Version : LW2019 Rendering Images with Alphas

04-04-2019, 07:24 AM
Maybe because I'm a generalist and don't use Lightwave 100% of the time during my work day, but it seems to me rendering a single image with an alpha channel in LW2019 has become significantly more convoluted than in previous versions. I wonder if it has something to do with the new rendering system? The price you pay for a huge increase in render quality maybe comes with more setting variations? There are so many more settings to keep in my when rendering and I must be missing something in either the GI, Volumetric or Output tabs.

04-04-2019, 08:16 AM
F9 and Save RGB=>Save PNG32 in the Image Viewer window still works fine for me. For sequence rendering with alpha, you don't have to use the separate Alpha channel buffer if you don't want to, instead changing the Final Render buffer output to PNG32 or another 32-bit format which includes the alpha channel.


04-04-2019, 09:50 AM
What was your process (and file format) in previous LW versions?

Some of the struggle may involve the way another app reads in the alpha channel. For example, depending on the file format and buffers used for LW output, Photoshop may show the alpha as a distinct channel in the Channels panel, or it may just bring in the file with layer transparency.

04-04-2019, 02:21 PM
The renderings are about the same but the way you composite it over a background might be different. It's either multiply or unmultipied or something like that.

04-05-2019, 06:46 AM
I hear everything you all are saying and it used to be I never had to think twice about doing renders in Lightwave with alphas and opening them up in Photoshop with no problem. I just think I switched some small, little, overlooked setting in LW2019 and now I cant seem to get a render with an alpha layer. A small sample scene is enclosed if anyone has time to do a render and see for yourself. Thanks!

04-05-2019, 07:11 AM
Its the fog settings. Volumetrics are actual "things" rather than simple effects in the new renderer, so volume fog has an alpha, and since it fills the scene... there you go.

Either turn off the fog, or turn on legacy volumetrics to have it behave like the old fog.

04-05-2019, 07:38 AM
Bingo! That's it. Thanks so much RebelHill. I DO have most of your training series ... but have only managed to make way through about 1/3 of them. I'm sure you covered this in your latest LSR series.

04-05-2019, 08:28 AM
Probably not specifically this case, though there ought be enough insight in there to make it one of the things you may think of. Either way, its easy enough to check whats going on, just set your VPR to alpha view, and go toggling backdrop, or scene effects on and off, and it reveals itself quickly enough. Also lets you know immediately whats in the "actual" image alpha, and what's the result of save options/fileformat, etc.

04-05-2019, 10:13 AM
Awesome! For helpful tip. Thanks again.