View Full Version : Before you go on!

 Googler2402211 November 2004, 07:42 PMhttp://badnitrus.coasterbuzz.com/ Heres a link which may help you alot! This guy also has tutorials aswell! If you want to win this competition you better speak to this guy! his work is mind blowing! http://badnitrus.coasterbuzz.com/Coasters/SilverBullet/Pictures.htm
FrankFirsching
11 November 2004, 11:11 PM
This guy is really crazy. So many coasters. But the difference to this competition is, that he animates them using keyframes. The challenge is to do a convincing simulation of the coaster. But nevertheless some great work. :applause: Thanks for the link.

Frank

MConte05
11 November 2004, 11:15 PM
Actually, he recently developed his own MAXscript so all he has to do is click a button and it creates the coaster dynamics for him....

ACantarel
11 November 2004, 04:54 PM
Yep, incredible stuff there :cool:

"click a button and it creates the coaster dynamics for him...."

Hmm... the question is if it is really gravity based + friction + weightings for each waggon or just looking for XYZ-Values for the first waggon and the others follow.

But anyway, it looks cool!

André

MConte05
11 November 2004, 05:38 PM
Well, seeing how his animations typically follow the spline path. I think that he probably had the script calculate the Potential and Kenitic energy along certain percentages of the path, then had it automatically key-frame the car to that postion. Just my guess :shrug:

I have found that friction really isn't something thats incredibly important to figure in. As the co-efficent of friction for most modern steel coasters between the rails and the wheels is something like 0.03, a very small number that doesn't make much of a difference. In my simulations, the air restiance seems to be eating up more speed than the friction :shrug:

ACantarel
11 November 2004, 08:02 AM
Yes, you´re right. The friction (in the rollercoaster case) is a very small force in the real world. But because of the friction the rollercoaster could stick in the top of a looping. Or if you have the lower half of a circle, the rollercoaster would never stop in our CG-World. We don´t have air resistance so we need to add some friction.

André

MConte05
11 November 2004, 05:45 PM
Actually, in 3dsmax and reactor, I have "Do Not Simulate Friction" turned on, and something must be acting against my cars, because they don't have the same Mechanical Energy when they originally started. You can see in some of the test videos in my thread, the cars don't make it back to the original starting point, which is expected. But when I'm not simulating friction.....Then whats acting on the cars if its not air resitance? :shrug:

Edwin Braun
11 November 2004, 09:02 AM
Actually, in 3dsmax and reactor, I have "Do Not Simulate Friction" turned on, and something must be acting against my cars, because they don't have the same Mechanical Energy when they originally started. You can see in some of the test videos in my thread, the cars don't make it back to the original starting point, which is expected. But when I'm not simulating friction.....Then whats acting on the cars if its not air resitance? :shrug:

Reactor uses a constant "Drag Force" this shoudl be on by default. This is the secret force you see i nyour animations. This drag force is used to get the dynamics stable in the end. Sometimes this works but most of the time reactor simulations tend to "explode".

edwin

Sir_Vuclan
11 November 2004, 04:38 PM
Using Reactor 2. I have the drag turned off as well as friction, but the coaster is still losing energy. In simple tests. (A simple U shaped hill) the coaster will go back and forth losing very little energy. But the problems start to arise at greater speeds and sharper turns in direction. If you make a more V shaped track, but still a smooth trasnition from down to up, the coster will fly down and then go back up, but not as far as it should. Even with no drag or friction. From what I have tested, the energy is lost by tring to keep the wheel constraints at the proper location. In the "U" shaped test, the G-forces are low as the car is pushed back up and the wheel constraint can easily redirect the travel to follow the track. But in the "V" shaped test, the G-forces are greater then what the wheel constraint can handel (stragth and Tau = 100%) If you study the animation closely you can see that the wheel is pushed up compared to the coster cars. The wheel is push through the axle. Meaning the parent space (of the car) and the child space (of the wheel) are NOT in the same location. So energy is redirected to realign the wheel constraint so parent and child space are in the same location. Thus reducing the kenetic energy the coaster has and stopping short of its initial height.

Its kinda like putting 2 tons on a 1 ton trailer, your going to break the the axle, so to fix it you can add another axle. reducing the weight on each one. Thats the same thing you need to do with Reactor...Less wieght or more wheels to support it.

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