7 Replies Latest reply on Jan 7, 2009 3:48 AM by OsakaWebbie

    Making star fields: Transparent layers for stars made with noise?

    OsakaWebbie Level 1
      I'm trying to do what David Bogie described here: David Bogie, "How can you create a flying through space effect?" #4, 16 Jul 2008 7:28 am. But I'm a real newbie in AE (I have 6.0 and have owned it for years but only used it about twice or so - I do everything else in PPro), so I'm getting stumped on basics. What kind of layer should I do this with? The choices in 6.0 are Text, Solid, Light, Camera, Null Object, and Adjustment Layer. I tried a solid black layer, but it is indeed very solid - when I make a second one, the first is never seen again. Null Object and Adjustment layers don't seem to respond when I put the noise and threshold effect pair on them, so they are apparently the wrong type for this. There seems to be no such thing as a Transparent layer type, or is there?

      A secondary question (sorry to put two questions in one post, but it's probably simple) is about the threshold effect. It seems that the result is either pure white or pure black - I started with noise of varying lightnesses and even color, but when I use threshold to thin it out (to make it more like stars), the result is only bright white dots and nothing else, no matter what threshold level I choose. Am I missing something simple?
        • 1. Re: Making star fields: Transparent layers for stars made with noise?
          craulmedia Level 1
          do you want to create a smooth flight trough a star field or a "light-speed" flight?

          here´s an example of creating stars with Ps and Ae http://library.creativecow.net/articles/velez_dean/Starfield.php

          if Photoshop is not available, you can create the background in Ae using a bigger composition first for creating stars with fractal noise, put the "stars" comp into a newly created (your TV Standard) Comp and continue with part two of the tutorial. you'll get the idea.

          otherwise you have to experiment with particle effects, 3D Space, motion blur, etc...
          • 2. Re: Making star fields: Transparent layers for stars made with noise?
            OsakaWebbie Level 1
            Update: I got around the transparency problem by using a Luma Key effect on all but the bottom layer (there is always more than one way to skin a rhinoceros). I now have three layers with noise/threshold effects to make random white pixels; each layer appears at a different time (nice and gradual using opacity) and scales from 100% to something larger. The motion looks okay when all the stars are distant, but as it goes along, it's not right - if these were real stars they would be out of view to the sides before they become huge white squares, but a simple change in a layer's scale allows too much enlargement (pixels becoming squares) before they disappear from view on the edges of the frame. Any ideas on how to do this better? If AE could enlarge pixels to circles instead of squares it would help some (stars are round, after all), but I still would need something that will do more "widening" of the field of view with less enlarging of the objects in it, if that makes sense. Very few of the stars should ever get any bigger than 3-4 pixels, in my opinion. Is this a job for 3D layers? I have never done that before.

            (Question #2 is still available for an eager answer, also - my specks-becoming-squares are all pure white, rather than varying pastels that stars would really be.)
            • 3. Re: Making star fields: Transparent layers for stars made with noise?
              craulmedia Level 1
              > Am I missing something simple?

              yes, an upgrade with lots of fancy plugins included (but please check the sys reqs first), or a good book and/or tutorial.
              • 4. Re: Making star fields: Transparent layers for stars made with noise?
                OsakaWebbie Level 1
                Sorry - I failed to do a refresh before writing my second post, so I hadn't seen your first post yet. Please don't be frustrated with me. I can't afford an upgrade (I'm using the Japanese version, and the prices here are outrageous), I own a good book, and I read/watch plenty of tutorials - apparently just not the right ones. Sorry that my lack of familiarity with AE terminology makes it hard to search for answers. And my familiarity with PPro makes AE harder to understand, I think - the windows look similar but the methods are very different.

                I checked out the tutorial you mentioned in your first post, and his stars are really nice (solves my question #2 - I'll just use that Photoshop file). I couldn't open his AE project file because it was 6.5, but I followed his instructions and recreated the comp myself. It's a very interesting twinkling-swirling stars thing, but what I mainly need is "camera" movement, which his doesn't have much of. I originally envisioned "light-speed flight", as you called it, actually passing by stars, but I can see that that's going to be too hard.

                What I didn't mention about my composition (because it's the part I already know how to do) is that I will zoom in on an image of earth - the idea is that the camera is approaching earth from way out there somewhere (I'm not going to bother with the rest of the solar system - this is just for the intro of a song video, not a lesson in astronomy). So I do need the appearance of some forward speed in relation to the stars. But I decided to abandon the idea of having visible stars that the camera actually passes by (because of the problem of the whole layer getting too big), so in my new scenario, we're starting out just far enough away that earth is too small to see, but all the stars will stay relatively distant.

