I can't make a smooth turn with the curve generator :(

I've been working on a NoLimits 2 recreation of the Riverview Bobs (see my thread in the Hard Hat area) and run into a snag with my turns.

Here is an explanation of how I make a turn:

Let's say my turn is 180 degrees, in 12 sections. All the banking is marked per bent on the blueprint, so we need 12 equal sections in the sim. Creating a 180 degree turn in the curve generator in one go gives me an unhelpful number of nodes which can't be easily divided by twelve. Solution? Create a segment which is 1/12 of the curvature of the turn, save that, and string several of them together.

Done. We now have a 180 degree turn made out of 12 equal pieces.

Next, find the blue nodes at the end of each section and raise them to the height required. Delete all other blue nodes in the section. What about the weird pearly-white nodes with a roll point on them? Delete - they serve to muck up the banking and prevent the curve from being smooth (I've tested this). You can't raise them either.

Done. Add roll angles on each of the 12 blue nodes; adjust banking accordingly.

Done. One photogenically smooth 180 degree curve, beautifully banked.

Ride in the sim. Pumpety pump, pump, pump.

Where am I going wrong? As far as I understand I've created a mathematically perfect curve, so by definition there shouldn't be any pumping anywhere.

I've tried using the feature on the curve generator which lets you set the exit height of the curve relative to the entry height. That didn't work either. A computer-generated curve should be smooth...shouldn't it?

[Coasterkidmwm]

Got a picture? What program are you using? If you're in the editor, is one of the nodes set to strict banking?

perhaps the pumps are caused from deleting all the extra nodes, have you tried using the depump feature? Instead of going at it from 12 individual turns try just one and then adjusting the pieces that you need?(you could use the "style separator" as markers for how long the track is, or if its a linear distance( from support to support intead of length of track) you could use a "dummy support beam that'll tell you how long each segment is.

The really cool thing about NL2 is that there are a couple different ways to go from point A to point B, you just have to find which way works best for the situation and not be afraid to use a couple of different methods to get there.

I think that we need a piece of information about the radius in feet of a 180 turn.

lol240 wrote:

I think that we need a piece of information about the radius in feet of a 180 turn.

In this case the radius is 30 feet.

I was able to get my 14 evenly spaced nodes by calculating the distance along the curve, dividing it by 14 and setting that answer as the minimum permissible spacing between nodes in the preferences window.

I'm now certain that the pumping is the fault of the curve generator. For clarity, I'm using the left curve generator in the library folder when you click "Add element". I created a brand new coaster so that the curve would not be affected by previous coaster track, and from the start vertex told the generator to add a 180 degree flat curve. It did. Then I selected all the nodes and told NL2 to depump the curve. The depumper changed the curve! This means that the curve is not smooth when the generator creates it, otherwise the depumper would've done nothing. At the very least it changed either the radius or the number of degrees of curvature around the curve.

I changed all the heights, saved the curve and attached it to the partially-built Bobs. It was still a little bit pumpy. Then I went back to the curve attached to nothing and changed all the banking and re-saved it and attached the banked version to the Bobs. This time the curve's pumping was worse. I even checked by creating a flat 180 curve on the Bobs, and the result was slightly pumpy - minimal, but still there. So the simplest explanation is that the left curve generator is flawed and is not producing smooth curves. Further, these curves are still not entirely smoothed after depumping.

At this point I'm not sure what to do. It's clearly not my fault. I can't complete the ride if I can't create smooth curves, because all twelve of the ride's curves are hill/curve combinations. Is it game over?

I bet that the original ride was not perfectly smooth at all. It probably had many small pumps since rides were hand built and probably hand calculated the gs back then and no simulation program was use to virtually make the coaster before it was built in real life.

Perhaps, but my curve is unrealistically pumpy - from the back seat you can see it jerking and twisting in ways it shouldn't, and to an extremely uncomfortable degree such that I'd worry about my neck.

Can you use the method that only makes the slightly pumpy track then?

cool5 wrote:

Can you use the method that only makes the slightly pumpy track then?

I tried that, but as soon as I started raising the nodes it all went wrong.

It may be helpful to have a photo of what I am trying to build, which is the lower of the two horseshoe curves in the following photograph:



As you can see, it is a perfectly circular 180 degree turn which rises as falls throughout the curve.

^ Whoa, the riders must have found that upward turn, really tight!