That damned triangle...again.

farss wrote on 10/23/2008, 6:16 AM
Got me going again and I'm certain someone else was complaining about this as well so I thought initially "Argh right, that's the bug they were complaing about". Well I / they was wrong.

If you comp two almost identical things and add a feathered bezier to the upper track and then apply an FX to the upper track like Curves you get an outline where the mask is. Change the order with The Triangle in the FX, problem is banished.

Thinking it though, Vegas is probably doing exactly what I've told it to do, just that's not the outcome I expected. The Curve is altering the alpha data in the feathered section of the mask, result seems to be to make it lighter hence the outline. Changing the pre/post triangle in the FX means the transparency is calculated after the Curves FX has done it's thing, no level shift, no outline.

Bob.

Comments

GlennChan wrote on 10/23/2008, 12:29 PM
That might be a bug in the Curves FX and the way it works with alpha. Not sure on the details... but it's like the Curves FX doesn't handle the premultiplied values correctly.

2- This is where I rant about the little triangle of death and how Vegas is giving its users rope to hang themselves with. ;)
Kim Nance wrote on 10/23/2008, 2:14 PM
Thanks so much for explaining this, Bob. I knew about the triangle, but didn't make the connection with changes effecting alpha channels. I have been concocting work arounds for years, not knowing the answer was so simple.

Regards

Kim Nance
Armadillo Post