#Rule-based animations
12 messages in this thread
Simple question:
How can one animate an object (for example a car moving over a terrain)
so that the car mesh never passes through the ground mesh? (Thereby simulating
a primitive form of gravity, if the car mesh is linked to something below the
ground. I think..).
Any help would be greatly appreciated.. as well as a reference to any
relevant reading material.
Richard,
<< How can one animate an object (for example a car moving over a terrain) so
that the car mesh never passes through the ground mesh? (Thereby simulating a
primitive form of gravity, if the car mesh is linked to something below the
ground. I think..).>>
What you're describing (car going straight) could be viewed as linear motion.
When setting positions in the keyframer, the default tension, continuity and
bias are set for non-linear motion. See pg 8-98 to 8-101.
jonas[adesk]
You missed Richards point Jonas. He wanted to know if he could have a car or
whatever travel over a "terrain" object while keeping the car attached to the
ground the entire time. This would not be easy actually, and really has nothing
to do with the TCB controls. Maybe one of the people involved with accident
reconstruction could offer some good advice.
Dave Mennenoh
Hi, David. I just finished an animation where this issue arose. Actually,
Jonas is correct — the TCB sliders will have to be adjusted — in my case, The
Tension slider specifically, had to be set at or near 50 at many keyframes, and
keyframes had to be set literally every few frames during one portion…it's
difficult to acheive what is described, but persistance will pay off. I would
very much like to see a reply from someone involved in accident reconstruction.
Regards, Connie
David,
>> He wanted to know if he could have a car or whatever travel over a "terrain"
object while keeping the car attached to the ground the entire time. <<
Actually, I've worked with some accident recreation specialists with 3DS and
its not that difficult to do. Basically what you want to do is creat the cars
motion path in the lofter, using the terrain as the background and then import
that path into the keyframer. Also whatever path was used to create the terrain
can be used as a path for the vehicle as well.
-JE
>>Basically what you want to do is creat
>>the cars motion path in the lofter, using
>>the terrain as the background and then
>> import that path into the keyframer.
This works, but with one caveat: Following this procedure (which I did a while
back for a production job) the car will just follow the terrain while rigidly
staying in its original rotational position. So then, you use path/follow,
right? Well, that makes the car follow the bumps better, but still you will
have wheels that appear to plunge beneath the road at times. Tedious keyframe
editing is about the only approach to keeping the four wheels tangential to the
road on terrain that has any bumpiness at all. If your road is pretty flat,
this wouldn't be much of a problem.
I think the ultimate solution will be a KXP that does object collision
detection. This is one of the new KXP possiblities that hasn't come on the
market yet. It is entirely possible to set the car at the start of the road,
run the kxp, click on the road, click on the car, and the keyframes are there,
with 4 point contact (the four wheels) all the way through.
Jim
Jim,
If you set follow with Banking off the tires shouldn't go into the terrain.
Actually I think its best to use a dummy object and attach the car to it. That
way if you need to you can give the car some shock absorbtion properties.
Yes collision detection will be nice for a variety of applications.
-JE
Collision detection will be great, and you can bet your bannanas that someone
is out there working on it (I even know who it is <evil g>). The down side
will be potentially horrendous calculation times for high-res collision
detection and other complex dynamics effects.
John Tissavary (LUNA cie)
I was originally hoping that collision detection had alredy been implemented,
and that I would be patiently told I had been staring it
right in the face. I am glad, however, to hear that someone expects to make it
possible soon.
Thanks, all.
>> I even know who it is <evil g>)
Na na na Naaaah na… (sure rub it it!)
The Positron people are doing a dynamics KXP for collision detection, friction,
gravity, etc. (800/365/1002)
– G
Isn't Richard looking to create a three dimensional path that uses the
intersection of the horizontal path with the terrain?
Then he could just adjust the rotation of the vehicle to allow for changes in
the angle of the vehicle? (that's Angle of Attack for you pilots out there <g>)
tjl