How to; Different percentage of transparency on one object ?

Wiew Posts: 24 Just Starting Out*

Maybe somebody can help me out ,

I want to put this clock film part in the sky ,I can set the transparantie of the clockbut I actually want the transparency to gradually go from 40% at the top to 0% at the bottom so that the clock below is on the bottom no longer visible

Anyone have any idea how I can solve this?


  • Triem23
    Triem23 Posts: 20,517 Ambassador

    So, you have two ways to approach this. Masks and Mattes.

    Masks are drawn directly on the layer to define transparent areas. If you want a straight-line linear fade, you just need to draw a rectangle mask around the area you want opaque and feather it out to create a fade.

    A Matte uses channel information (Red, Green, Blue, Luminance or Alpha/Transparency) from "Layer A" to define transparent areas of "Layer B." For a straight-line linear fade, you could create a black to white gradient on a plane with the Linear Gradient effect and use that as a matte source (white areas would be opaque, black would be transparent). With a Matte you have more options - for example you could create a Comp Shot with a gradient for a general fade, but use masks on white planes to draw the shape of the clock hands, match that animation and create a general fade where the hands are always opaque.

    These are a couple of Film Sensei tutorials on masking. I THINK the mask tool changed since these were made - instead of different icons for the different mask types, it's now a click-hold on the mask tool button to bring up a pop up of the different mask shapes.

    This is a Film Sensei tutorial showing how to use Set Matte to use pre-made black and white animations to create transparency.

    This is the last comprehensive masking tutorial from FXhome. Since then the interface has changed, so watch the Film Sensei tutorials first to see a more current interface, but this tutorial is more in depth on what masks can do.

    Finally, this tutorial is even older, but it goes into how masks, mattes, maps and keys are all variations of the same thing. It's long, but it's good basic theory, and has a brief overview of all of the different 2D compositing tools. Then again, I'm biased. It's my tutorial. 😉

  • Wiew
    Wiew Posts: 24 Just Starting Out*


    Thank you very much you have helped me a lot

    You can find the result in the show off section ;-)

  • Triem23
    Triem23 Posts: 20,517 Ambassador

    Glad to help! 👍