6 Replies Latest reply on Jan 9, 2012 1:41 PM by fhxfhx

    AE 3D Space & Units

    fhxfhx Level 1

      Hi, I'm exporting a camera from Softimage to AE rt now and not really understanding how AE works in therms of 3D space units. I basically want to get a pipeline up and running where I can exchange stuff back and forth between AE and Softimage and therefore need an understanding of how AE "thinks" pertaining its xyz space. So far I've defined some distance to 0,0,0, mesurements in Softimage and imported a cam-animation from Softimage to AE ... now to be able to align a 3D-layer to the object I'm trying to track-match with the camera animation from Softimage I need to know how I can convert those Softimage units in AE units. I've tried out in AE to go to 4 views, and create nulls and move them the same distances I've measured in Softimage to find out about the conversion rate for AE, but having difficulties finding a 3-dimensional "size" of nulls or shapes, and nudjing stuff seems to be in screen increments of a pixel and not exact 3d-increments ... any hint on how this has to be managed would be great.

       

      Regards,

      Frank

        • 1. Re: AE 3D Space & Units
          Rick Gerard Adobe Community Professional & MVP

          You'll be better off looking for a script to export camera data from Soft Image to AE. A quick Google search brings up this. At the bottom is something that may work for you. I don't have Soft Image so I can't tell you if it works, but Soft Image forums would be the best place to look.

           

          Translating camera movement from a 3D app to AE without the use of an export script would involve some nearly impossible math.

          • 2. Re: AE 3D Space & Units
            Mylenium Most Valuable Participant

            Yes, AE thinks in pixels. There is no realworld unit system. Most import/export features in 3D programs simply assume a fixed conversion rate of e.g. 1000 pixels per meter and then all they do is convert the values accordingly. If something doesn't line up, the answer is probably more related to SI than AE. A common mistake is e.g. not keeping an eye on filmback sizes and camera focal length which may result in wrong projections....

             

            Mylenium

            • 3. Re: AE 3D Space & Units
              fhxfhx Level 1

              Thx for reply. I've used a script combination for SI-Export and AE-Import which works. I can also export simple polygon models along with the camera, which gives me the ability to measure those distances in AE, since when AE uses 3D-Layers it must have x,y,z units at least internally. Thing is that the scene rendered as video in Softimage layered in AE with the scene imported from Softimage visually matches for the first and last frame, but then drifts off a bit until the half of animation and then drifts back to sit in place at the last frame of animation again. In the script there is an info given that AE rounds up drop frame differently so there is a divergence, but I think it diverges too far for this being the problem, since drop frame divergence must be very small and imperceptible especially for short sequences such as 2 seconds etc.. Question would be how this can be fixed. Just jumping a frame would be way too harsh and visible. Maybe you guys have an idea.

              In case you wanna take a look I've uploaded the AE project and the scripts for research http://files.2he.com/SI2AE_01.rar

              I've read that the import/export to AE works with Maya and Cinema 4D, so probably finally can work with Softimage too. If I get this operating precise then this opens a whole other level of possibilities for Softimage users. Wonder why they haven't implemented that for Softimage too in the first place.

               

              Thx,

              Frank

              • 4. Re: AE 3D Space & Units
                Mylenium Most Valuable Participant

                Sounds more like the script is not correctly translating keyframes and makes assumptions about Bezier tangents. in that case it would probably be a good idea to bake the motion curves in SI and then make all the resulting keyframes linear, then import that into AE and again verify that all keys are temporally and spatially linear. Dealing with drop frames or other temporal discrepancies should not be a problem, as AE works in genuine time. The worst that can happen is tat you may need to time-stretch your layer with odd values, but usually the simpler solution is to work with discrete whole frames in the 3D program. Other than that you can always play around with comp setting vs. project settings vs. footage interpretation vs. time-stretching/-remapping. Somewhere between those four corners there is the setting that fits your case.

                 

                Mylenium

                • 5. Re: AE 3D Space & Units
                  fhxfhx Level 1

                  ya, sounds logic, will give it another good session to fiddle it out with these tips.

                   

                  Thx,

                  Frank

                  • 6. Re: AE 3D Space & Units
                    fhxfhx Level 1

                    found out that when I delay the cam layer for 1 frame, then everything matches perfect ! The symmetrically increasing / decreasing drift was a graphical result of the resulting overlay during the 3d course of animation only.

                     

                    Thx again,

                    Frank