Tuesday, July 20, 2010

Cantilevered Coaster Catia Kinematics Trial #5

More work on my cantilevered coaster models. This one is different because the cantilevered beam is now fixed to the lower chasis. I have also begun playing with animating the viewpoints during the CATIA kinematics simulation. Next is to try and figure out how to do a POV video using the manikin's line of sight, and also adding the first curves to the coaster! Stay tuned...

Wednesday, July 14, 2010

Cantilevered Coaster Kinematics Test 4

Sky Rocket Design Flaw?

Sky Rocket at Kennywood is an amazing new coaster filled with wicked airtime in the inversions. However. there appears to be a design problem with the trains. Check out this picture.

It appears if you are a tall individual and sitting in row 4 the headrests from row 3 (last row of the first car)might be able to hit you in the knees. Apparently they've put a height restriction on row 3, 4, and 6. Has anyone been to the park recently and confirm this?

Monday, July 12, 2010

Animating the Cantilevered Coaster

I've recently been enjoying playing with the kinematics workbench in order to simulate my Cantilevered Roller Coaster Model. What little experience I had with the kinematics workbench was well over a year ago so it has been baby steps all the way.

There are two methods of simulation within the DMU (digital mock up) Kinematics workbench.
Method 1: Hand Animation. I like to call this first method hand animation because I believe that to be what it is like, animating a CG character for a movie. You set the positions of your commands where you want them to be an when you want them to be there. Sometimes can be a challenge to get smooth transitions.

Method 2. Laws. The other method of simulation in Catia kinematics is to create a trace law. You do this by essentially drawing or sketching a graph with the x axis being time and the y or vertical axis being distance from the starting point. This method is much quicker but sometimes can be more time consuming if you're using trial and error to figure out your desired movements.

Now, in regards to the Cantilevered Roller Coaster system, method 1 allows you to set the distances from the starting point of the upper and lower chasis independent of each other.This enables you to be able to animate exactly how you want to but this may not necessarily be how the system will react and real life.

Method 2 , there are two different options. You can use the same graph for each chasis or you can create two separate (but similar) graphs. Creating two graphs with this system is tricky because they can only vary by so much at certain sections of track. It's doable but make take a lot of iteration. Using one graph is simple but again I am not sure the real world scenario would act this way.