Hi everyone,

The Problem:

I am trying to generate a Roller Coaster which I want to use in Unity later on. The entire Coaster is "swept" along a single Curve. I need it to have a customizable rotation per point to tilt the track of the roller coaster, but Houdini doesnt seem to support that with its curve nodes.

How can I get a way to tilt the Track inside Houdini and Unity?

My tries to solve the Problem:

1: I created a curve in Houdini which is editable and duplicated it above to then point the normals of the first curve to the seconds curve points. While this works fine inside houdini i cannot edit the second curve inside unity.

2: I grabbed a curve addon from the unity asset store with customizable normal angles per point (the one from Sebastian Lague), but i cannot get the curve to be recognized as input for houdini. Neiter a HDA Input nor a object merge worked. I looked into the "input the curve as HDA" posts from some users, but that doesnt seem to work anymore.

3: I tried to make curve inside houdini and give the same points to a second curve via "copy parameters" of the first curves points, but the second curve doesnt recognise the points given via script.

I do really appreciate any help at all that could get me towards getting editable tilt on my roller coaster.
Best regards Moonwalk

One single bump because i have hope.

These might help..

https://youtu.be/o1vGKRcwFWw [youtu.be]

https://youtu.be/qJDMiDPGsMQ [youtu.be]

Thanks for the tutorials @gt3d2019. While I did not particularly used those, i did build something similar to them. However, I do not want to calculate some "fixed" rotations based on the points positions, i want to rotate them by hand so that i can go crazy with the banking whenever i feel like it. To show an example: https://youtu.be/saAQNRSYU9k?t=369 [youtu.be] Pretty much like this I would love to to the same in houdini. Or find a way to access that curve, which he builds in unity, in Houdini, especially with the normal rotation.

Still thanks for the Videos, those are great tutorials.

Hi,

I don't have experience with unity. But if you create a multiparm wrangle with control parameters for orientation based on u-Parameter. Is it possible to transfer it to unity?

I built a subnet that can do this, along with ramp control for falloffs, and can handle Roll Pitch and Yaw. I didn't convert it into a full-blown HDA because I rarely use it, and in its current iteration you'll need multiple instances of the subnet for different types of rotations, but again, that works fine for me because of its niche use.

I should also note that you can get selective roll rotations with the Edit node, it just can't do Pitch and Yaw, and probably not falloffs either. To get that to work, uncheck Recompute Point Normals, and set the Transform Space to Local Frame.

Wow, thanks for your two files, those are really helpful.

@Aizatulin Yours seems to work beautifuly but I still need to test this inside unity with an exposed parameter. This maybe does get a bit fiddly tho if i use it for a larger scale coaster xD

@eikonoklastes Your subnet is really prectical, but i think this will only work inside houdini an not in a unity session. However, can go a bit deeper inside the "edit roll rotation" topic you mentioned? I have not yet found a way to rotate a point of a curve.

Thanks to both of you two <3