Page 1 of 3 123 LastLast
Results 1 to 15 of 41

Thread: Bezier spatial curves tied to temporal ones?

  1. #1
    Super Member
    Join Date
    Dec 2012
    Location
    At my desk
    Posts
    656

    Bezier spatial curves tied to temporal ones?

    This is obviously a beginner question, but with the mess of manuals and addendums I couldn't find much about it.

    I'm doing a simple camera animation for one of the sample projects in the 11.5 content, a scene called HDRI Spheres, and I wanted to use spatial bezier curves to avoid unnecessary extra keyframing. However I'm find an odd behavior I haven't seen in any program. I see the camera path in the viewport, but I can't do anything with it in there. On top view, clicking right on the plus sign simply selects the object behind it, which is the floor.

    So I can't find a way to apply a spatial bezier curve from the viewport, but the interesting thing is that if I set bezier curves in the graph editor, which is supposed to be only temporal, it also sets spatial curves for the selected keyframes. As I'm changing the bezier curve on the graph editor, I can see the spatial curve changing in the viewport.

    This is really bizarre, and I'm sure there has to be a way to untangle the two, because all the TV shows and things I've seen over the years made in Lightwave would look really weird if the two types of curves were directly tied to each other. I imagine there may be some situation where it may be useful to somebody, but I can't think of any.

    Either way, how do I disable this, and how can I edit the spatial curve in the viewport?

    Thanks
    Last edited by Sebasvideo; 01-30-2014 at 12:40 AM.

  2. #2
    Super Member
    Join Date
    Aug 2006
    Location
    S
    Posts
    3,511
    I think you might be confusing the graph editor's "temporal" splines with animation paths. Spline Control is the 11x tool for such things but it no longer requires a curve object.

  3. #3
    Big fan of coffee raw-m's Avatar
    Join Date
    Jul 2003
    Location
    London
    Posts
    2,333
    It's been a real pain in LW before Spline Control. If you already have your path mapped how you want it an alternative maybe to add a null and copy your Cameras motion to it, then on the Camera add DP Kit's Nodal Motion and point it to the null. The scalar inputs will give you a nice smooth path along the path.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	dp.png 
Views:	67 
Size:	25.7 KB 
ID:	119725  

  4. #4
    Goes bump in the night RebelHill's Avatar
    Join Date
    Nov 2003
    Location
    jersey
    Posts
    5,763
    There's no such thing here as a spatial curve vs a temporal one.

    Curves in the graph editor represent the position/rotation of an item against time... that's it. As has been mentioned, you can use spline control... where the Z axis represents distance traveled along the spline, thus the rate of change you key/curve on that Z axis becomes the speed along the spline path.
    LSR Surface and Rendering Tuts.
    RHiggit Rigging and Animation Tools
    RHA Animation Tutorials
    RHR Rigging Tutorials
    RHN Nodal Tutorials
    YT Vids Tuts for all

  5. #5
    Super Member
    Join Date
    Dec 2012
    Location
    At my desk
    Posts
    656
    Quote Originally Posted by meshpig View Post
    I think you might be confusing the graph editor's "temporal" splines with animation paths. Spline Control is the 11x tool for such things but it no longer requires a curve object.
    No, that's my point, I'm not confusing them. One thing is a temporal curve, as they are in the graph editor, and a different one is a spatial curve, which you modify to make the keyframed object, camera, etc move along the animation path in different ways, so if you want the camera to travel from point A to B in a rather circular motion, you modify the bezier curves on the viewport. That's the way it works in most applications.

    To illustrate my point I took a couple of screenshots. In the first one, I set all the keyframes to linear just to make it easier, so you can see they are linear in the graph editor and the animation path is also linear, which got that way right after I made the keyframes linear in the graph editor:

    Attachment 119730

    Then I selected the channel Camera Position Z, converted the first two keyframes to bezier and extended the handles. That is obviously intended to modify motion speed, it starts slowly, speeds up and then slows down again before arriving to the second keyframe. The problem here is that at the same time that I'm modifying the temporal curves, the spatial curves change along with it, which means they are linked:

    Attachment 119729

    This is a really odd behavior. In no program I ever used, even in After Effects, keyframe animation behaves this way. There's a clear difference between a temporal curve and a spatial curve. Reading the other replies I would think Lightwave is designed with these linked curves, but it doesn't make any sense to me. Converting these two keyframes to TCB Splines doesn't make it much different, in fact it gives me less control, because these splines can't be extended to make for smoother ins and outs. But the thing is with TCB Splines, the temporal curves still affect the spatial ones:

    Attachment 119733

    As for raw-m's suggestion, I'm trying to find a way that is LW native, not through the help of a plugin, because this is something that every other program I used has. I'm trying to learn more Lightwave to determine whether to keep it or sell it, but if in Lightwave spatial curves are tied to temporal ones, that's it for me. But I really hope they're not because it just doesn't make any sense.

