any way to cheat spline interpmode to circular-like of jit.anim.path ?

    Julien Bayle
    Jan 03 2013 | 10:11 pm
    Hi there, I need to create a circular movement of a jit.gl.cam around a static point. jit.anim.path is perfect for this purpose.
    how would I handle this using spline and a reasonable number of points in the path ?
    subsidiary question: would I use jit.anim.path to keep the cam to look at the same point all along the movement ?
    huge thanks for any leads.
    • Pedro Santos
      Jan 04 2013 | 1:18 pm
      I would just use a pair of sin / cos functions to build a circular shape and to drive the camera... and a fixed lookat position. If you want to really use jit.anim.path, i guess you could feed this position data to add points in jit.anim.path...
    • Julien Bayle
      Jan 04 2013 | 2:24 pm
      I don't know which one would be the most cpu consuming. sin/cos usually consumes but in Max, I guess they involve some lookup tables or like. moving the cam, I don't achieve to fix the lookat. I mean, if I move the cam, the lookat attributes don't change BUT in fact, the cam doesn't look at the right point. (I'll play with other parameter like tripod etc.. I don't know)
      Using 8 points distributed on a circle, I did that using jit.anim.path at each point I set up the setrotatexyz and that seems to work fine
    • Julien Bayle
      Jan 04 2013 | 7:12 pm
      @pedro, I finally implemented cos/sin as it comes more natural. I need to make the speed of rotation variable. I'll probably increase the resolution of the [counter] and use some [line] wizardry :)
    • Rob Ramirez
      Jan 04 2013 | 7:16 pm
      use the locklook attribute to lock the camera's lookat point.
      i would simply feed the circle points to a jit.anim.path, and control the speed using the rate attribute.
    • Julien Bayle
      Jan 04 2013 | 7:35 pm
      Hi robert and thanks for your answer. got it for locking lookat. about the jit.anim.path, I guess I should append my points list with a reasonable number of points and use spline interp. testing that...
    • Ben Bracken
      Jan 04 2013 | 9:30 pm
      Rob showed me how to use matrix input to anim.path. This way you can generate the points with a jit.expr or jit.gen:
    • Julien Bayle
      Jan 05 2013 | 2:26 pm
      This works fine! THANKS. Doing that with jit.gen and playing with a variable path radius.
    • Pedro Santos
      Jan 06 2013 | 7:05 pm
      How do you control the spline interp? Or are there some kind of "bezier points" to control its curvature, or at least a parameter to control its width?
    • Rob Ramirez
      Jan 07 2013 | 9:20 pm
      the spline in jit.path (and anim.path and gl.path) is automatically generated using the Catmull-Rom method. you can adjust the curve by editing these default handle values. take a look at the gethandle and edithandle messages, and take a look at the "editing" tab of the jit.path help file. remember to disable @autohandles if you plan to edit your handle values.