View Full Version : True Alpha representaion in Image veiwer?

07-01-2014, 02:17 PM
I have some polys textured with a black and white image map on the transparency channel so that the edges fade off gently.

If I render out LW_PNG32 and bring them in to After Effects, it works good and comps over my background how I want.

If however, I comp them in LW, setting my BG in the Compositing tab, and then render as .LW_JPG, my fade doesn't work like I want. It does fade some, but I still have hard edges at the end of my geometry. This is also the view I get in the Image Viewer when I do a F9 render, which makes it difficult to visualize how it is going to look in the end.

I'm pretty sure this all has to do with premultiplying, which to be honest I have never really understood.

My questions are:
Is there a way to tell the Image Viewer to show me my alphas the way they are going to look when composited?
Is there a way to directly render a .jpg already composited like I want?


Also, in the Image Viewer, is there a hot key to pan, or any way to pan for that matter? Rendering 1080 HD is bigger than my screen, and dropping it to 50% is both irksome, and not very helpful for previewing sometimes.


07-01-2014, 02:24 PM

07-01-2014, 05:34 PM
Don't use JPGs. LW really doesn't like them very much. They always have problems with transparency; mostly due to the compression. Even at 100% quality there is some loss involved and that loss is all dumped upon what the algorithm thinks is an unimportant area.

You don't get scroll bars in the Image Viewer?

07-02-2014, 11:51 AM
I've been working in LW 9.3 on this project (thanks for your help with that Spherical) and no, I dont get any scroll bars in the 9.3 Image Viewer.

I'm okay with not exporting jpgs. Mostly though, I was hoping to see more representative view of my alphas in the Image Viewer. The F9 Image Viewer doesn't care what your render export settings are does it?

07-02-2014, 02:53 PM
JPG Does not support alpha channels at all, you don't get a choice between 24 or 32 bit with jpeg, use png or any other 32 bit format, As far as After Effects goes I think you'll need to set the alpha to premultiply? haven't looked at After Effects in a long time.

07-03-2014, 03:39 AM
(thanks for your help with that Spherical) and no, I dont get any scroll bars in the 9.3 Image Viewer.

That explains it. The scroll bars are a more recent feature; not certain which version (probably 10.x+) but I know that 11.x has them