  6. #6
    Goes bump in the night RebelHill's Avatar
    Join Date
    Nov 2003
    Location
    jersey
    Posts
    5,763
    Quote Originally Posted by Sebasvideo View Post
    One thing is a temporal curve, as they are in the graph editor, and a different one is a spatial curve,... That's the way it works in most applications.
    Its the same as LW in maya max, si and mb... motion channel curves are spatial, drawn against time. Thats all.
    LSR Surface and Rendering Tuts.
    RHiggit Rigging and Animation Tools
    RHA Animation Tutorials
    RHR Rigging Tutorials
    RHN Nodal Tutorials
    YT Vids Tuts for all

  7. #7
    Super Member
    Join Date
    Dec 2012
    Location
    At my desk
    Posts
    656
    Quote Originally Posted by RebelHill View Post
    Its the same as LW in maya max, si and mb... motion channel curves are spatial, drawn against time. Thats all.
    I don't get this. If in LW, Maya, etc, temporal curves were tied to spatial ones, almost every movie and TV show with CGI I've seen in the past ten years or more would look really weird. Let's say you're animating a car along a street. The car is stopped and you need it to go straight and then stop again, but obviously the car doesn't start going at 35 mph all of a sudden, it starts slowly and builds up speed. It also doesn't go from 35 mph to 0 in one frame, it stops gradually. So you position the car at point A, then move the slider to let's say thirty seconds later and then move the car object to wherever you want to position it. Then in the graph editor you set the two keyframes to bezier and extend the curves so the car starts slowly and gradually builds up speed to get to 35 mph and then modify the curve in the second keyframe to have it stop gradually. However, spatially, the car needs to move in a linear way from point A to B. But the way it works in LW when you modified the handles for the temporal curves, the spatial ones also got modified, which means that the car will not travel in a linear way, but it will make a weird curve at the beginning, travel diagonally along the street and then make another weird curve as it gets to the end.

    I hope I explained this in a clear way. I'm sure this can't be this way. I've seen tons of movies and TV shows with CGI and I can see bezier curves applied to motion, but they don't affect the motion path at all.

  8. #8
    You cannot control the handles of a motion path (even if it is set as "Bezier" in the graph editor) in the viewport. This is how Lightwave works.
    The closest thing to such a workflow is the path tool (Ctrl + y), it lets you move the keyframes of the selected object directly in the viewport, but you can't tweak the motion with the usual bezier handles, they're just not there.

  9. #9
    Vacant, pretty vacant pinkmouse's Avatar
    Join Date
    Aug 2003
    Location
    South Yorkshire
    Posts
    1,700
    I think you're getting confused. There is no such thing as temporal or spacial curves. The curve you see in the graph editor is exactly the same as the curve in the layout window, just split into it's constituent parts, and shown relative to frame number. It's the same thing.
    Al
    "I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while." Charles Fort

    My Website
    My Lightwave Tutorials

  10. #10
    Super Member
    Join Date
    Dec 2012
    Location
    At my desk
    Posts
    656
    Quote Originally Posted by pinkmouse View Post
    I think you're getting confused. There is no such thing as temporal or spacial curves. The curve you see in the graph editor is exactly the same as the curve in the layout window, just split into it's constituent parts, and shown relative to frame number. It's the same thing.
    You mean there is no such thing in Lightwave or in any application? Because I can tell you that at least in Modo and in After Effects you do have a clear difference between spatial curves or temporal ones. Please read my post above the car animation, I'm sure this can't be this way, maybe I'm not being clear enough.

