View Full Version : Spline Instance Helix Problem Attn Node Gurus!

06-19-2014, 12:57 PM
I'm trying to get spline instance to make a helical structure. There is no control in the instance panel to distribute bank rotation over the length of the spline (That would be nice!), so I thought I could do it with nodes, but I'm getting some weird rotations. Every eight or so instances is not rotated. I know that I'm not very node savvy, but I think my setup should work. First I thought the instance IDs were broken, but a gradient in the surface editor works as expected. I've attached the scene, if anyone wants to take a look. I'm probably just doing something dumb. Please tell me if I am :)


06-20-2014, 07:29 AM
Your nodes work fine if instance type is set to Motion Path, I guess it's Spline Control that's causing the problem.

06-20-2014, 07:33 AM
Out of curiosity, was your spline made in Modeler first then converted in Layout?

If so, try making your spline from scratch in Layout directly. Should be pretty simple. Then apply your node settings.


06-20-2014, 08:50 AM
Thanks dee, I didn't think to try the nodes with Motion Path. It doesn't give me what I wanted ultimately, but it helps to track down the problem.
Ma3rk, thanks, that's a good idea too, but I get the same result if the spline is made in Layout. I'm going to post this as a bug and see what the devs have to say.

06-20-2014, 09:25 AM
When Spline Control is in Ribbon display mode, does it exhibit the same banking issues?

06-20-2014, 10:49 AM
Switching to Ribbon has no effect, and the ribbon is nice and straight (no kinks). The rotation is all in the node setup.

06-20-2014, 11:03 AM
Are the gaps entirely even, 8 rather than "8 or so"? --To me, that suggests some sort of modulo issue.


06-20-2014, 10:21 PM
The non rotated ones change with different numbers of instances, but they always seem to have some kind of pattern usually around eight or so

06-21-2014, 12:16 AM
OK, there's some types of rotations (Euler?) that don't smoothly increment up like degrees do, I vaguely and badly remember. You may need to do some translation between the two systems , or something.

Like, aren't rotations in the node editor in radians rather than degrees...... ???? :stumped:

06-22-2014, 05:11 PM
...Like, aren't rotations in the node editor in radians rather than degrees...... ???? :stumped:

Some are, some aren't. :)