velocity

[Ponthieux, Joseph G. (LARC-E1A)[LITES]]

I’d like to set an object on a path using velocity, or something similar to velocity at least, as the means of propagation along the path.

 

The idea is to animate a bunch of different objects, while on different paths of random lengths, so they all appear they are going the same speed regardless the path length.

 

I know that I can use velocity as a factor on particles, but these need to be models animated on paths.

 

Is this possible?

 

Thanks

 

--

Joey Ponthieux

LaRC Information Technology Enhanced Services (LITES)

Mymic Technical Services

NASA Langley Research Center

__________________________________________________

Opinions stated here-in are strictly those of the author and do not

represent the opinions of NASA or any other party.

 

[Alan Fregtman]

Sure! Do it with particles and constrain your things to them?

In 2013 (and maybe 2012) there's a built-in particle constraint in the ICE module under Kinematics, Effects->Transform Objects by Particles.

[Bradley Gabe]

On Wed, Jun 19, 2013 at 10:16 AM, Ponthieux, Joseph G. (LARC-E1A)[LITES] <j.pon...@nasa.gov> wrote:

I’d like to set an object on a path using velocity, or something similar to velocity at least, as the means of propagation along the path.

 

The idea is to animate a bunch of different objects, while on different paths of random lengths, so they all appear they are going the same speed regardless the path length.

 

I know that I can use velocity as a factor on particles, but these need to be models animated on paths.

 

Is this possible? 

Yes.

[Grahame Fuller]

You could do it with ICE kinematics, but I think this might be easier:

1. Apply a path constraint to get nice things like tangency and up vector for free.
2. Remove the animation on Path %age.
3. Apply an ICE tree to calculate the percentage yourself: get current time (make sure to turn Global on), multiply by desired speed, divide by curve length (this is why you can't do it with a simple expression), multiply by 100 for the percentage, and set self.kine.pathcns.perc.

gray

[Ponthieux, Joseph G. (LARC-E1A)[LITES]]

Spectacular!

 

This works exactly as I wanted!

 

I’ve got two objects on parallel curves traveling side by side at the same velocity. I’ve got a question however.

 

I’ve got a lot of these to set up. I’d like to create a compound out of the subtree, one I can reapply to other objects as I get them rigged. I only have one problem, I’d like the curve length to adapt to the path of the object to which the ICE tree is assigned. Is there any way to find that through self?

 

For example, if object is self, and self is animated on path crvlist30, I want self to find crvlist30 and then curvelength.

 

I was unable to find this through explorer and I looked in the object model documentation but I’ve been unable to isolate anything on the animated object which would point to the path the object is assigned.

 

Any ideas?

 

Thanks

 

--

Joey Ponthieux

LaRC Information Technology Enhanced Services (LITES)

Mymic Technical Services

NASA Langley Research Center

__________________________________________________

Opinions stated here-in are strictly those of the author and do not

represent the opinions of NASA or any other party.

 

[Grahame Fuller]

Unfortunately you cannot get an object's constraint connections in ICE.

You can, however, get its parent via the this_parent token. I just made a simple test parenting the object to its curve and it seemed to work, but there were some cycle warnings. These may be harmless, but I can't guarantee they won't cause problems in the future.

A more bulletproof method would be to add your objects and your curves to two groups in corresponding order, and write a script to build/rebuild the constraints and ICE trees accordingly.

gray

From: softimag...@listproc.autodesk.com [mailto:softimag...@listproc.autodesk.com] On Behalf Of Ponthieux, Joseph G. (LARC-E1A)[LITES]
Sent: Wednesday, June 19, 2013 12:16 PM
To: soft...@listproc.autodesk.com
Subject: RE: velocity

Spectacular!

This works exactly as I wanted!

I've got two objects on parallel curves traveling side by side at the same velocity. I've got a question however.

I've got a lot of these to set up. I'd like to create a compound out of the subtree, one I can reapply to other objects as I get them rigged. I only have one problem, I'd like the curve length to adapt to the path of the object to which the ICE tree is assigned. Is there any way to find that through self?

For example, if object is self, and self is animated on path crvlist30, I want self to find crvlist30 and then curvelength.

I was unable to find this through explorer and I looked in the object model documentation but I've been unable to isolate anything on the animated object which would point to the path the object is assigned.

Any ideas?

Thanks

--
Joey Ponthieux
LaRC Information Technology Enhanced Services (LITES)
Mymic Technical Services
NASA Langley Research Center
__________________________________________________
Opinions stated here-in are strictly those of the author and do not
represent the opinions of NASA or any other party.

From: softimag...@listproc.autodesk.com<mailto:softimag...@listproc.autodesk.com> [mailto:softimag...@listproc.autodesk.com] On Behalf Of Grahame Fuller
Sent: Wednesday, June 19, 2013 11:03 AM
To: soft...@listproc.autodesk.com<mailto:soft...@listproc.autodesk.com>
Subject: RE: velocity

You could do it with ICE kinematics, but I think this might be easier:

1. Apply a path constraint to get nice things like tangency and up vector for free.
2. Remove the animation on Path %age.
3. Apply an ICE tree to calculate the percentage yourself: get current time (make sure to turn Global on), multiply by desired speed, divide by curve length (this is why you can't do it with a simple expression), multiply by 100 for the percentage, and set self.kine.pathcns.perc.

gray

[Ponthieux, Joseph G. (LARC-E1A)[LITES]]

If I have to write a script it probably would make a lot of sense just to use the script to turn the whole process into a scripted add-on with a pick routine and everything. Sometime when I have time maybe, but not today. Looks like I’ll be renaming node values, woohoo!

 

Thanks Grahame, this was terrific!

 

--

Joey Ponthieux

LaRC Information Technology Enhanced Services (LITES)

Mymic Technical Services

NASA Langley Research Center

__________________________________________________

Opinions stated here-in are strictly those of the author and do not

represent the opinions of NASA or any other party.

 

From: softimag...@listproc.autodesk.com [mailto:softimag...@listproc.autodesk.com] On Behalf Of Grahame Fuller
Sent: Wednesday, June 19, 2013 11:03 AM
To: soft...@listproc.autodesk.com
Subject: RE: velocity

 

You could do it with ICE kinematics, but I think this might be easier:

 

1. Apply a path constraint to get nice things like tangency and up vector for free.

2. Remove the animation on Path %age.

3. Apply an ICE tree to calculate the percentage yourself: get current time (make sure to turn Global on), multiply by desired speed, divide by curve length (this is why you can’t do it with a simple expression), multiply by 100 for the percentage, and set self.kine.pathcns.perc.

 

gray