F Curve Question

# 1 12-08-2010 , 10:10 AM

Lead Modeler - Framestore
Join Date: Feb 2003

Location: UK

Posts: 6,287

Hi All

I have a small dilemma,
I have a car on a motion path but wish to duplicate it. At the moment the duplicate (with input connections) creates a second car but it shares the one fcurve so I can't offset the second car - does that makes sense? Is there a way of duplicating it but having control of its own fcurve. I could dupe the path but I have hundreds of cars and am looking for a clean solution.

cheers
J

Quote

# 2 13-08-2010 , 11:33 AM

Lifetime Member
Join Date: Feb 2010

Location: Australia

Posts: 4,255

I dont know enough about it Jay but cant you (maybe Maya doesnt have it) use 'array' to make multi copies of the paths really quick???

bullet1968

"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes

Quote

# 3 13-08-2010 , 12:33 PM

Lead Modeler - Framestore
Join Date: Feb 2003

Location: UK

Posts: 6,287

Not sure mate

we are looking at it here at work, we are just waiting for a TD to be hired but need a fast solution for some previz work we are currently doing

cheers
Jay

Quote

# 4 13-08-2010 , 04:43 PM

EduSciVis-er
Join Date: Dec 2005

Location: Toronto

Posts: 3,374

I've thought about the problem a bit, and I think the most efficient solution would be to write a script to handle it. But other than that, I can't really think of a simple solution (with relatively little experience in motion path animation). I've been trying to learn MEL/python, so maybe this would be a good chance to do some practice. I might give it a try after work today, but no guarantees I'll get anything to work :p

So you need ~100 cars on a single motion path, offset only in time?
That is, all the cars will follow the exact same line of motion, but at different times? Do they also need to vary in speed?

-stwert

Website - Blog - YouTube - Vimeo - Facebook - Twitter

-->How to Effectively Ask Questions on Forums<--

Last edited by stwert; 13-08-2010 at 04:46 PM.

Quote

# 5 13-08-2010 , 09:59 PM

Lifetime Member
Join Date: Feb 2010

Location: Australia

Posts: 4,255

I know SFA stwert but I think thast what he needs. I thought along similar lines...a script that maybe has a random function in it. So car 1 = car 2 = etc etc and maybe another function as you say with different key frame points and frame speed if they need to be different speeds???

keep us posted?

cheers bullet

bullet1968

"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes

Quote

# 6 13-08-2010 , 10:38 PM

EduSciVis-er
Join Date: Dec 2005

Location: Toronto

Posts: 3,374

Sorry, what's SFA?

-stwert

Website - Blog - YouTube - Vimeo - Facebook - Twitter

-->How to Effectively Ask Questions on Forums<--

Quote

# 7 13-08-2010 , 11:43 PM

Lifetime Member
Join Date: Feb 2010

Location: Australia

Posts: 4,255

Sweet F*** All mate LOL

bullet1968

"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes

Quote

# 8 14-08-2010 , 05:21 AM

Registered User
Join Date: Feb 2005

Location: This Place

Posts: 220

Here's a script that will allow you to control an object's position on a path, based on some other object's position. This can be adapted to run objects at different speeds as well. Note - the objects will 'loop' around the ends of the curve (starting back at 0) once they reach the end of the curve (the curve is assumed to be in the range of 0->1)
I originally developed this to control tank treads. You should be able to dump it into the uValue parameter as an expression. I'm afraid you may be on your own for creating duplicate cars, though (never set that part up, I'm afraid).

//general form of equation:
When ((primary tread's path uValue) + (uValue moved from primary tread) less than 1):
(primary tread's uValue) + (uValue moved from primary tread);
Example:
if ((tread0Path.uValue) + (0) < 1) {
tread1Path.uValue = (tread0Path.uValue) + (0);

else:
subtract one from above
Example:
} else {
tread1Path.uValue = -1 + (tread0Path.uValue) + (0);
}

Book Wise

https://X4nd5r.deviantart.com

Quote

# 9 14-08-2010 , 05:51 AM

EduSciVis-er
Join Date: Dec 2005

Location: Toronto

Posts: 3,374

Alright, here's my script:

https://dl.dropbox.com/u/3447479/highwayMaker.py

It's python, and it may or may not work user added image

Start with a car, and a path, but not connected to it.
Run the script (in the editor or whatever) which will give a simple UI. Input the number of cars and the number of frames within which all the cars should traverse the path.
Then select the car, select the path, and hit execute.

The cars will begin at the start of the path at the current frame (so watch at what frame you hit execute) and randomly start moving down the path. They all go at the same speed (which is the number of frames/number of cars, you can modify the script to go more dense, more sparse, more randomly).

You can also modify axes, path parameters, max values etc in the script if need be, pretty simple stuff.

I don't know if this fits the bill (I didn't get many parameters to start with :p) but I learned a ton with this exercise about scripting, so I don't really care if no one can use it.

-stwert

Website - Blog - YouTube - Vimeo - Facebook - Twitter

-->How to Effectively Ask Questions on Forums<--

Last edited by stwert; 14-08-2010 at 05:53 AM.

Quote

# 10 14-08-2010 , 06:55 AM

Lifetime Member
Join Date: Feb 2010

Location: Australia

Posts: 4,255

Xander and stwert...well done. It doesnt matter stwert..you had a go at it. Both of you well done...I must learn Python one day.

bullet

bullet1968

"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes

Quote

# 11 14-08-2010 , 02:06 PM

Lead Modeler - Framestore
Join Date: Feb 2003

Location: UK

Posts: 6,287

dudes many thanks

I will have a look on monday at work.

cheers
Jay

Quote

# 12 14-08-2010 , 04:05 PM

EduSciVis-er
Join Date: Dec 2005

Location: Toronto

Posts: 3,374

K, apparently I had an error with the window creation, which didn't show up until I re-opened Maya this morning.

So small update:
https://dl.dropbox.com/u/3447479/highwayMaker.py