IES instance light rotation

[Mikhalenko]

Hi,
I have a curve. And I instance IES lights on it. I want IES follow the curve but also look in the middle. I used N attribute for it from sweep, they follow, but they rotated in wrong way. I need that they lit the ground. But i found that changing rotation in IES light not affect instanced light, but similar work for other light types (rectangle). How I can rotate my ies light? Sorry for difficult description. Please check the scene attached

[chakarov]

Hello Mikhalenko, did you try to multiply @N by -1, this should orient normals opposite direction?

[tobbeo]

If you need 90 degree instead of 180 that multiplying @N by -1, you should be able to use dot. Otherwise just follow this quick tutorial:

https://youtu.be/7Irb2dqehL4

[Mikhalenko]

Hello Mikhalenko, did you try to multiply @N by -1, this should orient normals opposite direction?

Yes I did, but if I multiply by -1 I lose that IES follow the curve. First screen without @N * -1, second with. I attached also screen how I need that me IES light lit the road

[tobbeo]

A quaternion invert did the trick. See attached file.

[Mikhalenko]

A quaternion invert did the trick. See attached file.

and how I can control rotation over the axis using this?

[tobbeo]

and how I can control rotation over the axis using this?

That was just if you wanted them inverted. Fixing the normals was easy enough, see attached file. You need to merge back in your lights, but you can see the normals are fixed.

As with all things Houdini there are many ways to achieve the same result. The way you're scattering the lights is not how I work, I spent a few minutes trying to get your way to work but no luck. If I find some time later today I'll try to look at it again. In the meantime I hope the Chaos guys help you reach the finish line.

[Mikhalenko]

Hi, Thanks, It's work with one axis, but I need rotation around each axis. I think the problem in IES light that instanced, because rotation parent IES not tranfer to instanced

[Dubbie99]

Can you just use the orient attribute to set the orientation of your lights?
Then you can set it exactly how you want? Or am I missing the question somehow?

[Mikhalenko]

Orient attribute nor affect on orientation of light< or I do something wrong

[Dubbie99]

I just tried applying a random orient attribute to some points and instancing the lights on.
Seemed to work just fine?