Velocity Curve?

#1

Is there such a thing as a velocity curve in Softimage? I have done some animation in another 3D package and one of the most useful tools I found in there was the velocity curve.
It’s really just a curve that shows you how fast a selected element moves. It’s a really good tool for removing any unwanted speed-ups or slowdowns in an animation. Does Softimage have something like that? Or alternatively, how would you deal with that sort of problems in Softimage?

#2

Animate>Tools>Plot>Curve may be what your looking for. You can use this to plot the motion of a single object or a cluster w/center on an object.

#3

In the Global position of an object you have the option to compute velocity and acceleration, I’m not sure how you access that from something else though. Don’t think you can get a curve from it…

#4

“…It’s really just a curve that shows you how fast a selected element moves. It’s a really good tool for removing any unwanted speed-ups or slowdowns in an animation. Does Softimage have something like that? Or alternatively, how would you deal with that sort of problems in Softimage?”

Are you talking about function curves (or animation curves)? Function curves are essentially plots of velocity. The slope of the curves at any point shows acceleration. Certainly these would allow you to easily control “unwanted speed-ups or slowdowns” by simply tweaking the curve. Where a curve is linear the velocity is constant. Any change in the linear portions of a function curve would mean an acceleration or deceleratoin.

Sorry if I have misunderstood.
Ohmanoggin

#5

I think we’re both talking about the same thing here. It’s what you get in After Effects or Electric Image (the package I’ve been using so far). Is it correct to say Softimage doesn’t have this?

I’m really surprised about this. It’s such an obvious thing to have, or does that betray too much of a motion graphics way of thinking on my part? :slight_smile:

I did notice that by using “set key on path”, you get the sort of behaviour I’m more used to. You even get a sort of velocity curve-ish F-curve (pathcns.perc) which is good. But the thing that really puzzles me is, that to set a key on a path, you can’t use the “K”-key. Is there a way (script, plug-in…) to do this? Once you’re animating on a path, surely every key you set with the translate tool, really is meant as a key on that path, no?

Sorry, if my questions are all over the shop, but I’m trying to get my head around a new way of working.

#6

View > Animation > Animation Editor

Or just press the number “0” key on the Top of the keyboard (not the numpad on the right).

#7

Quote:
Originally Posted by Ohmanoggin
… Where a curve is linear the velocity is constant. Any change in the linear portions of a function curve would mean an acceleration or deceleratoin.

Q: I think we’re both talking about the same thing here. It’s what you get in After Effects or Electric Image (the package I’ve been using so far). Is it correct to say Softimage doesn’t have this?

A: No, just the opposite. Softimage does have function curves and they work quite well.

Q: I did notice that by using “set key on path”, you get the sort of behaviour I’m more used to. You even get a sort of velocity curve-ish F-curve (pathcns.perc) which is good. But the thing that really puzzles me is, that to set a key on a path, you can’t use the “K”-key. Is there a way (script, plug-in…) to do this? Once you’re animating on a path, surely every key you set with the translate tool, really is meant as a key on that path, no?

A: On the property page for the path constraint, right next to the slider where you would move the object along the curve, just hit the key icon. Or better yet, hit <0> and view the function curve and edit it directly.

If you want a hot key- make one for “set key on path”. Although, you will already have the animation editor or the ppg slider up for the postion, so it may be easier to use one of these.

Ohmanoggin

#8

animating with speed & displace in after effects is a frecking nightmare. Good thing they introduced in cs4 normal x&y position animation at least…

#9

You see. I must be one of the few humans who actually likes the old speed/velocity F-Curves in After Effects. I have never seen the point of having X and Y curves, unless you have objects that only move horizontally or vertically.

Thanks for the tips Ohmanoggin

#10

If you imagine the tangent at a point on the curve you can see its velocity (easy if there is a key already) because it’s the first derivative. I don’t know much about scripting but if it is possible to maniupulate curves through scripting there should be plenty of algorithms to calculate the derivatives of bezier curves.

#11

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