5 Replies Latest reply on Apr 11, 2016 8:59 AM by LizEntertainingTV

    Need help with multiple masks

    ted155

      I've been trying to create an effect in which I have "blotches" appear on a circle shape, as if they're corroding the circle to the point that you can see my dark blue background through the hole (like it burned through the circle). Using masks seemed like the way to produce this effect, and I was able to do it intially, but I've run into some problems.

       

      First off, I pre-composed the circle shape and the text that goes on it so that everything was in one composition (named full circle). Then, using the Pen tool and with the full circle selected, I clicked, like six points, to create a closed masked shape. It showed up as Mask 1 within the full circle comp. Then I checked Inverted to invert the mask so that that background showed through, like the circle had a hole in it. Everything looked exactly like I wanted until I tried adding a second mask on the circle. I followed the same process as I did in making Mask 1. A Mask 2 then appeared within the full circle comp. However, when I check Inverted on Mask 2, it "un-inverts Mask 1 and doesn't invert or do anything to  Mask 2. In other words, making a change to the one mask causes the opposite to occur to the other mask, while the other mask kind of disappears. Then while Inverted is checked for both maskes, and neither mask is really doing anything, unchecking Inverted on Mask 1 makes Mask 2 appear inverted (with the hole), but nothing happens with Mask 1 (i.e., it's not inverted with a hole).

       

      I'm not that familiar with masks, so I assume this is happening because they are on the same layer?

       

      I've tried different workarounds and nothing has worked or will get me the result I want. Not sure what I'm doing wrong, or if I just can't invert multiple masks in such a way that each mask behaves independently of the others.

       

      I'm using AE CS5.5 on a Mac Pro.

        • 1. Re: Need help with multiple masks
          Dave LaRonde Level 6

          You just need to play around with masks and mask modes so you get the hang of them.  If you go to AE's Online Help and type in "mask mode" as a search term, you ought to get some good... well, help.

          • 2. Re: Need help with multiple masks
            bogiesan Level 4

            > I've been trying to create an effect in which I have "blotches" appear on a circle shape, as if they're corroding the circle to the point that you can see my dark blue background through the hole (like it burned through the circle). Using masks seemed like the way to produce this effect, and I was able to do it intially, but I've run into some problems.<

             

            Create on e of the blotches in its own composition. You can even render it out as a little movie and reimport it. Using the alpha channel information from the movie, matte in your lower layers. Use as many copies of the blotch movie as you need.

             

            Corrosion and grunge effects are common. Search the AE tutorial sites and, as LaRonde suggests, the Adobe online resources for AE.

            • 3. Re: Need help with multiple masks
              ted155 Level 1

              Thanks for the help and suggestions. I ended up going with Plan B, which was to apply a Turbulent Displace effect to a circle shape and then keyframe the Complexity property to simulate morphing blotches on the larger circle.

               

              Then last week, more than a month after completing the video, I stumbled across a video tutorial that showed how to create masks, and it included adding multiple masks to a single layer. I went back to my comp with the blotches and tried the technique to see if it would work, and it did. Basically I needed to leave Inverted unchecked and the mask to Subtract for each one to achieve the hole in the circle that reveals the background. Then I keyframed the Mask Expansion property so the blotch would appear small at first and then grow.

              • 4. Re: Need help with multiple masks
                LJSMN

                Yes Ted, I can now see that subtract is a much better selection than invert for masking multiple shapes. Thanks for taking the time to come back and edit your post. Very helpful! :-)

                • 5. Re: Need help with multiple masks
                  LizEntertainingTV Level 1

                  Thank you for sharing that, I had exactly the same issue and by changing it from "invert" to "subtract" you solved my problem.