                So starting with the comp from the tutorial, I tried to edit it for my purposes. I zeroed out the rotation completely, removed the keyframes for position so that each layer would still have a different position not change over time, and increased the amount of change in scale over time to make that more obvious. The problem I'm facing now is that something about the position of each layer is such that the scaling movement is not relative to the center of the video frame, so each layer is moving in a different direction as it scales. Real stars wouldn't do that - I need the anchor point in the middle for all layers. The anchor points started out as 500x500 (I guess because the original Photoshop file is 1000x1000), but since that wasn't working, I tried changing all the anchors to 360x240 (the middle of my NTSC comp), and also tried changing each of them to the same as the position value for the layer, but none of those three formulas is the answer. How do you get the anchor point for scaling to be in the middle when the original image is 1000x1000, the frame is 720x480, and the position is, to use one of the layers as an example, 355x370? I have searched the web and read various tutorials, but haven't found the clue.
                • 5. Re: Making star fields: Transparent layers for stars made with noise?
                  craulmedia Level 1
                  doneworry, no one will get frustrated with you, the point is to get you to a good starting point before you get frustrated.

                  for anchoring issues use the "pan behind tool" read this http://www.motionworks.com.au/2007/01/pbt/

                  reconsider what then been done with Ae 5.5 here
                  http://www.creativecow.net/articles/aftereffects5_5.html

                  sure Ae 6.0 is "weaker" than todays version
                  But reconsider how many effects in movies - most of them that you problably have been watched - have been entirely created with Ae b4 version 5.0?
                  • 6. Re: Making star fields: Transparent layers for stars made with noise?
                    Andrew Yoole MVP & Adobe Community Professional
                    Here's another tutorial which may be of assistance - you'll just need to reverse it.

                    http://www.videocopilot.net/tutorial/earth_zoom/
                    • 7. Re: Making star fields: Transparent layers for stars made with noise?
                      OsakaWebbie Level 1
                      Sorry, Thomas, I thought you were the one who was frustrated - it sounded like you felt I needed to either upgrade or study the basics on my own before attempting something like this. And I wasn't belittling older versions; I thought you were. Don't ya just hate that lack of voice inflection and facial expressions that you get in online communication...! Okay, onward.

                      I read about the Pan Behind Tool before (if you start searching for "anchor point" and "position" it comes right up), but then, as now, I don't understand how it works with layers that have already been moved out of whack. And since my last post I have done way more to my comp: To try to reduce the afore-mentioned problem while still getting a variety of star patterns in my layers, I made all the positions 360x240 (which is the same as what I left the anchor points at) and introduced rotation instead - that didn't solve it, but it looked a little better. Then I decided that the time before the earth appeared was kinda boring, so I learned about parenting, made two of the star layers children of the third one, and bezier'ed some position and rotation action to the parent, so that it will look like the viewer's ship is changing direction as it's flying, and then when it steadies its heading, earth begins to appear. It's not bad - the flying motion takes your attention off the layer discrepancy. But when I showed it to my husband, who had conceived the original idea of this sort of video for the song intro, he instantly noticed the relative motion without me mentioning it - he didn't know what to call it, but commented that my stars seemed to be moving around. Yup! I am now convinced that it's not just anchor points, but the fact that the scale is different on the three layers. I even tried adjusting the rates of change of the scale to be the same on all layers (2X over the course of a period of time - one is 100->200, another is 60->120, and the third is 50->100), but they still move funny. Oh, well. So I finally just rid of the keyframes on the two child tracks altogether and let the parent do all the enlarging. I don't know how that differs from having each layer enlarge the same ratio over the same course of time, but somehow it is - the funny movement is gone. Unfortunately that eliminated the final thing that made the layers different - the current result could have been achieved simply with three layers in Photoshop. I would have liked to have "closer" layers enlarging faster than "farther" ones (that's the reason for multiple layers in the first place), but if they won't do so from the center point, it's just too weird. I have spent a whole day working on 18 seconds of video - I need to move on to the rest of my project.

                      Okay, now to address Andrew's post, which came in when this post was almost ready to send (I learned my lesson and checked before actually sending!). That's my kind of tutorial! In one sitting he teaches several techniques, effects, tools, unnumerable keyboard shortcuts, etc. Often when I watch a tutorial video, I learn just one thing in ten minutes, but this guy packs in the information. I will have to be careful to sort out what I can do and what I can't - I have 6.0 Standard, and he has Pro of some newer version (I don't know how new, but he was able to make great-looking stars in seconds using fractal noise, an effect I don't seem to have). As for using his idea directly, it had occurred to me that zooming in closer than I am would be cool, but I don't have any images for that. Do you know where one would get satellite images like that? Google Earth is copyrighted material, even though I assume the images it uses are not.

                      Wow, I learned a lot today - thanks to both of you for pointing me in good directions. AE is not as intimidating as it was yesterday! :-)