  11. #11
    Goes bump in the night RebelHill's Avatar
    Join Date
    Nov 2003
    Location
    jersey
    Posts
    5,763
    Quote Originally Posted by Sebasvideo View Post
    The car is stopped and you need it to go straight and then stop again, but obviously the car doesn't start going at 35 mph all of a sudden, it starts slowly and builds up speed. It also doesn't go from 35 mph to 0 in one frame, it stops gradually.
    Lets assume we're working at a rate of 1 fps for this... (and the car is only moving forward on the Z).

    At 0... stopped.
    At 1... is at a few cm on Z. (currently moving at a speed of a few cm per sec).
    At 2... we have it now a couple hundred cm on Z (its reached 100 and some odd m/s speed).
    At 3... Its over 1m on Z (its now several hundred cm per sec).
    etc, etc.

    The speed at which something is travelling is just the result of how much space in moves through in how much time.... If you change somethings spatial position by ever increasing amounts with a fixed time step, u get acceleration... If the amount of positional change that occurs between any 1 time and the next is the same for every time step, you have constant speed. Its that simple. There is no separation between a space curve and a time curve, because the 2 are plotted AGAINST one another... Your motion curves (for each channel) represent transformation on a space time PLANE.

    What you're talking about is more along the lines of the already mentioned spline control...

    You have 1 spline (which is controlled in the viewport, NOT the graph, and which is distinct and different from the items motion path)... This sits as a "path" through space (of itself... internally) has no time axis. You can then attach an object to this path, ad animate its distance traveled along that path WITH time.
    LSR Surface and Rendering Tuts.
    RHiggit Rigging and Animation Tools
    RHA Animation Tutorials
    RHR Rigging Tutorials
    RHN Nodal Tutorials
    YT Vids Tuts for all

  12. #12
    Vacant, pretty vacant pinkmouse's Avatar
    Join Date
    Aug 2003
    Location
    South Yorkshire
    Posts
    1,700
    Is this the kind of thing you mean?

    Click image for larger version. 

Name:	Screen Shot 2014-01-30 at 15.48.31.png 
Views:	98 
Size:	217.5 KB 
ID:	119738
    Attached Files Attached Files
    Last edited by pinkmouse; 01-30-2014 at 08:52 AM. Reason: added scene file
    Al
    "I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while." Charles Fort

    My Website
    My Lightwave Tutorials

  13. #13
    Super Member
    Join Date
    Dec 2012
    Location
    At my desk
    Posts
    656
    Quote Originally Posted by RebelHill View Post
    There is no separation between a space curve and a time curve, because the 2 are plotted AGAINST one another... Your motion curves (for each channel) represent transformation on a space time PLANE.

    What you're talking about is more along the lines of the already mentioned spline control...

    You have 1 spline (which is controlled in the viewport, NOT the graph, and which is distinct and different from the items motion path)... This sits as a "path" through space (of itself... internally) has no time axis. You can then attach an object to this path, ad animate its distance traveled along that path WITH time.
    I think I may know what you mean here, that the longer you extend the bezier curve, it will somehow modify space because the object will be at a certain point at a different time depending on how much you extend the curve. If the handle is very short, it will be in a certain space faster than if you extend the handle much farther, in which case it's going to take longer to get to the same point in space. This is not a problem it's how it's intended to be. However, if you see my set of screenshots above, you'll see that modifying the handles for the first frame of the camera doesn't mean that the camera will take longer to get to the same point in space; it means that the camera will travel on a different path. That's my point, this doesn't make an ounce of sense, setting an object to travel at variable speeds between keyframe A and B shouldn't mean that the object is going to zig zag as is clearly the case in my camera animation in the screenshot above.

  14. #14
    Super Member
    Join Date
    Feb 2003
    Location
    Hamburg
    Posts
    1,571
    Quote Originally Posted by Sebasvideo View Post
    Because I can tell you that at least in Modo and in After Effects you do have a clear difference between spatial curves or temporal ones.
    It works the same in After Effects, but here you have an additional Speed Graph. If you click Separate Dimensions in the graph editor and modify just one channel you get the same effect as in LW.

  15. #15
    I think it also has something to do with Coordinate system : The curves in the graph editor are always in world space.
    When you tweak the Position.Z curve of your camera in the graph editor, you do it in the world space, not in the camera space. So you can't have a ease-in/ease-out movement unless you tweak ALL the curves (X, Y and Z)

Page 1 of 3 123 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •